Question About Casein?

[prospector]

I bought eight tubes of Shiva casein for their matte finish. Other than that what is the advantage of casein; say over acrylics for under paintings for oils?
Can you use casein and acrylics togeather to make them water proof when dry, and still have a matte finish?

I would also like to use casein in plein air work. Does casein dry lighter, or darker. I tried acrylics in plein air work but did not like their drying darker than what I applied. Dont mind the fast drying time. It forces me to get my values, and hue right on the pallet and keeps me from piddling with it on canvas. I learned speed to be the key in plein air painting, but found the collectors prefere oils over water base mediums.

All comments welcome.

[Richard Saylor]

Casein gets brittle with age, so if it is used for underpainting it is best to use a rigid support. Also, the paint film is somewhat absorbant. It might be best to apply a coat of clear shellac (or some kind of fixative or varnish) before applying the oils, but I'm not sure about this.

I think the casein and acrylic binders are compatible, but I've never mixed them myself. A casein painting becomes very water resistant after curing six months or so. I found an old, very dirty casein painting in my attic. I washed it with soap and water without any damage to the paint film.

The few casein colors I have (red, blue, yellow, white) show very little value shift as they dry, but that's under artificial light. Whether they shift significantly under natural lighting, I don't know. I'm sure Jamie knows.

Richard

[dbclemons]

Originally Posted by prospector

...Other than that what is the advantage of casein; say over acrylics for under paintings for oils?

The main benefit casein has over acrylic is that it's absorbancy also allows for a chemical bond with the oil, rather than only the weaker physical type that acrylic offers. The medium also can be used as a water and oil emulsion for making an underpainting oil wash that dries quickly and holds very well. I prefer this method over using solvents. You can also make a traditional style gesso with casein and whiting as you might with hide glue. Because of it's absorbancy, you do need to size the surface properly beforehand if you use oils with them. The casein can suck the oil into it as you paint over it, so I sometimes place a thin isolating layer of shellac over it first, which also keeps the pigment from lifting.

Originally Posted by prospector

...Can you use casein and acrylics togeather to make them water proof when dry, and still have a matte finish?

Both of these can be mixed together and will be waterproof. Casein takes a long while for the curing to happen; acrylic is waterproof in a few minutes. You could use a matte medium to reduse the glossiness of acrylics, or use acrylic gouache which is more matte than the paint.

Originally Posted by prospector

...I would also like to use casein in plein air work. Does casein dry lighter, or darker...

There tends to be a shift to a lighter value when it completely dries, mostly if you add more medium. If you use just straight paint and water the change is not as noticeable as long as you keep your values in proportion. Casein stays "open" longer than acrylics, so you can re-wet the paint with water or more paint for a longer period of time.

[staggerlee]

Here is a link I found exceptionally helpfulwhen I bought my first Shiva's:

http://www.johnmolnarpaintings.com/p...tiscasein.html

It was a good starting point for me, not knowing a thing about the medium, and when I wrote to him through his site regarding some further questions about casein, he wrote back in length answering them...

A fun tip from him: Weldbond glue, use it as a sealer for panels/adhering canvas and as a medium along with casein (in limited quantities).

Worth looking into, his site, for info and his work is amazing.

[prospector]

Richard, That is the kind of info I was looking for.

Dbclemons. Thanks for the great re. It helped me a lot. Going to try casein on an underpainting for an oil landscape I have in mind.

Staggerlee. Great links. I saved em to my favorites

Hope to post results of my under painting soon.

[Jeanne-M Turner]

I have been busy experimenting with casein paint and love the fluidity. Similar to Guoache or poster paint, it behaves just as I would want but leaves a permanent finish when dry.The problem is th I am not satisfied with the varnish that I use is the Acrylic based varnish I have uesed and I assume that Shiva casein varnish is the best. Before I order some can anyone else have a better suggestion please?
Jeanne-M Turner. France.

[dbclemons]

The general recommendation is that casein or gouache paintings not be varnished at all, but only framed under glass when completed. The reason is that varnishes are designed to be removable should the surface ever need conservation care, and with casein or gouache that couldn't be done safely. Whatever you used would become a permanent part of the painting.

Shiva's casein varnish is essentially shellac, but many types of shellac don't age well and become discolored or brittle.

If the acrylic varnish you've used is a mineral spirit varnish, that to me has more advantages, but it's still not removable in this case. Also both of these can often cause a value shift in the pigments to occur after they're applied to casein.

[Glazer86]

I love painting but have grown frustrated with my chosen medium, oil. I am about to order a set of casein paints, and while I am at it, I want to order some good brushes to go with.

I have always painted thinly, and I don't see why that would change, but I don't know what kind of brushes would be suitable for this with casein.

Could someone with a little more experience in this medium than myself recommend a style of brush? IE synthetic like I would use with acrylic paint or perhaps more of a watercolor/gouache style of brush?

Thank you for your time and answers.

[sansnom]

If you paint thinly, softer brushes are probably what you want to use with casein. Casein can be used like watercolour, and in fact I have done casein paintings that were assumed by viewers to be watercolour!

One point that probably needs to be made is that it is very important to clean your brushes soon after use. Since casein eventually cures to a waterproof state, you really want to remove any traces of the paint from your brushes.

Personally I would not use my (expensive!) Kolinsky brushes with casein, but I guess it depends on your bank balance and cleaning skills whether you do or not

Of course, you can also use hog bristle brushes or synthetics with casein - what you use depends on how thickly you paint, but also on whether you want brush stroke effects to show in the result. Impasto is not really an option with casein, unless it is quite thin and you paint on a solid support. Heavy impasto will crack, and casein is fairly brittle, so painting on a board is a good idea. Stretched canvas is not a good option for casein.