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Paints

In: Paints

Turpentine Oil vs. Mineral Spirit

When using oil colors for painting, it is common to thin the paint for more precise application, glazing, or improved blending. While linseed oil (or another drying oil) can be used for this purpose, the addition of oils and gums in painting can extend the drying time, which may be inconvenient for many artists. Personally, I do not mind waiting, but not everyone are like that.

Typically, artists use turpentine oil or solvent as thinners for their paints. Both substances have a strong odor and can be toxic if used without adequate ventilation. Even if the odor is masked, the toxins remain present due to their intended purpose of quick evaporation to expedite the drying time of the painting. However, for the purpose of this discussion, I will focus on the physical effects on oil painting rather than the toxicity aspect (assuming you are already aware of and accept the risks). 

What is turpentine oil?

Turpentine, known by various names such as spirit of turpentine, oil of turpentine, or wood turpentine, is a liquid derived through the distillation of resin extracted from live trees, primarily pines. Technically, it’s a natural product.

When reviewing product labels, it’s important not to confuse turpentine oil with turpentine gum. Turpentine oil is a liquid with a strong (toxic) odor and is used as a thinner, whereas turpentine gum is a solid pine sap. The gum can be transformed into a honey-like consistency by heating and mixing it with oil (such as linseed oil) or by dissolving it in solvents.

In oil painting, turpentine oil serves as a thinner without acting as a solvent that disrupts the bond between the oil and pigment. Turpentine oil, classified as a volatile oil, evaporates quickly, hastening the drying process and facilitating paint blending without compromising the bond. However, overuse of this thinner can weaken the underpainting layer and elevate the risk of peeling, as it diminishes the adhesion between the paint and canvas. It is advisable not to exceed a 50% ratio of turpentine oil to your chosen painting oil (such as linseed or walnut oil) for optimal results.

Pure turpentine oil, without added solvents, should be stored in a dark place (such as a light-protected container) and used within one year from the date of manufacture. Such restrictions and also costs of production led manufacturers to substitute turpentine oil with solvents.

What is solvent?

Mineral spirits are derived from petroleum. They have gained popularity among artists due to their lower cost (compared to turpentine oil), reduced odour, and easier storage requirements. With the introduction of odourless solvents, manufacturers even eliminated the “skull and bones” label to indicate non-toxicity. However, subsequent research revealed that even in the absence of odor, the product remains highly toxic. Anyway, I promised, not to dig here.

Apart from turpentine oil, mineral spirits, or solvents, break the bond between the oil and pigment. This was the original purpose of these products – to effectively clean grease, oil, and other substances from surfaces. 

When used with care, solvents appear to function similarly to thinners by accelerating drying time and thinning the paint. However, if solvents are applied in the same manner as turpentine oil, the paint application may become uneven, the painting layer can become excessively fragile, leading to potential cracking, and the adhesion between the paint and the canvas may decrease. Additionally, solvents can impact previously applied layers by removing and slightly damaging them.

So, turpentine oil and solvents are not the same or even similar products. Turpentine oil is a thinner, while mineral spirit is a cleanser.

In: Paints

Have you heard about Neodymium or Erbium oxides?

These two rare colours have been newly incorporated into ENL watercolour paints (half-pans). Neodymium and Erbium oxides, both classified as rare earth oxides, caught my interest to experiment with them in watercolours. While these oxides are commonly utilized for ceramic glazing and industrial applications, the use of these elements in paints is a novel discovery for me.

Neodymium Oxide

The name “Neodymium” is derived from the Greek words “neos didymos”, meaning new twin. It refers to the chemical compound consisting of neodymium and oxygen, represented by the formula Nd2O3. In terms of appearance, it presents as a pale lavender-blue powder. Neodymium Oxide exhibits excellent lightfastness, is insoluble in water, and imparts a delicate pastel lavender-blue hue. This chemical is notably stable, making it a secure choice for watercolour paints and environmentally non-toxic.

Erbium Oxide

Carl Gustaf Mosander first isolated impure erbium(III) oxide in 1843, with the pure form being obtained in 1905. Erbium(III) oxide is a pinkish solid that is insoluble in water. When used in watercolours, it imparts strawberry milkshake hues with a granulating touch. Apart from many modern pigments, Erbium Oxide is non-staining. 

Both of these colours will prove advantageous for landscape artists, particularly when used for depicting the sky. In creating the paints, I used pure oxides with the binder, ensuring that no fillers were incorporated. Despite their “milky” appearance, these colours remain transparent and avoid the chalky quality often seen in mixes containing titanium or zinc white.

In: Manufacturing

Fun Facts About Art Supplies

When 1/2+1/2 is greater than 1

A “half pan” is not precisely half in terms of volume. The difference between a half pan and a full pan can be as little as 0.5 ml in volume. When a half pan is well loaded, it typically holds around 1.5 ml of paint, while it can accommodate up to 2 ml when filled slightly above the walls. On the other hand, a full pan generally has a volume of 2.5 to 3 ml. Therefore, even when fully loaded, a full pan contains less paint compared to two half pans.

When the worst is the best

Over the course of many centuries, the quality of hog bristle, a material commonly used by oil painters, has declined in Europe. This decline can be attributed to the improved living conditions provided to pigs in Europe, which resulted in a decrease in the quality of their bristles for painting purposes. Interestingly, the quality of hog hair for brushes is now found to be superior in regions like China, even for brushes made in Europe. This is because the hair from pigs raised in more challenging environments tends to be of higher quality for painting purposes.

Re-assembled Linseed oil

The quality of linseed oil used for painting is influenced by the conditions in which the crop is grown. Generally, colder climates tend to produce higher-quality oil, making northern crops more suitable for artistic use. In order to reduce dependence on natural conditions, many manufacturers refine linseed oil through multiple stages. This refining process involves the removal of certain amino acids and proteins, followed by the addition of only those that provide benefits for artists. As a result, this refined oil resists yellowing over time and also dries at a faster rate. However, we don’t know how such processes affect painting in a long-term perspective.

Acrylic Focus Pocus

Acrylic paints have the ability to undergo self-polymerization, which allows them to form a dry film even when stored in a closed container. To prevent this unintended drying process, manufacturers often incorporate ammonia or other chemicals into the paint formulation. These additives help to inhibit the self-polymerization and maintain the paint’s usability over an extended period of time.

In: Paints

Acrylic vs. Oil: Conservation Properties

Many artists dream about having their work exhibited in museums that would preserve art for generations. Even if your painting is not going to get there the question about the archival properties of your work is still important. Some art can show signs of deterioration, such as:

1. Fading or discoloration. Over time, exposure to light and environmental factors can cause colours to fade or change. This is particularly noticeable in artworks created with pigments with poor lightfastness.

2. Cracking or flaking. Paintings, especially those done on canvas, may develop cracks or flakes due to aging, changes in humidity, or improper handling/storage. This can result in the loss of paint layers or sections of the artwork.

3. Yellowing or darkening of varnish. Varnish applied to protect and enhance the appearance of a painting can yellow or darken over time, altering the original colours and clarity of the artwork.

4. Mold or mildew growth.

5. Loss of adhesion. In some cases, the layers of paint or other materials may detach or lose adhesion to the support, leading to flaking or detachment of sections of the artwork.

Let’s take a look at these aspects of oil and acrylic paintings.

Fading or discolouration

In oil, it can come from two aspects: wrong pigment use or wrong conditions of paint application. If we compare oil to acrylic, pigment use will be about the same. As both refer to opaque mediums, pigments are supposed to have similar lightfastness at use. However, oil drying processes are much more complex and longer than for acrylics, so fading can occur if drying is happening at lower temperatures and unstable or high humidity. 

For acrylics, during the water evaporation process, discolouration may be noticeable much faster. It’s not an actual colour loss, but rather the effect of wet colour vs. dry colour (similar to a wet and dry rock). Also, generally speaking, professional oil paints have a higher pigment load in the tube than acrylics and fewer fillers and thickeners that help keep colour almost unchanged from application to the end of the visible drying process (provided that storage conditions are met). Excessive fillers may make paints “milky” and less vibrant after full drying, especially in acrylics.

Cracking or flaking

Oil paints, generally speaking, potentially develop more cracking than acrylics. Especially, if an artist didn’t follow the “fat over lean” rule. Fat over lean refers to the principle in oil painting of applying paint with a higher oil-to-pigment ratio (‘fat’) over paint with a lower oil-to-pigment ratio (‘lean’) to ensure that the film is flexible and durable. 

The Canadian Conservation Institute (CCI) points out that oil paintings are particularly vulnerable to low relative humidity (RH) conditions, which are very common indoors during Canadian winters. 

In low RH conditions, the size, ground and paint layers become more brittle and higher stress within the layers can develop. Below 35% RH, they are more likely to develop cracks, which in turn can lead to lifting paint and paint loss. Also, RH fluctuation of more than 10% can contribute to cracking, especially for impasto paintings. In other words, storage conditions are very important to prolong an oil painting’s life.

What about acrylic paint, there is currently extensive research being undertaken to increase our understanding of the composition and properties of modern paints. Even though acrylic paints form a more flexible film than oil paints and seem less prone to cracking, we don’t have statistical data enough to determine if similar defects develop with natural aging. 

What we know is that acrylic paint becomes more vulnerable to cracking at moderately low temperatures. It increases dramatically in stiffness at temperatures of +5 …10 °C, which is not too low considering Canadian winters. The potential for cracking at these temperatures makes handling and transporting paintings questionable in Canadian winter conditions. 

Yellowing or darkening of varnish

Usually, this is attributed to oil paintings, especially quite old ones. To protect the painting surface, we use damar varnish that tends to yellow and darken with time as it absorbs dust and some humidity from the environment. The good news is that it’s fixable. There are tons of successful restoration works performed over time when the old varnish was cleaned or/and re-applied. Painting layers themselves were not affected.

Even though acrylic varnish doesn’t yellow with time, it doesn’t provide proper protection for the artwork. According to CCI, acrylic paints tend to attract and absorb dirt at ambient or high temperatures making it impossible to clean the surface of acrylic painting without affecting and damaging the paying layer. Because of these, the CCI suggests protecting acrylic paintings with glass. 

Mold or mildew growth

High humidity or improper storage conditions can lead to the growth of mould or mildew on artworks, particularly on wood or canvas materials. Both acrylic and oil paintings may be affected by this equally.

Loss of adhesion

Here, we should go deep inside the polymerization process. In chemistry, monomers are molecules that can react with each other to form a larger polymer chain or three-dimensional network. This process is called polymerization and it goes differently for acrylic and oils.

Oil creates a durable bond with most of the surfaces, including metals, forming a flexible film. If the surface is porous, the bond will be even stronger. Acrylic polymerization takes place within itself and the only thing that holds the paint is its penetration to a porous surface normally provided by acrylic primer. That explains why acrylic paints are so easy to peel off from your plastic, glass, or even wooden palette. And, of course, the same thing may happen to your painting.

In: Manufacturing

Acrylic vs. Oil: What Is Toxicity And How To Manage It

If you read an article about the VOC content of paints, you may have a valid question: why all these paints are not labelled as toxic? I’ll tell you more, all they will have a label “non-toxic”. The reason is that the term “toxic” is limited by ingredients that cause “adverse chronic health effects” and “acute and/or chronic health hazard”.  In other words, if acute exposure to a certain paint doesn’t damage your body enough to the stage when it’s unreversible, or medical assistance is needed, the paint is officially non-toxic, and it’s your responsibility to provide proper ventilation and use protective equipment (glasses, gloves etc.) 

However, paints that contain cobalt, cadmium, lead, nickel, and many other heavy metals and major harsh toxins have to be marked as toxic. The USA is much stricter in this matter and the list of ingredients that would have warning signs is much longer. You can find it here: https://www.p65warnings.ca.gov/

All these are reasons why MSDS for the same kind of paints usually split for paints that don’t have toxic pigments and paints contain them. Lists of colours described by “non-toxic” and “toxic” documents usually are included by manufacturers. 

For some reason, even the industrial paint industry has much clearer labelling and standards than artist’s paints. Most of them show a list of ingredients and disclose VOC levels as well as precautionary measures. Anyways, as each of us has only one body and we’re going to carry it until the end of the day, that’s our responsibility to take proper care of it. Let’s take a look at how to provide safety in the workplace.

Oil paints and toxicity

As we mentioned in the previous articles, most of the toxicity of oil paints comes from solvents. Turpentine and white spirits as well as tons of odourless variations of those drag toxicity to the oil painting process. Yes, solvents ARE hazardous, cause eye and skin irritation, and may cause drowsiness or dizziness. Solvents may be fatal if swallowed and enter airways. Simply DO NOT USE SOLVENTS! Solvents are OPTIONAL for oil painting.

Another source of toxicity comes from certain pigments. However, such pigments can be present in any kind of paint (oil, acrylic, watercolours, gouache, tempera etc.) and are not exclusively linked to oil painting.

Technically, if you avoid them your painting process is non-toxic. Some manufacturers may add solvents inside the tubes, but now it’s getting less and less common. However, I recommend checking MSDS just in case and choosing your brands wisely.

Oil paints dry slowly and release VOC slowly as paints dry, so give your artwork 6 months or more before having it in the bedroom. Even though the VOC level is quite low there, it’s better to be on the safer side.

Because oil is quite a flammable material it’s recommended to take extra caution and avoid painting close to fireplaces, working heaters and other places that have potential fire hazards. The flashpoint of linseed oil is about 93 Celsius. 

We will talk about the storage and cleaning up process in further topics.

Acrylic paints and toxicity

The same as for oil painting, watch for pigments used. If you are sure that cobalt or cadmium may harm you, then just ignore this part.

When people say acrylic is “water-based”, they associate this statement with safety. Yes, acrylics do contain water that carries all ingredients and pigments, but it’s not a base, it’s one of the ingredients. As the acrylic polymer dispersant contains styrene, an alkyl methacrylate or a mixture of styrene and an alkyl methacrylate, you should take measures that keep your workplace safe. 

Methyl methacrylate can cause skin, eye and respiratory irritation. As we discussed before, proper ventilation is required, unless you paint outdoors. Health authorities recommend typically 10 air changes per hour. If special equipment is used for ventilation, make sure it’s fire-proof as the methyl methacrylate vapours are highly flammable. 

Styrene is a chemical used to make latex, synthetic rubber, and polystyrene resins. When you breathe air containing styrene, most of the styrene will rapidly enter your body through your lungs and will be broken down into other chemicals that leave your body in the urine within a few days. The International Agency for Research on Cancer (IARC) has determined that styrene is a possible carcinogen.

However,  the most dangerous guy in acrylic paints is ammonia. According to technical information, ammonia is a flammable gas that may form explosive mixtures with air. It may displace oxygen and cause rapid suffocation. It’s harmful if inhaled and can cause severe skin burns and eye damage. 

For acrylic painters, health authorities recommend wearing protective gloves and clothing and using proper eye protection. Keep your paints away from heat, hot surfaces, sparks, open flames and other ignition sources. Avoid smoking, drinking and eating in the room. Use paints only outdoors or in a well-ventilated area.  

 

In: Manufacturing

Acrylic vs. Oil: VOC

In this series of articles, I’d like to look at these two mediums from a professional and responsible artist’s point of view, thinking about the artwork itself and the impacts that working with these mediums includes. There is no straightforward answer to what’s better and I don’t think such a question can be valid; this article is aimed to make an informed choice for this or that art project. I’ll try to be as straight to the point as possible.

What is VOC? 

Volatile organic compounds (VOC) means any compound of carbon (excluding carbon monoxide, carbon dioxide, carbonic acid, metallic carbides or carbonates and ammonium carbonate) that participates in air. Some VOCs have a distinct smell, while others may remain unnoticeable. Exposure to VOCs in indoor air may affect your health, depending on which VOCs are present, the level of VOCs present, and how long you are exposed. 

Some examples of VOC include formaldehyde, benzene, ethylene glycol, d-Limonene, toluene, acetone, ethanol, 2-propanol (isopropyl alcohol), methylene chloride, tetrachloroethylene and many others.

The World Health Organization (WHO) recommends a guideline value of 0.3 mg/m³ for total VOCs in indoor air.

Both oil and acrylic paints (we’re talking about artist paints, not industrial) emit VOC, but in different quantities and in different ways. You can find the information about VOC in the Material Safety Data Sheets (MSDSs) that most manufacturers provide. 

MSDS for the same product vary depending on country regulations and usually split based on pigment groups:

  • containing cadmium and cobalt
  • containing zinc oxide
  • and all the rest
  • These extracts refer to “all the rest” based on regulations in the same country and state (county).

Before we refer to the facts, let me ask you a question, Which paint would you choose, the first or the second?

“SECTION 7: Handling and storage  

7.1. Precautions for safe handling Precautions for safe handling: Ensure good ventilation of the workstation. Wear personal protective equipment. 

Hygiene measures: Do not eat, drink or smoke when using this product. Always wash your hands after handling the product.  

7.2. Conditions for safe storage, including any incompatibilities Storage conditions: Store in a well-ventilated place. Keep cool.”

“SECTION 7: HANDLING AND STORAGE 

Precautions for Safe Handling: Read and observe all precautions on the product label. Wash hands after use. Immerse contaminated rags in water. 

Cautions for Safe Storage: Store away from high temperatures, sparks, or open flame”

I’m not sure what would you prefer, but I’m voting for the second. The first one describes acrylic paints, and the second one refers to oil paints (I’m not disclosing brands here). 

Even very high VOC in paints doesn’t qualify to be labelled “toxic” as VOC compounds do not stay in your body for long being broken down and released with urine. However, prolonged exposure to VOC vapors can cause a variety of health effects, such as:

  • eye, nose, and throat irritation;
  • headaches, migraines and loss of coordination;
  • nausea and damage to the liver, kidneys, or central nervous system.

VOC in Oil Paints

In general, the VOC of artist oil paints (not industrial ones that you buy in construction stores) is less than 2 g/l. Meaning, for example, if you’re painting in lean technique and use 10 ml of paint, which is about a tablespoon size, your paint will emit about 20 mg of VOC and to maintain healthy standards 66.7 m3 of room space is needed. If your ceiling height is 2.5 m, a painting room should be 26.6 m2 or larger to maintain healthy balance.

If you’re painting in impasto technique, you’ll need a room about 10x larger. 

However, oil paint releases VOC slowly, while paints dry, meaning that the concentration of VOC will be lower than those estimates.

To keep oil painting safe, just don’t use or add turpentine oil or solvents. They have almost 100% VOC, reaching up to 1200g/l. Use linseed or other drying oil, solvent-free mediums, cleaners and varnishes. Keep your painting on the safe side.

Cheap oil paints may have solvent inside and emit more VOC.

VOC in Acrylic Paints

Generally, the VOC of artist’s acrylic paints is about 50g/l. For a lean technique, let’s use the same 10ml of paint. They will contain 500 mg of VOC and with the WHO’s norm of VOC level 0.3 mg/m3 we’ll need 1666.7 m3 of space, which is about 667 m2. If you paint in the impasto technique, multiply this number by 10.

The good news is that all VOC is emitted during drying time, which is quite fast and after the painting is cured, the VOC level is 0. In other words, in 1-2 days air quality with proper ventilation and filtration goes back to normal.

To compare, acrylic paints that contain mica powder (in other words, all metallic paints) have a VOC of about 300 g/l, and acrylic varnishes have 100 g/l. I saw artist’s acrylic products with VOC 500 and higher. Some acrylic gels and pastes may have very low VOC as no pigment or excessive water was added.

Acrylic dispersion/emulsion itself has a very low VOC. Making acrylic paints by yourself and using them right away is another solution to avoid intoxication. What is inside acrylic paints and why, you can read in the previous article.

In: Manufacturing

Acrylic vs. Oil: What Is Inside The Paints

In this series of articles, I’d like to look at these two mediums from a professional and responsible artist’s point of view, thinking about the artwork itself and the impacts that working with these mediums includes. There is no straightforward answer to what’s better and I don’t think such a question can be valid; this article is aimed to make an informed choice for this or that art project. I’ll try to be as straight to the point as possible.

Oil Paints

Historically, oil paints are made from pigment and oil. However, fresh-made paints, especially if they contain mineral pigments, will start separating within a very visible time frame (some paints show separation even after a week from the manufacturing date). Copper Oxide pigments separate in 5-7 days, and earthy pigments, depending on their particle size, within 1-3 months. Organic pigments, due to their lightweight nature, may not show any significant separation even after a year of manufacturing. Pigment use is a separate topic, so I’m not going to pull it here.

As it can take 5 or even more years between manufacturing time and actual purchase and consumption time, manufacturers need to make sure that their paints are still presentable. So, to stabilize paints (depending on pigments) they use wax pastes as well as barium sulfate. To increase the quality of the painting and the elasticity of the film, some resins can be added. Usually, it’s turpentine gum (don’t mix it up with turpentine oil), dammar, mastic etc. To shorten drying time a small amount of turpentine oil may be added.

Some paints, depending on pigments and grade (studio, artist, pro) may have fillers that usually have a mineral nature: kaolin, marble dust, calcite, barite, talc, etc.

Professional paints have pigment, oil, wax, resins and a minimal amount of fillers.

Acrylic paints

Here, everything is much more complicated. Long story short, here is a list of ingredients:

  1. Pigment. The same as for oil. The different pigments used for acrylic and oil will be covered in a separate article. 
  2. Binder. It’s either acrylic dispersion or emulsion or both. They contain styrene and/or an alkyl methacrylate. The alkyl methacrylates used are methyl methacrylate, isodecyl methacrylate or stearyl methacrylate. Many terms, but all these can be simplified as monomers that form polymers after the carrier (water) evaporates.
  3. pH adjuster and dispersant. When we paint in acrylic, we expect that paint will be easily spread, and mixed with other colours. That’s why ammonia is an essential acrylic paint component. Pigments, as we know, are solid particles and tend to settle down on the bottom of the pain container with time. Ammonia helps to disperse the pigments evenly throughout the paint, thereby providing nice consistency and colour uniformity.
  4. Surfactant. These chemicals prevent paints from early cracking and provide an even drying process. Here we have ammonia again, glycerine, and propylene glycol.
  5. Fungicide. As acrylic has water inside and some organic and inorganic ingredients, paints need to have preservatives that stop mould growth. Here, it can be ammonia, formaldehyde, or petroleum by-products.
  6. Paints, that contain mica powder as well as very thick paints may contain solvent to prevent separation and prevent paints from drying in tubes.

Ingredients used in paints deal with safety and health issues. 

In: Paints

When Mono-Pigment Colours Are Not Mono-Pigment

This also happens. And here we’re talking about fillers and extenders. Generally speaking, all organic pigments will have a certain amount of other components used as a base. They just need to have some particles “to stick to” and create a body of paint. This doesn’t count as a filler as a mineral base is NEEDED for such paints to exist.

However, there is no certain regulation that would place a border between the necessary and extensive use of fillers. That’s why many paints, either organic or inorganic, synthetic or natural,  potentially may contain more than just listed pigments. Common fillers include PW5 (Lithopone), PW18 (chalk), PW19 (Kaoline), PW21 (Barium Sulfate) and others.

In: Paints

Monopigment vs. Multipigment Paints

There are many debates regarding what’re better mono-pigment or multi-pigment paints. As all artists are different and hence have different preferences it’s hard to say what is better. From the chemical point of view, these questions can be answered if we have full information regarding each specific paint colour’s ingredients. As this is impossible, let me share some ideas and approaches to Mono-pigment vs. Multi-pigment paints.

Benefits of mono-pigment paints

Generally speaking, mono-pigment paints seem to have a better reputation than mixed pigments. The main benefits include:

  • More predictable results in mixing
  • No pigment separation
  • Even consistency
  • Higher pigment load
  • More stable colours

However, the choice is not that straightforward. Things were easier to understand a century ago, when pigments were mostly mineral or natural, with well-known properties and composition. Now, heavy-metal pigments, such as lead, cobalt, cadmium, nickel and others are getting substituted with manufactured pigments. More and more synthetic pigments come to the market and their properties are still being tested.

Mixing Organic and Inorganic Pigments

There is no perfect solution for mixing colours, and every mixture of pigments has its own pros and cons. When it’s about mineral and inorganic pigments, I’d say mono-pigment colours are better as they are more predictable. Ideally, mineral pigments have no fillers or extenders, so having pure colours is much more beneficial. All metal oxide pigments are like that. 

For example, iron oxide colours depending on their place of extraction may have different impurities that bring interesting hues and shades. Pre-mixed colours reduce the range of possible experiments.

However, when it’s about synthetic organic pigments, things get different. Since all organic pigments need a base, different tubes may have different combinations of bases and fillers. It can be kaoline, chalk, marble dust, barium sulphate, aluminum sulphate, silica, mica, titanium white etc. If we want to make orange from yellow and red, we may not be able to, because our paints may contain fillers in various proportions. As a result, mixing colours on a palette is less predictable and brings more struggle. 

Also, we should take into consideration that the mixing process itself for paint-making and for painting is different. Manufacturers mix pigments first and then add the base and fillers. Artists mix together the products. 

Organic pigments are super-fine. So, mixing them at the manufacturing stage allows them to get homogenous mixtures and even colouration. When artist mix ready paints, at the micro level, mixed orange, for example, is still yellow and red as organic pigments don’t interact with each other unless literally rubbed into a base.

For mineral paints, having mono-pigment colours is much better. For orange, it’s better to use PO colours than to mix red and yellow. The reason is the same, at the micro-level red+yellow for mineral pigments is still red and yellow. 

What To Avoid

And for any colours, whether organic or inorganic, I’d suggest avoiding paints that contain white in mixtures (unless we’re looking for hues, such as flesh colours, for example). If yellow has white and red has white, mixing them together will give peach colour or muted orange, but never bright orange. 

In: Paints

When Multi-Pigment Colours Are Not Multi-Pigment

If even 50 years ago only mineral pigments were considered to be professional, with modern chemical industry development we have more and more new and reliable pigments. Even though we still use natural pigments, especially iron oxides, companies learnt how to manufacture those pigments.   

History knows iron oxides being used for art since cave drawings. Even now, the greatest variety of colours belongs to PY43, or Iron Oxide Yellow. Extracted from different areas around the world, this pigment gives many different colours with different opacity and granulation. 

However, for commercial brands stability in colour is one of the key goals. When you dine in a restaurant you expect the same dish to be cooked the same way every visit. The same is happening in art supplies industries: the same colour has to be the same from batch to batch.

To achieve more stable and predictable results, manufacturers use PY42, a synthetic (man-made) version of Iron Oxide Yellow. The same as natural oxide yellow, this pigment offers a wide variety of colours of different grades of transparency. Differently treated, it will give almost any shade of yellow, orange, red and brown.

Even though we mark PY42 and PY43 as different pigments, technically, they are the same. So, when you see PY42-PY43 label on a tube of paint, this paint is considered to be mono-pigment. Some other pairs of pigments that can be used interchangeably include PR101 and PR102, PR122 and PR202, and all pigments with extensions (PB15, PB15:1, PB15:2, PB15:3 etc, PR48, PR48:1, PR48:2 and so on).

In: Paints

Shades of Black

Black is a very contradictory colour: some artists even prefer not to have it in their palettes and mix it when needed. I personally think that black is a very important colour as it creates very beautiful mixes, as well as works better as mono pigment black rather a mixed one.

In ENL Watercolours in pans, I made 4 blacks for now.

  • Brown Black is semi-transparent granulating colour made of two mineral pigments: PBr 8 and Iron Black PBk11.
  • Vine black is called sometimes Black Ochre (PBk8) is made by burning vegetable matter in a low oxygen environment. Vine or willow charcoals are made in the same way and the name comes from the grape vines used in one of the manufacturing methods. This colour is transparent and gives almost no granulation.
  • Mars Black, or PBk11, is the first black I’ve ever made in watercolours. This mineral colour provides transparent granulating coat, but the particles may seem gritty due to the nature of the pigment.
  • Lamp Black is a new one here and I had big doubts to include it or not in the line. The problem is in the method of production, when petroleum or natural gas get burnt and then the soot is collected. Even though the pigment itself is safe to use, the manufacturing process contributes a lot into carbon pollution. The colour is opaque with a very strong tinting properties which makes it difficult to mix with other colours (whatever you mix, you get just another black). However, for crating backgrounds or very dark spots Lamp Black is essential.
In: Paints

Iron Oxide Red PR 101-102

After Iron Oxide Yellow (PY42-43) by the number of variations in colours, another iron oxide goes – Iron Oxide Red (PR101-102). Even though PR101 and PR102 have different indexes, both describe the same iron oxide red with the only difference: PR102 is natural and PR101 is a synthetic, or man-made one. 

PR102 is mostly manufactured by the calcination of hydrates of iron, and depending on the time and amount of calcination the colour can vary from yellow-orange and brown to violet-red. Although most PR101-102 colours are opaque, iron oxide red can show different grades of transparency, from transparent to very opaque one with very strong tinting properties.

The most common names include English Red, which is a kind of bright brick colour. The name of the colour comes from the military uniform that was officially adopted in England in 1645. Beyond the symbolic meaning, the choice of red colour had also financial reasons – red colour was the cheapest one available back then as it technically comes from mineral clays. Officer’s coats were bright red, and soldier’s coats were of rather brick colour, the same as traditional English red.

A lot of iron red colours have “Mars” as a prefix because in alchemy, the “Red Planet” Mars is standing for iron as an element. Usually, Mars colours describe transparent versions of PR101-102.

Another common name for colours from PR101-102 family is Indian red. The first recorded use of Indian red as a colour term goes back to 1792 and has absolutely nothing to do with the skin colour of Native Americans. The name derives from the red laterite soil found in India, which is composed of naturally occurring iron oxides (PR102) and has red-brown colour with a violet undertone.

Very beautiful caput mortuum colour doesn’t sound too optimistic. It comes from Latin caput mortuum meaning “death’s head”. Alchemists used this term for the ultimate remains of an alchemical process signifying something not changeable and as a result worthless to them. Caput mortuum represents a violet semi-transparent version of Iron Oxide Red. 

According to another version, caput mortuum colour refers to olden times when the colour was manufactured using ground-up pieces of mummies. Europeans began manufacturing caput mortuum back in the early 16th century. At the time, there was a thriving trade in mummified remains between Egypt and Europe. Paint manufacturers kept producing organic caput mortuum until the beginning of the 20th century when the usage of the colour dropped off due to ethical reasons. Then this colour was replaced by its synthetic cousin – Iron Oxide Red. 

In ENL Watercolours you can find many colours made with PR101-102 as mono pigment use, from bright red-orange (Ercolano red) to transparent violet (Cocoa Rosso Natural). And, of course, no mummies or zombies were used to make these colours.

In: Paints

Acrylic Paints for Decorative Arts

For craft purposes, such as decorating wooden boxes or painting on leather or fabric, acrylic paints work best. They mix well, can be applied easily, dry fast, form permanent film, and the cleaning is quite simple. Although all acrylic paints have pigments (or dyes) as a colour agent and acrylic dispersion (or emulsion) as a binder, they are not the same for different purposes.

Acrylic paints for fabric contain a special plasticizer, so after use and stretch your painting will stay. Paints are usually thinner and go inside the treads, that’s why absorbing cotton is one of the best materials to use for textile painting. 

Paints for silk are even thinner and look more like ink rather than regular acrylic paints as silk is very fine and colours should penetrate inside and between the treads so no film is left on the surface.

For leather, acrylic paints for fabric work very well, but they may not have enough adhesion. Even though we remove all grease from the leather top surface, perfect cleaning is not really possible, and paints may peel off the surface. So, special paints are recommended.

Hot techniques in glass and ceramics provide the best effect as they kind of fuse to the surface and form a semi-permanent connection between the materials. For cold techniques, acrylic paints can be applied. And here regular acrylic paints do not work well. Glass is very sleek and regular binder doesn’t stick to its surface very well. That’s why special acrylic paints for glass and ceramics have a special bonding agent to provide extra adhesion. Glass paints can be transparent or opaque, creating beautiful stained glass effects.

Another special kind of paint is metallic-looking paint. Don’t fool yourself, gold paints have no gold, just mica powder to achieve a sparkling look. Mica particles just reflect the light and, being coloured, they imitate different kinds of metal: gold, silver, copper, bronze or even some exotic colours. However, they will look metallic just in certain light. Also, paints with mica powder usually contain solvents and stabilizing agents for smoother application and to prevent the separation of mica particles. For a true gilding experience, use our gilding kit. It doesn’t have gold or silver either but creates a solid metallic look regardless of the games of light.

In: Paints

Watercolours: Pans vs. Tubes

There is no straight answer to what’s better – tubes or pans. Here, I’ll try to explain how things work from the artist’s and chemistry perspectives.

From artist’s side, we’re talking about techniques and other materials used. For washes and work on cold press tubes work better as they provide even coverage and perfect blending. It’s easier to mix desired colours, create a paint solution in water and work in wet techniques when watercolours are soft and creamy. However, there are some issues that watercolorists may struggle with. 

First of all, that’s adding values. Obviously, watercolour is a transparent medium, meaning that light is coming from the paper itself. If for oil or acrylic we can create values and shades by mixing colours; sometimes, even colour matching, in watercolours, the value is mostly controlled by the amount of water used. If paints already have a solution form, adding values may be challenging. Even with multilayering techniques, every next application, if it’s watery, can wash out the previous coating, meaning no value is added, just colours got changed. 

Adding values is much more controllable with watercolours in pans. So, watercolours in tubes are perfect for laying out, washing, and underpainting, for sure. 

Watercolours in tubes are also very handy for illustrators working in paint and ink techniques. The colours and transitions look amazingly alive and the ink just adds a finished and styled look to the illustrations. Also, ink can add some value to shadowed areas and bring a complete appearance. 

For a deeper 3D look, watercolours in pans make more sense. You can control values, colours and amount of water used. However, wet-on-wet may be quite challenging here.

Also, there is a practice to transfer tubes into pans and “save” on watercolours in pans and watercolours in tubes may be cheaper per ml. However, this practice doesn’t bring watercolours into a pan stage. Let me explain why.

Pigments have different masses, particle sizes, and densities, meaning they may be heavier or lighter than a binder, absorb more or less of it and provide granulation or not. For example, mineral pigments (such as ochres, siennas, oxide chromium, cobalt, and cadmium) are quite heavy and being suspended in liquid will eventually settle down and separate from the binder. To prevent it, manufacturers use different agents as well as super-pigments that can be dissolved in water and keep the colour. (In ENL watercolours I’m using super-pigments too to enhance the colours). 

Another goal of watercolours in tubes is to keep them soft and liquid, so they can be easily squeezed out. That means more glycerin as well as other agents can be added more extensively to the colours that tend to solidify fast. Also, to improve the first impression experience a lot of watercolours in tubes contain unnecessary fillers. So, you grab the colour and it looks intense, and you’re happy. But when trying to spread it with water, it loses the chroma very fast, making creating transparent layers impossible. 

Preserving watercolours in tubes by transferring them into pans doesn’t solve any of those issues.

Watercolours in pans require more work and time from manufacturers. During the drying process, water evaporates and paints get solid. It may take 3, 5, or even 10 or more cycles before water the pan is ready to go. Each time, manufacturers have to add paint to pans to make sure it’s full. So, by texture watercolours in pans and in tubes are not the same.

Another aspect to consider is the pigments used. As we discussed before, pigments can be natural, synthetic, organic, inorganic, or mineral. Particles of synthetic organic pigment, such as phthalo-, azo -, naphthol- etc., are finer in size and require more binder to create a homogenous mixture. This also means that keeping these colours transparent with minimum fillers added for pan production is a challenge: paints either don’t solidify well, or more fillers are required. It makes more sense to have this colours in tubes, rather than pans.

Why watercolours fade
In: Paints

Why watercolours fade after drying?

Watercolours are very enjoyable, but right after drying results may not be what you expected: colours changed, faded and become pastel-looking. Why does it happen?

Excessive paint fillers

In a modern world we buy paints at stores and unfortunately we can’t be sure about what’s inside. To increase profits, some manufacturers excessively use fillers. For example, ultramarine may include a lot of clay, yellow colours – chalk, red colours barium sulphate. When water evaporates, chalk layer shows up and instead of vibrant colours we see pastel tones.

For some pigments mineral base may be necessary. Synthetic organic pigments, such as pyrrole red (PR254), Phthalo blue (PB15), Phthalo Green (PG7), as well as bismuth yellos and many others will need a base to show their brightness in full. Like pyrrole red (PR254) without any base will look transparent ruby, Benzimidazolone Yellow (PY154) will not cover paper evenly without a mineral base. So, sometimes, calcium carbonate (PW18), kaolin (PW19) or  Barium Sulfate (PW21) are really good to have, but excessive amounts of these ingredients lead to colour fading after drying. Watercolours in pans tend to have more of them as fillers and extenders, while watercolours in tubes normally contain more glycerine and preservatives.

Chalk in paper

Watercolorists usually prefer cold press, acid-free, 300 by weight cotton paper. These characteristics provide more controllable painting. However, that’s not everything that we need to know. Paper, that we’re buying for watercolour is white. It may be brilliant white or kind of ivory, but anyways – white. This means that fiber was coloured and bleached. Normally, for paper coloration manufacturers use titanium white as the most stable and popular white pigment, but they may add chalk and other components listed above (PW18, PW19, PW21 etc.) that show off through paint layer and cause fading.

Lack of arabic gum

Historically, watercolour binder was arabic gum. It’s a natural sap from acacia trees growing from Senegal on the west coast of Africa all the way to Pakistan and India. Its sap dissolves in water and turns into slightly amber coloured solution, which works as a glue for pigment particles. However, arabic gum is quite expensive and requires some stages of purifying, heating etc. to be used as a binder. As it’s considered to be polysaccharides manufacturers replace arabic gum with dextrine (kind of sugar). Most manufactures claiming that paints have arabic gum as a binder in fact use more dextrine than the gum. 

Dextrine indeed works very well as a glue and creates good adhesion between particles, but it has very poor spreading properties. As a result, watercolours lose their natural gloss and shine and turn into matte and pastel looking surface. 

By adding arabic gum watercolour medium you can improve paint performance.

(c) Rusart

Granulation in Watercolours
In: Paints

Granulation in Watercolours

Watercolour is a very unique medium, and as result we see depends on many factors:

  • paper
  • amount of water used
  • paint quality
  • brushes and
  • mediums.

Today we’ll take a closer look at granulation. 

What is Granulation

Generally speaking, we observe granulation in watercolours when pigment particles don’t evenly cover the paper during or after painting. Granulation implies sedimentation and sometimes flocculation.

These two processes are very similar to each other, but not the same. While the sedimentation occurs when pigment particles separate from each other and naturally fill imperfections in paper or settle down on a surface, the flocculation happens when pigment particles form some random textures and patterns. Heavy mineral pigments combined with high pigment load allow you to achieve both, sedimentation and flocculation.

Why Granulation Happens

Chemistry and physics explain everything. As watercolours (like any other kind of paint) contain binder and pigment, here we get relationship between their masses, particle sizes and densities. When pigment is lighter and finer than the binder we get smooth washes, and when pigment’s particles are bigger and rougher, we get granulation. It happens because binder can’t hold particles well together and water that we use during painting breaks the adhesion between them.

What Pigments are Granulating

As rocks, metals, and other minerals are usually heavy, natural mineral pigments tend to show more granulation, such as:

  • cobalts blue and green – PB28, PG19 etc.
  • cadmiums ed and orange – PO20, PR108 etc.
  • earth green PG23
  • some ultramarines PB29
  • Siennas and umbers PBr8, PBr12, PY43 etc.
  • Oxide iron black PBk11
  • Van Dyke NBr8

PBk11 shows very strong granulation that explains this pigment’s use in many mixes to achieve granulation properties. For example, in such mixes like Payne’s Gray, forest green, deep blue or deep brown colours.

Also, paints made from semi-precious stones are very granulating, such as malachite, lapis lazuli, sodalite, serpentine etc.

For the smoothest washes man-made synthetic organic pigment would be the best choice. Their particles are so fine that a lot of milling cycles required to achieve good bond between the particles and a binder. Here are some examples of smooth (non-granulating) pigments:

  • phthalo blue and greens PB15, PG7
  • Pyrrole red PR254
  • Hanza yellow and orange PY65, PY3, PO5
  • Quinacridones, including reds and magenta PR122
  • Perylene Red PR149
  • Alizarin Crimson NR8

As you could notice, bright yellow and red colours are normally smooth, while blues and blacks have naturally more granulating options. 

How to Increase Granulation in Watercolours

There are many ways how to show more texture in your watercolours:

  • Use more water. As water dilutes binder using more water provokes sedimentation
  • Add granulating pigments. Adding colour containing PBk11 while mixing will increase granulation
  • Use textured paper for sedimentation and smooth paper for better flocculation. As heavy particles tend to fill the gaps and holes, pigment will settle down in “dents” in paper. To show flows of particles we should use smooth paper to direct the paint.
  • Add granulating medium

Experiment with your paints to achieve desired appearance. Most of RUSART Naturals watercolour paints are granulating as we prefer non-toxic mineral pigments for our paints when it’s possible. If mineral pigments are toxic or not ethically sourced we use synthetic man-made pigments. 

Oil Paint Fillers
In: Manufacturing

Oil Paint Fillers

What do you really need to know is that oil paints have a lot of fillers. It’s not possible to make thick paints without them, especially for some synthetic pigments (see other articles). Also, some mineral pigments due to their weight separate in oil paints and some agents needed to prevent this (read Why Oil Paints Separate? article).

The main reason why manufactures use fillers is increasing paint’s volume and reducing costs to maximize profits. For example, student grade paints may contain just 3 or 5 percent of pigment by volume (information taken from safety data sheets, when such details were disclosed). However, it is possible to make paints without fillers and achieve richest chroma. 

Anyways, let’s take a look at fillers and what they do as well as how to recognize them in your paints. 

Barium Sulfate (PW21)

And the champion here is Barium Sulfate (PW21). It’s one of the cheapest (10-25 times cheaper than pigments) and most efficient fillers as it increases opacity and adds some weight to a tube making it feel as if it has higher pigment load. Barium Sulfate is a white crystalline odourless solid, naturally occurring as the mineral barite. It’s insoluble in water, so it is safe to use. However, poorly made synthetic Barium Sulfate may have free soluble barium compounds as impurities that are very poisonous. Most paint have synthetic barium sulfate as a filler.

Aluminium Hydroxide (PW24)

For synthetic pigments Aluminium Hydroxide (PW24) is a very common filler. Sometimes it’s not even considered as a filler for such pigments as phthalocyanine blue or green, pyrrole red, and other synthetic pigments that are super strong and need a base. 

Chalk (PW18)

Chalk (PW18) is also a very common filler here. However, this group is very broad that goes from actual chalk to marble dust. Marble dust brings viscosity to oil paints. As its oil absorption is very low (just 10 g per 100 g) it’s added a lot as a thickener and stabilizer.

Kaolin (PW19)

Kaolin, or PW19, is another common filler that is used a lot in oil paints, especially for titanium white and ultramarines. Chemically speaking, Kaolin is Aluminum Silicate Hydroxide, and more practically it’s just a clay. It has a lot of applications in different areas, including cosmetics. Most face masks, for example, have kaolin as a base. For art supplies, gouache paints as well as pastel, primers etc. may include kaoline as well. Generally, it’s a very safe ingredient, but doesn’t add any value to paints, mostly just increasing the volume of paints.

Why oil paints separate
In: Paints

Why oil paints separate?

Most oil paints separate and there are many reasons for that, good and not really. There are few myths around it, that I (Elena Nahum Leroy) am going to start with. I’m working with oil paints as an artist, tester, seller and manufacturer, so I have a good chance to get full oil paints experience from different sides.

Myths about oil paint separation

Myth: Oil paints separate because they are old

Truth: Separation in some oil paints can start as soon as in a few days after they are made. 

 

Myth: Oil paints separate because pigment is heavy and it sinks to the bottom of the tubes

Truth: It’s partially true. Some mineral pigments such as titanium dioxide, cobalts etc. are really heavy and it’s a challenge to keep them “floating” in the oil without “sinking”. However, in a modern paint technologies a lot of pigments are manufactured and in fact much lighter than oil and separation still happens there. 

And now, real reasons…

 

Oil paint separation from deep inside

Oil is a quite complicated medium. I’d say it’s the most sophisticated art medium that I’ve ever used and tried. Apart from most of other mediums, painting in oil requires knowledge of chemistry and painting technologies to succeed. History knows so many examples of oil paintings made even by great and famous artists that were ruined with time because of wrong application. We’ll talk about that too, in other articles. Now, back to the point.

Generally speaking, oil paints have binder (oil), pigments (natural or synthetic), most likely will have fillers, and may have gums, solvent, beeswax or other additives. And separation can be caused by reaction between any of these components. So, even at this point it’s clear that everything is much more complicated than it seemed before. We’ll cover just most common (not all) reasons for separation in oil paints.

Wrong pigment/binder proportion

If you mix pigment with oil that wouldn’t be enough to create good oil paints, because the pigment is not connected to oil yet. We need to apply pressure and physically bind pigment and oil together with a muller (hand-processed) or a roller machine (industrial method). Some pigments require 5 or even 8 cycles to bind with oil properly. And here we have the first reason of separation.

Different pigments have different oil absorption rate. For example, titanium white takes up to 30 g of oil for every 100 g of pigment, while pyrrole red absorbs up to 70 g for every 100 g of pigment. That’s their normal absorption rates. 

However, even the same pigment may have different grit for a reason (read about that in our special topics). And finer pigments require more oil to fill gaps between finer particles to create proper binding and make paints look and feel smooth and even. But absorption rate remains the same, it’s chemistry. So, in fact we have to add more oil than needed and then we have to remove this extra oil. Else, extra oil will separate from the paint with time.

Why oil paints separatePoor grinding

Another very common reason for oil separation is poor grinding. Different pigments require different number of grinding and milling cycles and even if oil-to-pigment proportion is observed well, insufficient time of grinding may cause quite fast separation.

Weight of pigments

Some pigments are much heavier than oil. These include titanium dioxide, cadmiums, cobalts and some mineral pigments extracted from semi-precious stones, such as lapis lazuli or amethyst. With no fillers added they will separate naturally and this doesn’t mean the paints are bad. However, to create a better look, these pigments will be most likely “diluted” with fillers to create smoother consistency that, when properly done, will technically prevent separation.

Why oil paints separateFillers

However ,the leadership in separation causes belongs to fillers. Oil naturally makes colours look brighter that creates a temptation to add a paste, colour it and sell as a tube of oil paints. This temptation goes stronger, when legislation doesn’t  to disclose the full list of ingredients. As a result, some paints (student grade) have just 3-5% pigment load, for example. 

Barium Sulfate is most popular filler for oil paints due to its low cost and physical properties. First of all, it’s very heavy, which makes it the perfect adulterant for oil paints. Due to its weight Barium Sulfate make tubes feel heavier simulating a high pigment load. Also, its oil absorption rate is just 11, meaning for 100g of the powder we’ll need just 11 g of oil to create a good mixture. So, added to synthetic pigments Barium Sulfate will take extra oil and make oil paints look thicker, imitating higher pigment concentration. That’s another thing that buyers love – thick paints.

However, this trick also have a flip side. Barium Sulfate is very heavy and settles down dragging pigment with it and causes separation. 

So, there could be many reasons why oil paints separate and separation is not always a sign of old or poorly made paints. Test paints, compare them and choose the right ones that work better for your goals. Price here is not always the main indicator.

least toxic art medium
In: Paints

Interesting Facts About Art Materials

Which medium has the highest pigment load? 

If we are talking about professional grade art supplies where the maximum pigment load achieved, soft pastels will be champions. It doesn’t mean that all pastels have higher pigment concentration, but, assuming zero fillers used, it is so. 

Technically, pastel will have pigment and binder, dried to their optimal stage. That means little pigment particles glued together. The softer the pastel the less “glue” is inside and the higher pigment used.

Some artists even use top-grade pastel to make their own watercolours or fresco paints: pigment load in pastels can achieve more than 97%.

The second place would belong to watercolours, that’s why volume-wise professional watercolours are so expensive. Pigment load here can be as high as 92% by volume.

Then goes oil with 88%, and then acrylic, gouache and other paints and mediums go.

What is the least toxic medium to use?

Generally speaking the safest medium to use is watercolour. Provided they contain no formaldehyde or other harsh chemicals as preservatives (read our article about how watercolours are made) or no cadmium or cobalts as pigments watercolour’s binder has mostly food grade ingredients: such as arabic gum, honey, glycerin, dextrin and corn starch. 

Then casein paints go and the third place belongs to artist-grade solvent-free and alkyd-medium free oil paints. 

Oil pastels or oil sticks are quite safe to use, but they may require solvents for spreading that can be very toxic.

What about acrylic paints, most of them contain ammonia and/or solvent to improve spreading quality. Even though acrylic paints are easy to use and clean, working with them should be performed in a well-ventilated area.

Soft pastels are one of the worst mediums to use, because of the dust. Most mineral pigments can be quite toxic when go to your lungs. Especially those that contain cobalts and cadmiums as well as oxides of heavy metals (titanium, zinc, iron, chromium etc.). Also, artists tend to hold crayons as well as smudge pastel drawings with fingers that create direct contact of pigments and skin. All artist-grade pigments are very fine and can penetrate inside the body through the skin.

Which medium is the oldest one?

The oldest medium seems to be charcoal that we can observe in cave paintings dated back 45,500 years. 

Although watercolour-like paintings were found in southwestern France, dated back to 15,000 BC to 9,000 BC, watercolours that we know require paper as support and arabic gum as a binder. Papyrus was invented in Egypt about 3000 BC, while gum Arabic (or gum acacia) can be traced back to about 2650 BC, when it started to be used in the preparation of inks, watercolors and dyes.

Milk-based casein paints has been used since ancient Egyptian times, roughly 5-6 thousands years ago. They apparently didn’t last long and couldn’t be used in commercial manufacturing. In 1930’s  a new water-based casein paint was developed with the use of synthetic rubber and styrene. 

Painting on wood brought egg tempera to the world. The great Byzantine tradition of tempera painting was developed in Italy in the 13-14th centuries by Giotto. Famous icons were painted in Europe and Russia using egg-tempera. Egg tempera was a primary method of painting until after 1500 when it was replaced by oil. 

Oil paints created absolutely a new era in painting and brought us Jan van Eyck, Leonardo, Caravaggio, Rembrandt and many-many other great artists. However, Europeans were not the first who used oil as painting medium. Caves in Afghanistan, near the Bamiyan buddhas which were destroyed by the Taliban in 2001, contained even earlier oil paintings, dated to around 650 AD.

How To Read Paint Labels
In: Paints

How To Read Paint Labels

That’s very important to know what you’re buying and some information about your paints is available on labels:

  • paint name
  • grade
  • pigment used
  • binder
  • lightfastness
  • transparency
  • safety note

Paint name

Although there are many common names for paints we used to see around, there is no standard on how to name a colour. The spectrum contains millions of colours and all they can be named differently. 

Some manufacturers use traditional and most common names, such as cadmium red medium, cobalt blue, ultramarine blue etc. These names stand for pigments used and it’s easy to understand what is inside the tube.

Some names can be unique due to marketing goals or multiple pigment used. For example, Australian Grey or Australian Leaf Light by Art Spectrum or Portland Grays by Gamblin or Raw Umber Leningrad by Nevskaya Palitra. 

Also, the same pigment treated differently can provide a wide verity of hues, shades and transparency level. One of champions in that is PY42 Iron Oxide Yellow ,which has about 100 different names.

Paint grade

Paint grade is also a very questionable category as there is no standards of marking paints student or artist grade. For RUSART, we split paints into 4 categories: children, student, artist and professional. Most manufactures offer 2 categories: student and artist grade.

The main difference in paint grading is pigment load, quality of pigments used as well as fillers and mediums added.

  1. Children grade. We have a special article about art supplies for children. Generally speaking, the main criterium here is safety. Pigments used here are non-toxic and must have certain certification and labelling. Normally we talk about watercolours here and they contain a lot of dextrin (sugar) and starch instead of more expensive components.
  2. Student grade. Safety is not the main criteria here. Usually these paints lower budget for everyday use and practice. Pigment load normally lays between 3 and 20%. All the rest are fillers and binders. Cobalts and cadmiums are normally hues here, which means not real. Although professional artists prefer to use higher quality brands, student paints are still very helpful for underpainting and sketching due to there lower price.
  3. Artist and professional grade. That’s the main target for professional artists. Binders and pigment load vary, but most paints still contain fillers. If earlier information on pigment load was available in safety data sheets, for now it’s hard to find real numbers. According to our experience, pigment load in artist grade paints is between 15-70%. We will talk about pigment load in a special article.

Pigment used

One of the most important information for colour choice. Paint tube will indicate colour index (CI) that stands for chemical characteristics of pigment used. CI will start with N or P. ’N’ stands for ‘Natural’ and ‘P’ stands for ‘Pigment’. Then a colour identification comes: 

  • Y – Yellow
  • W – White
  • B – Blue
  • Br – Brown
  • Bl – Black
  • R – Red
  • V – violet
  • G – green
  • O – Orange

Index doesn’t show exactly the colour or a colour wheel. For example, PR101 is rather red-brown than bright red or PY42 is ochre but still refers to yellow colours.

Then index itself comes. It’s just a number. You can check pigment index names and their technical characteristics here >>

Transparency

This normally has 3 categories: transparent, semi-transparent and opaque. Usually manufacturers include a symbol – a square. If the square is empty the paint is transparent, if it’s half-filled – semitransparent and if the square is black the paint refers to opaque category.

Lightfastness

Nowadays that term is getting replaced with weather resistance, meaning how much paint will change its colours with time under different conditions: exposure to light, UV, moisture, temperature etc.

Safety note

Working with some pigments may involve some risks. For example, cadmiums and cobalts are known to contribute into cancer development. Emerald green (PG21) is extremely toxic and poisonous. Once used as a rat poison and to preserve wood. It was called a trendy color that killed many in victorian society. 

Some other pigments, such as zinc white, can be harmful for environment and are not supposed to be disposed into water or soil. Paints intended for sale in the USA should have safety warning for such pigments. In Canada paints may or may not contain such warnings.

And some other things that you should keep in mind:

  1. Not all ingredients used in paints will be on the label
  2. Term ‘acrylic emulsion’ or ‘acrylic dispersion’ combines many chemical ingredients, including ammonia and solvents and these ingredients will not be listed separately
  3. Oil paints may contain lead or barium sulphate fillers that will not be shown on the labels either
  4. Manufacturing date is normally absent on paint labels

As you can see, labels can give a lot of information on what’s inside. However, some very important things can be still omitted.

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