Paints in powdered form require the addition of a liquid to prepare them for use. The manufacturer's directions as to the amount of oil, varnish, water, or other vehicle required should be followed.
One precaution: You can't paint with it in cold weather. The chemical reaction that transforms the water solution into a durable finish will not take place if the temperature is below 50°. (Conventional oil paints don't stick well in cold weather, either.)
Water-thinned interior paints are calcimine, casein, resin-emulsion, and gloss water paints. Calcimine consists of powdered whiting and clay mixed with an animal-glue binder and a preservative. It cannot be recoated, but can be easily washed off before redecorating.
Primitivist (naive) artists depicted objects in a solid monumental manner, as seen by a child who perceives the world as a whole, without analyzing it and breaking into unnecessary components.
Suppose it rains while you're working? Vinyl paint dries fast - as quickly as 10 to 30 minutes - and will withstand a shower after that time. It takes another 12 hours to "cure," by then forming an exceptionally tough, long-lasting film that stands up well against weather, sun, salt air and factory smoke.
Knock down texture is basically a orange peel that is sprayed on and allowed to "set-up" for a minute or two then gently "knocked down" by running a 6" drywall knife over it, "knocking down" the surface of the texture. Although knock down is a flattened version of orange peel, I suggest you do not use a spray can of orange peel, the knock down comes in its own spray can and the results are much better, again experiment before spraying it on the wall. However, If ever you apply any of the textures to the wall and are not satisfied with the results, wash the texture off immediately before it dries, then allow the wall to dry and try it again. Once you have the texture applied to your liking and you have allowed it to dry, you may want to paint the patches a couple of time before painting the entire wall, especially for walls where the paint to be applied will have some sheen. Multiple coats on these areas will make them blend in, unnoticeable, with the rest of the wall. You will know if the patches need more coats of paint, because the patch/texture will have absorbed the paint causing the spot to look duller than the rest of the existing wall.
Traditionally, the solvents or VOCs and other chemicals used to make paints easier to apply give off toxic fumes that seep into the atmosphere for years after application. Paints with reduced or no VOCs are healthier for decorators and the people whose homes are painted with them.