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Tag Archives: tempera

water based paints and water soluble paints
In: Manufacturing

Why water-based paints are not water-based

Now we can see more and more labels saying “water-based paint” or “water-based varnish” or “water-based medium”. In fact, only few kinds of products can be truly called “water-based”. Let’s look inside “water based paints” meaning.

Why company use “water-based” for their labels?

All these comes from the times when acrylic paints started to appear on the art supplies market and when a massive campaign against oil painting began. Wherever possible acrylic paint advocates poured a bucket of dirt on oil painting manufactures claiming that oil paints are toxic, not safe, and acrylic paints are much better, because they are water-based. Then the market was roughly split into “toxic oil-based” products and “safe water-based” ones with the big lie started.

Now manufacturers have many reasons to call more and more products “water-based” because:

  • “water” means natural and “water-based” attracts customers
  • “water-based” is a clear statement and easy to understand
  • labelling paints as “water-based” is a simple way to stay apart from alcohol- and oil-based ones.

Water-based vs water-soluble paints

A true meaning of “water-base” is a mixture or solution of pigment, dye or tint in water. We use these fluids for tinting plaster, paper, gesso or primer and other mediums. You can find tints at our shop too.

Manufacturers also use pigments dissolved in water for fresco painting, where wall plaster serves as a binder. For any other cases we need a binder to “glue” pigment particles together and keep them attached to a support, such as paper, canvas, wood etc. Binder is a base for any paint. So, water based paint meaning is very narrow. And talking about “water-based” paints we should rather say “water soluble” paints.

Water soluble paints include a very wide range of products:

  • watercolours (based on Arabic gum)
  • acrylic paints (based on acrylic dispersion or emulsion )
  • Latex paints (based on acrylic resin)
  • Water-soluble ink (based on acrylic dispersion)
  • Gouache (based on Arabic gum or acrylic dispersion)
  • PVAc tempera paints (based on poly vinyl acetate)
  • Casein paints (based on casein and oil)
  • Finger paints (based on dextrin, starch and other sugar-glue binders)

As you see, a spectrum of “water-based” paints is very wide and it doesn’t always mean “water plus pigment only” pair.

Potential other ingredients for water-soluble paints

Depending on kind of paint and its intent to use paints will have some other components beyond just binder:

  • Fillers – to make a tube look bigger and replace expensive components like pigments
  • Enhancers – to make paints spread easier, enrich colours or achieve other properties, like opacity/transparency, increase viscosity, add gloss or matt finish, reduce or increase drying time and other
  • Preservatives – to prevent mold growing and extend shelf life
  • Humectants – to prevent paints from drying 

And here we can find some harmless components, such as honey, clays, marble dust, corn syrup, starches, dextrin, essential oils, resins, silica, glycerine etc. 

On top of those paints most likely will contain one or more of those: isopropyl alcohol, white spirits, solvents, ammonia, formalin, phthalates, xylene and other.

Always check list of ingredients, especially if work indoors. Manufacture safety data sheets do not disclose all information.

You can read more about different ingredients of paints and how they contribute into your art and your health in our knowledge base. And get updates to your email with our newsletter.

Metallic acrylic paints by RUSART Deco and Tempera PVAc paints
In: Paints

PVAc Tempera Paints for Artists: Use, Comparison to Acrylic and Benefits

Generally speaking, tempera is not just one kind of paints. “Tempera” is a term that describes many paints with pigments dispersed in an emulsion miscible with water. So, technically, acrylic, watercolours, gouache, PVAc paints are kinds of temperas. However, for some reason we use word “tempera” only for a certain kinds of paints.

Polyvinyl Acetate, or PVAc paints, actually, are ancestors of well-known and widely used in North America acrylic paints. “Ancestors” doesn’t mean that acrylic paints are better than PVAc tempera. But due to many factors tempera was replaced with acrylics.

PVAc paints vs. acrylic paints

  1. As any other kind of paints, PVAc tempera contains pigment powder and binder. Paints may and do contain other ingredients, such as fillers, additives, preservatives, colour enhancers etc., but let’s omit these components as they do not ermine the key characteristics of paints. As you can guess, tempera has polyvinyl acetate as a binder, while acrylic paints have acrylic dispersion, emulsion or resins inside.
  2. PVAc tempera usually much lower in VOC than acrylic.
  3. Normally, PVAc tempera has no ammonia vs. acrylic, where ammonia is used to increase adhesion and performance.
  4. Acrylic can be either opaque or transparent, while tempera is normally all opaque.
  5. They both can use water as a thinner
  6. Tempera works best of all on wood. Historically, egg-tempera was used in Olden Russia in painting icons. Of course, pigment blended with egg-yolk has a very short shelf life that makes it impossible in mass-production. PVAc tempera has the closest properties to original egg tempera. Check legendary Russian iconographer Andrey Rublev.
  7. Drying time for both acrylic and PVAc tempera is similar.
  8. They both change colour after drying, when water evaporates.
  9. Acrylic can dry matte, or gloss, or something in between. PVAc tempera is always matte.
  10. Although both acrylic and PVAc tempera form permanent film, acrylic has better permanence compared to tempera.
  11. Tempera’s binder goes inside the support leaving pigment “glued” to a surface. Acrylic paints form a film. That’s why sometimes acrylic is peeling off.
  12. Acrylic paints have much broader use: from canvas and paper to fabric and glass.  Tempera’s use is quite limited (see below).
  13. Both PVAc and acrylic paints form stable and water-resistant film after drying. However tempera is more vulnerable to moist and freezing temperatures, hence, do not use tempera for exterior art projects and finishing.

How to use PVAc tempera paints?

Use it as any other opaque water-based paint. Tempera works very well on any fibre or porous support, such as:

  • paper
  • cardboard
  • wood
  • canvas
  • drywall
  • plaster
  • plywood etc.

To thin just add some water. You can also use white glue as a medium. However, as white glue is actually white when wet and transparent once dry, it may be challenging to mix colours at first.

Once dries, tempera paints form permanent and water-resistant film. When watered-down, tempera gives beautiful washes just with water with endless possibilities for glazing techniques.

Full drying time depends on amount of water used, but is very similar to acrylic paints. While you paint, your work may look glossy because of the water used. But as soon as tempera dries the surface is absolutely matte.

For your creative projects feel free to add some acrylic or oil layers on top of tempera. After full drying, of course.

Cover your finished works with acrylic or oil-based varnish, but give them at least 48 hours before applying any finishing.

Check our selection of Professional PVAc Tempera Paints >>

 

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