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Richeson Casein: Frequently Asked Questions

 

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CASEIN HISTORY

WHAT WAS CASEIN ORIGINALLY USED FOR?
Paint made with Casein was originally used in a gouache manner, simply opaque or somewhat impasto for mural paintings and frescoes, but the strength of Casein as an adhesive made that its primary function. Recipes for the use of adhesives made from casein, or curd, date back to the 11th century.

The perfection of tubed Casein colors during the early 1930's provided artists with the perfect complement: a water–soluble paint that could be used in place of or in conjunction with oil colors. In the 1930's, buildings were painted with Casein, and during World War II it was used for camouflage. Ready–to–use Casein wall paints were popular during the 1940's and 50's. No other media has been so versatile for so long.

CASEIN VERSATILITY

WHAT ARE THE ADVANTAGES OF CASEIN?
Casein differs from other media, yet it shares many of the same characteristics, which make it a very versatile medium that lends itself to many techniques. Casein has the wash capabilities of watercolor, the smooth opacity of tempera and gouache, and the richer textures of oils and acrylics. It always dries quickly to a velvety, matte finish and over time, it becomes resistant to moisture. Unlike oils, Casein is a clean, water–soluble medium requiring no strong solvents. And because it dries quickly, it's possible to lay on a glaze and move onto the next stage within a few hours instead of waiting for days, or even months, for oil glazes over oil to dry. Acrylics can become gummy and resinous unless you buy retarders and mediums. It can also gum up your brushes, making fine detail hard to achieve. Brushes dipped in Casein keep their finesse, producing clear, crisp lines.

I'VE DECIDED I DON'T LIKE SOMETHING IN MY PAINTING. CAN I CHANGE IT?
That's the beauty of Casein. It's correctable! Rub or scrub the area with a damp cloth, paintbrush, or an eraser. If it's dry, with a mixture of ammonia and water (one part ammonia to nine parts water.)

WHAT IF I WANT TO USE A COLOR THAT'S NOT AVAILABLE IN THE SHIVA LINE?
It's simple. Mix Shiva Casein Emulsion with powdered pigments: Spray some water on your palette and scoop out the pigment with a palette knife. Mix thoroughly into a paste and add a few drops of Shiva Casein Emulsion. Mix again, and you're ready to paint.

IS CASEIN ARCHIVAL?
Yes. Properly done and with a protective varnish, Caseins can last longer than oils, especially oils on canvas. They will not crack or yellow.

CASEIN PAINTING SURFACES

WHAT SURFACES MAY BE USED WITH CASEIN?
Casein may be applied to any rigid non–oily surface such as canvas panel, illustration board, heavy watercolor paper, wood panels, masonite, or canvas, or linen mounted on masonite. Casein can also be applied to metal, sheetrock, cement, plaster, wet or dry lime walls and for decorative purposes on glass.

CAN I PAINT WITH CASEIN ON STRETCHED CANVAS?
Yes, but you must remember to paint very thin because Casein can crack if it's applied too thickly. If you would like to paint thickly and would still like to paint on canvas, mount the canvas or linen on masonite, and prime the canvas with PVA, glue or acrylic gesso. Then go to town and paint as thick or thin as you please!

WHAT KIND OF WATERCOLOR PAPER IS RECOMMENDED FOR CASEIN?
Heavy, rigid paper, 300lbs. and up works best. The heavier weights will not ripple when a wash is applied.

WHAT GROUNDS CAN I PAINT ON?
Rabbit skin glue, PVA, glue size and acrylic gesso. Just make sure there's no oil in the grounds.

CAN I USE CASEIN FOR PAINTING A MURAL?
Sure, but only if you're painting an inside mural. For outside murals, you'll have to use specialty paints. Although Casein becomes resistant to water over time, the elements would take their toll.

CAN I USE CASEIN FOR PAINTING FURNITURE OR WALLS?
For furniture, clean the wood and size it with PVA glue or gesso and paint away. For walls, prime them with gesso, or better yet, use Zinzer Bullseye Primer Sealer.

CAN I USE CASEIN ON DIMENSIONAL MATERIALS?
Casein can be used effectively in collage and mixed media applications. It is also widely used for painting scenic and scale models. Casein's soft, natural finish gives miniatures a life–like appearance. Acrylic matte medium over the dry miniatures provides a final protective coating.

CASEIN AND ARTIST'S MEDIUMS

WHAT KIND OF VARNISH SHOULD I USE WITH CASEIN?
Varnish is a matter of preference. Shiva Casein Varnish or a gloss varnish will intensify the color. Using a matte acrylic varnish will preserve that "authentic Casein' look.

WHAT'S THE BEST WAY TO APPLY VARNISH TO CASEIN?
If you brush varnish over a painting with delicate glazes, some lifting may occur, especially if your brush is too course. If you've painted relatively thick, brushing on varnish will work if you're careful. However, the easiest way is to use spray varnish or Shiva Casein Varnish in a spray gun or an aerosol can. Start the spraying process before the nozzle is over the area to be varnished and apply it in a diagonal direction over the painting, spraying in light, quick trails. Let it dry and repeat the process until you have the effect you want. When spraying varnish, open a window and always wear a HEPA rated double filter air mask. When you're finished, leave your studio until the fumes have cleared out.

DOES CASEIN EMULSION INCREASE ADHESION? DOES IT AFFECT DRYING TIME?
Casein Emulsion does have an effect on Casein paints as it increases adhesion and slows down the drying time.

ARE CASEIN PAINTS SOLUBLE WITH ALCOHOL?
No, not with alcohol. However, you can easily lift up mistakes by using ammonia. Generally, a 1:9 ammonia and water mixture will be what is needed.

 

CASEIN PAINTING TECHNIQUES

WHAT KIND OF BRUSHES SHOULD I USE WITH CASEIN AND HOW SHOULD I CLEAN THEM?
You can use almost any kind of brush depending on the effect you want to create everything from stiff white brushes to soft hair watercolor brushes, oil brushes, Chinese brushes and fine points for tempera style. Or, if you really want to get crazy, use all of them together. Because it dries quickly, Casein can be hard on brushes, so make sure you clean them thoroughly with gentle soap and water or a commercial cleaner when your painting day is over.

CAN I MIX AND MATCH CASEIN WITH OTHER MEDIA?
You can use Casein directly with watercolor, gouache and acrylics. With oils, use Casein for underpainting or apply it after you've applied an intermediary varnish.

HOW CAN I PAINT IMPASTO WHEN IT'S NOT RECOMMENDED FOR CASEIN?
Casein paints are in fact fine for a moderate impasto. To achieve a heavy impasto, it is recommended that you paint your impasto texture first, using thick gesso and a rough bristle brush. Then paint with Casein on top in the normal, liquid way.

IF CASEIN IS OPAQUE, HOW CAN IT BE USED FOR WASHES?
Casein is opaque, especially when white is added. However, when it's diluted with water, it can be applied in translucent layers, creating a gauze–like effect.

WHEN CASEIN DRIES, THE VALUES SOMETIMES SEEM SLIGHTLY DIFFERENT FROM WHEN THEY WERE WET. WHAT CAN I DO ABOUT THAT?
Mix the color you want and apply a swatch on the area you want to paint. Then use a hair dryer to dry the Casein quickly. If the color's okay, go ahead. If not, remix it and try it again until you're satisfied. And don't worry that you have swatches with the wrong color, because with Casein, it's as simple as painting over all the areas you've tested. After you've painted with Casein a while, you will learn which colors lighten and darken by instinct. And remember, sometimes happy accidents "wake up" a painting!

SOMETIMES WHEN I USE LAYERS OF CASEIN, THE COLORS SEEM TO LOOK MUDDY. WHY IS THIS HAPPENING?
Applying too many layers of color or not allowing them to dry thoroughly may mute or muddy colors. Speed up the drying time with that handy hair dryer.

WHAT IS HALFTONE BLACK?
Even though Casein colors like titanium white and ivory black are opaque, halftone black is finely dispersed, allowing your underpainting to show through. When applied over another color, the color changes with incredible results. For instance, when you put halftone black over burnt sienna, you'll get a beautiful purple. Halftone black is also great for shading over flat areas of color.

I'VE HEARD THAT YOU SHOULD ADD WHITE TO CASEIN WHEN USING IT AS A WASH. IS THIS TRUE?
Adding a touch of white to your Casein colors will help you control your washes. Five percent white will make washes lighten gradually from opaque to transparent instead of changing too rapidly. Try it, you won't believe the difference!

CAN I USE CASEIN FOR FRESCO PAINTING?
For Fresco painting, Casein colors are thinned with water and applied to cement or lime walls, either wet or dry. The color should be of thin consistency.

CAN CASEIN BE USED WITH RESIST–INK?
Some of the most exciting textural and tonal effects can be achieved using this technique. Basically, it involves nothing more than brushing waterproof black ink over a Casein painting. The greater the variety of surface textures, the more intriguing the results. Making sure the paint is completely dry, fill a soft brush with the ink and stroke it over the picture. It can be very black or diluted to different intensities. While it is drying, the ink will be absorbed into the areas with the thinnest coats of paint. The more thickly laid textures will repel it. When it has dried, run it under the faucet with cold water and allows the ink to wash off. It will leave a mottled half tone effect.

WHAT KIND OF WATER SHOULD I USE WITH CASEIN?
Some people recommend distilled water, but ordinary tap water seems to work just fine.

CASEIN VS. OTHER MEDIA

HOW DOES CASEIN DIFFER FROM WATERCOLORS?
While watercolors are transparent, Casein is essentially opaque. The main advantage of Casein over watercolor is that it's so easily correctable. It can be removed with a cloth, brush or eraser, or if it's already dry, with a cloth dipped in ammonia and water (one part ammonia to nine parts water.)

HOW DOES CASEIN DIFFER FROM ACRYLICS?
The general characteristic and appearance of acrylic paint is bright, bold color, stretching flatly across the canvas. Casein is often described as quiet and subtle, having a color depth similar to oils. While some acrylics can be used to produce a non–gloss finish, it is still different from the matte finish of Casein. Also, Casein can be used in mixed media techniques where acrylics cannot: as an underpainting for oil or mixed with watercolor.

HOW DOES CASEIN DIFFER FROM GOUACHE?
Gouache is similar to Casein in that is an opaque medium that can be thinned with water, but unlike Casein, it cannot be reworked once dry.

HOW DOES CASEIN DIFFER FROM EGG TEMPERA?
If compared to egg tempera, the differences seem to deal with ease of use. Casein, which comes in tube form, is much easier to use than the complicated formula for egg tempera. Egg tempera also can only be worked on in small areas because of it's quick drying time, while Casein brushes on more smoothly and dries much less quickly.

CASEIN CARE

DOES CASEIN HAVE A SHELF LIFE?
Casein paint tubes may harden a bit if they aren't handled frequently. Squeezing the tubes circulates the emulsion with the pigments, keeping them moist and pliable.

SHOULD I REFRIGERATE OR FREEZE MY CASEIN PAINTS?
For a short period of time (like overnight) you can put them in the refrigerator to keep them fresh, but never put them in the freezer. Unlike other paints, Casein cannot withstand freezing temperatures, which will rupture the emulsion film, causing a breakdown in stability.

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