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Tag Archives: RUSART Naturals

How to use copal medium in oil painting
In: Practice

Copal in oil painting

There are many different kinds of additives and enhancers exist for oil painting (including copal resin) and all they have their own use. In general, we can identify 6 kinds of materials that can be added to oil paints. All they have different purposes and use.

Oil paint main chemicals:

  • different kinds of oil (linseed, walnut, poppyseed etc.)
  • Natural resins, rosins and gums (turpentine gum, ambers, copal, dammar etc.)
  • Synthetic resins (alkyd)
  • Solvents (white spirit, turpentine oil etc.)
  • Waxes 
  • Essential oils

Let’s talk about copal resin and medium based on this gum. Based on our researches, old masters, including Leonardo, were using a lot of different mediums, experimenting with oil paints. One of them was amber. 

Amber varnish for painting

Amber varnish is one of the oldest ones. People from Ancient Egypt used it for tombs. They preheated amber composite with torches or iron and then polished to desired shine and transparency. In Renaissance times amber varnish were also in a wide use to add some strength to painting film. With the time heating got replaced with chemicals and instead of melting gums, manufacturers started dissolving it with white spirits and turpentine oil.

However, amber is quite expensive ingredient. You can tell it looking at prices of jewelry that contains amber. So, artists were in search of a less expensive substitution to amber and found some other resins that work similar. And one of the was copal. 

Copal as an amber substitute

Copal is resin extracted from trees in the Burseraceae family, that provide many other kinds of intense resins, such as frankincense or myrrh. Polymerized, these resins provide qualities close to amber. 

Copal, apart from other resins used for oil painting, penetrates inside painting layers and forms one substance with it. This property makes oil film (after drying) stronger and more resistant to chemicals, moist and other environmental influences. Also, it brings more elasticity to a layer making it resistant to physical damage. Just add some of copal medium to your paints.

Leonardo da Vinci used copal gum mixed with sunlight bleached walnut oil as a painting medium, in search of perpetual varnish. And RUSART recreated one of his recipes of copal oil medium based on manuscripts found.

You can also use copal medium as varnish, when applied on top of your painting. However, restorers don’t like that as copal varnish is not removable and seals your painting for good. So, if any restoration will be needed, it cannot been performed. So, use copal as a painting agent, but avoid using it for top layers to prolong time of your artwork.

(c) Elena Nahum Leroy

Choose your perfect oil for painting
In: Paints

How to choose linseed oil for painting?

How to choose oil for painting is the most common question for artists, both beginners and professionals. Trying and choosing right materials determine how long your painting is going to “live” and your painting experience.

What artists are looking for in oil?

When I start talking about oil as a binder for arts, I’m getting many questions from why not to use cooking oil for painting to why oil costs so different in stores. That’s a very broad questions and I’ll give all the answers in this and other articles. But let’s begin with the beginning – what are we looking for in “ideal oil”. This concept will help us choose the best oil for painting.

What would be an “ideal” best oil for painting?

  1. Ideal oil should dry fast – you want to continue layering as soon as possible while your inspiration is still with you. You don’t want to wait for a week or longer
  2. Ideal oil should be thin – you’re using oil as a thinner for your paints. If you need to change oil texture in any other ways, there are other mediums for that.
  3. Perfect oil doesn’t yellow with time – you want to make sure that your work will remain as you painted as long as possible.
  4. The best oil for painting is not reversible – that means that after drying it’s stable and permanent and will not melt and turn back to a semi-liquid form under different temperature or humidity conditions.
  5. Ideal oil provides good adhesion – layers of paint should stick to canvas or other support and to previous layers without a risk of peeling off.
  6. Perfect oil for painting doesn’t form cracking – of course, you don’t want your painting to get cracklings. If you want this “antiqued look”, there are some special mediums for that.
  7. Ideal oil has matte finish – that’s not about tastes, that’s about practical aspect. Glossy finish is fine when you work in “alla prima” techniques, i.e. paint wet-on-wet with 1 single layer. In this case selection of mediums may be broader. However, if you work in multi-layering technique, only final layer should have gloss as glossy layers do not “glue” to each other. In other words, whatever we paint on top of glossy layer sooner or later will peel off. And “later” here is less than 5 years.
  8. Ideal oil doesn’t contain toxic chemicals – if you’re sensitive to solvents and other chemicals or work in a small space with poor ventilation, you may prefer a safer options.

We hope all these help you choose the best oil for painting. Of course, “ideal oil” doesn’t exist, but we can try to get closer to this ambitious goal.

Why refined, bleached and thickened linseed oil?

Why I chose linseed oil for painting you can read in our other articles. They explain benefits of each kinds of oil. Let’s assume that we’ve chosen linseed oil and let’s find out the processing methods that make the goals of “ideal oil” real.

  1. Drying time

    Initially, extracted oil has many components inside, from different acids and vitamins to proteins. All they are good for our health when consumed, but do not work well for painting. Some raw oil components make oil sticky, increase drying time and show low transparency. That’s why cooking oil doesn’t work for painting. It simply has a goal to provide our body with nutritions, which should be removed in painting purposes. So, the first thing to choose in oil for painting is the indication “refined”.

  2. Consistence

    Most oils that just extracted have thicker texture than desired for painting. That’s why oil needs to be refined.

  3. Yellowing / non-yellowing

    Most oils for painting have yellow colour and due to some acids that linseed oil contains this kind of oil yellows with time on your painting. That’s why bleaching is a necessary process, which can be done naturally or chemically.

  4.  Adhesion

    For a better adhesion linseed oil should be thickened. In can be done in different ways or their combinations. Normally, this includes temperature and air or vacuum conditions.

  5. Ideal oil is not reversible

    The best oil for painting should stay stable and permanent after drying, meaning the oil will not melt and turn back to a semi-liquid form under different temperature or humidity conditions.

  6. Matt finish and permanency

    Due to linseed oil key characteristics, if it’s not stand oil or if there are no resins added, linseed oil provides matte finish and non-reversible.

  7. Toxicity

    Refining, thickening and bleaching takes long time. And, of course, manufacturers want to speed up to gain greater profits. And there are many technical and chemical methods to do so. Some producers are “cheating” adding solvents or turpentine in oil to make it look more transparent and reduce drying time. However, some chemicals may cause headaches and other health issues for sensitive people. Also, turpentine and white spirits, for example, require a good ventilation to use.

How Elena’s Signature oil made?

Elena Nahum Leroy (Perelman), the only owner of RUSART, recreated naturally treated linseed oil recipes that artists were using in Russia throughout generations, until the new mass-production era began. Read what she’s saying about oils.

Elena used traditional recipes that artists were using for most precious works in Russia. Yes, it took almost a year to produce a batch, but it definitely worth it.

  1. Raw cold-pressed linseed oil was naturally refined 3-5 times with water to remove protein and slime. We have to say, it took 2-3 weeks depending on quality of initial oil. And we drained about 20% of oil by volume. It’s not because the oil was “bad”, it’s because the oil has tons of stuff good as food or for wood-working purposes, but not for painting.
  2. Then we slowly heated the oil for 15-20 hours to remove water residue, polymerize and thicken. It’s a very delicate process as if a temperature is too low nothing is going to happen, and if it’s too high, oil will boil and obtain amber colour.
  3. Then we filtered the oil  2-3 times to finish refining and remove residue of sediments.
  4. And the last step – we exposed the oil to the sun for 9-12 months for bleaching.

So, we used no harsh chemicals, just power or water and the sun. That is a traditional Russian recipe of oil preparation for painting used for hundreds years.

Buy Elena’s Signature Linseed Oil >>

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