My first layout back in the 60's followed the Linn Westcott methods of hard shell scenery and zip texturing. The hard shell formula called for tinting the plaster with dry powder pigments, in my case, using black to get a medium-light gray base color.
Tinting the plaster has two obvious advantages, as the color is solid, chips in the scenery are less noticeable, and it saves the base painting step.
It seems now that all scenery starts with white plaster, so I'm wondering if this is a preference, or have we largely overlooked the use of tinting?
Jim
I find that tinting plaster isn't worth the trouble. In my own modeling, incidents that cause visible damage to the rockwork are extremely rare. Even with tinted plaster, chips are still noticeable in most cases, so I figure why bother.
I never got the base color to look at all right for what I like to model just with tinted plaster, so painting was always required anyway. It's not a matter of overlooking the "advantages" touted by Westcott, as much as realizing they weren't really advantages for my scenery modeling, and more of a waste of time.
Rob Spangler
I do both. It doesn't take much color to change the plaster from white to tan or gray. It's unlikely to produce the shade of rock color you want but chips will blend in. Once it sets, I paint the rock the base color I want. Over that will go some washes to take the uniform color out of the rock and make it look more natural.
Some recommend a cement dye/tint you can buy at hardware stores such as Home Depot.
I experimented with some zip texture pigments I had but in the end I couldnt be bothered and just used ordinary plaster of paris and simply painted it.
Rio Grande. The Action Road - Focus 1977-1983
When I mix pigment with plaster, the product tends to be uniformly colored. I use this when I want to make "dirt rubble"--I break up and sort it later. I also use it a bit for dirt slopes.
When I apply pigment as a thinned wash over plain white plaster/Hydrocal, the color tends to concentrate in and emphasize cracks and interior corners. Also, more layers can be applied, possibly using different colors. I use this for exposed rock faces.
I haven't painted plaster, though I expect it would tend to be uniformly colored.
Ed
I use Gypsolite as my base plaster. It's gritty and gives a nice rough texture for a natural surface. Unfortunately, it dries a light gray. I tint the plaster before application with a few squirts of brown acrylic craft paint.
I then use a wash of craft paint (sometimes several colors) to get a camouflage effect.
After turf and ground foam are applied in a similar pattern to the paint, the scene looks quite natural.
It takes an iron man to play with a toy iron horse.