Your Casein Questions

When I try out a new kind of paint, I like to use a super-limited palette, as I did on this painting of a historic wooden boatbuilding shop. (Watch on YouTube)

Yesterday I invited you to ask questions about casein, and they were great ones. Here are some answers.

Paint
Elo Wobing: Can I ask why you choose this medium over other water soluble painting mediums? Specifically, why not use acrylic paint which is also water soluble with opaque and transparent qualities?
Elo, Yes, you're right, acrylic is very similar. The stronger emulsion strength of acrylic paint makes is preferable to casein if you want durable impastos. The kind of acrylic I do use from time to time is Holbein Acrya Gouache (which is really acrylic). The thing I like about casein is the weaker emulsion, which keeps the paint from being sticky or gummy as it's drying. Casein flows more readily off the brush than does acrylic.

J. Oates: I am curious too as to why you choose casein over gouache. It is not as readily available as gouache in the UK, and so not easy to try.
Good question. Casein and gouache are very similar, so the lessons in this video apply to both media. I reach for casein when I want a fuller bodied paint, and it's less expensive per cc so I can use it more freely. It also has a more closed surface when it dries, meaning the paint won't be reactivated by a later wet stroke. Gouache is better than casein for fine detail, and gouache offers more color choices, and generally heavier pigment concentration.

Matt Dicke: Do you have a preference of Gouache or Casein as an alternative to oil? There are many times when dealing with solvents is not possible and having a water based medium that has a similar feel and handling to oil is needed?
I would say that casein has more body than gouache, and in that sense, it feels more like oil. Maybe it's also that the paint tubes are the same size as oil, and I use plenty of paint when I'm using casein. Casein doesn't really have the impasto quality of oil, though, and neither does gouache. Also, neither gouache or casein has the transparent deep darks of oil. They both dry light in the darks, and that takes some getting used to.

Gary: Is it advisable to order an additional, larger tube of Titanium white with the casein sets? In some media (acrylic gouache) it is difficult to paint opaquely without it.
Yes, I think it's a good idea to have one of the larger tubes of white. I go through two or three times more white than any other color.

Keita Hopkinson: From your experience, how fast does casein dry... (whether a wash, or opaque passages)? Thanks much!
Since it's an aqueous medium, drying time depends on the heat and humidity, as with watercolor and gouache. It will dry to the touch anywhere from a few seconds to a minute or so. Casein is unusual in that the proteins in the milk emulsion continue to strengthen after the paint has dried to the touch, so after a few days or weeks, it will be tougher than paint that has just dried.

Matthieu Kiriyama: I wish I could put my hands on some casein paint, but it doesn't seem like they're available here in Japan (A set of 6 colors from Richeson sells for a hefty 100 to 180 dollars on Amazon). Is Richeson the only manufacturer you know of that I could look into? I understand that milk paint is a popular medium for painting furniture, but not every brand is suitable for fine arts? (I have the same problem of not being able to buy your new video with Paypal the way I did on Sellfy before.)

Richeson is the only manufacturer of tubed artist grade casein that I'm aware of. They bought the Shivá company, and make the same paint under the two different brands. If casein is not available in your area, no worries. I would substitute gouache or Acryla gouache. Here's a previous post about gouache materials. And sorry about the Paypal issue. I've been having difficulties uploading the files to Sellfy and Cubebrush, but I'll keep trying.

Color Palette
Koushik: 1) How do you pick a limited palette a priori? For instance, in the painting at Lowell's, you picked a very low chroma yellow palette (with black literally being the cool color). Do you decide up front which gamut you're going to use, pick suitable primaries, then interpret things within that range? As in, you could just as well do your fall Wyoming painting (Torrey creek) using say, a strong blue, a cool red and a muted yellow (like ochre)? I'm just asking because I'm trying to understand how you fix your color gamut without any pre-mixing by limiting your pigment choices.
Good question. I don't follow any set rule. I'm usually pretty intuitive about palette choice. But as I think about it, there are three common circumstances that determine my decision of a given limited palette.

1. One is simply what I have in my paint kit. I often bring a random choice of white plus a red, a yellow, and a blue, trying to choose a version of those colors I haven't tried in a while. That's how I recently fell in love with Perylene Maroon, and Prussian Blue in gouache.

2. Another circumstance is when I have a preconceived color (or lighting) idea and I don't care what the actual colors are in the scene in front of me. That was the case with the painting of the solar flare effect, which I wanted to look like my memory of a photographic lens flare.

3. The third circumstance is when I look at a given scene and I try to identify the main color notes that reappear in the scene or that are essential to it. I try to boil those down to about six or fewer colors and set those out as tubes on the palette. If I need a "spiker" color or "guest" color (as I call them sometimes) I can bring them in as an extra spice.

Varnish and Mediums

Garin Baker painting with me (in oil) at Lowell's Boat Shop

Koushik: 2) You mention varnish in the section on birch panels. You appear to be using some sort of brush-on varnish (made by Richeson I presume) for your finished pieces. In one of your earlier posts on GJ you've mentioned trying the Richeson varnish on paper and having it soak into the surface repeatedly. How would you varnish something that is painted on say, illustration board? Does the clear coat spray work better instead? Additionally, how long do you wait before varnishing (with either brush-on or spray)? I know the emulsion strengthens with time - even though the surface is dry to touch, Richeson says it might take several weeks before the paint film completely sets!

Yes, I was using the Richeson varnish, applied with a brush. But I have also tried Krylon Crystal Clear. Both tend to get soaked up into paintings done on absorbent paper or board, so for those substrates, it can take over four coats before you start seeing much gloss or darkening of the darks. Even if the varnish soaks in, it's important not too use too much with each application.

A surface sealed at the beginning with gesso or acrylic medium or a thick layer of casein that fills the paper's pores would allow the varnish to float on the surface more. It's probably a good idea to wait at least a week or two before varnishing. 

Margaret Berthold: I'm having trouble varnishing casein paintings on 140 pound Arches watercolor paper. When I spray on a gloss varnish, some areas remain matte and some are glossy. It's very patchy and it seems no matter how many coats I apply it won't acquire an even gloss. Would sealing the paper help? With what? Or is a different surface a better idea?
Yes, as mentioned above, if you want the glossy look of a finish, try to prep the surface at the beginning to make it less absorbent. Two things to add: don't use anything with oil on any layers below the casein, and consider leaving the casein unvarnished. The matte surface can be very attractive.

Technique

Jeff Allen: When painting the water, would the same layering technique apply as casein, paint the light 1st, then the dark?
I'm not completely sure I understand your question. Since it's an opaque medium, you could proceed in various ways—light first, then dark; or dark first, then light. Or area by area. My general approach is to wash in some light tones, work the big masses of tone and save the lightest, darkest, and finest accents for last.

John Berkey

Hypnopoodles: Do you know of any great works of art done in casein? And on another note, do artists ever work large with gouache and casein? I'm not sure I've ever seen a gouache painting spanning several feet 
John Berkey comes to mind (above). Casein has been used a lot in theatrical set painting and Medieval portable altarpieces, and in some murals, so certainly it can be used large. Below is a casein painting by Samuel Colman.

"Solomon's Temple, Colorado"
20.5" x 26" casein on canvas
Samuel Colman Jr. - 1888

 Links and resources

"Casein Painting in the Wild"
HD Digital download on Gumroad (Credit cards)
HD Digital download on Sellfy (Paypal) Buy now
DVD at Kunaki (ships worldwide) or Amazon
Casein Explorers Pack (12) (A good introductory palette that gives you pretty wide gamut.)
Casein 6 Pack (The colors I used for this painting. On its own, it's a rather muted palette. It makes a good supplement to the 12 pack.)
Casein 6-pack with travel brush set (Same set as above with the short-handled set).