I was visiting the club layouts at the McCormick Stillman Railroad Park in Scottsdale, (well worth the visit–10,000 sq ft of O,HO,& N layouts) and was talking to one of the guys there. I mentioned I was having trouble blending the coloring of my Hydrocal and Sculptamold, and he raved about using an overcoat of Gesso. Said it will take paint and stain equally well. Any thumbs up or down from the fellow forumites?
I’ve not used it, but it should work. Gesso is used by painters as a “primer” on the canvas so it takes paint well and evenly. It should work pretty much the same on plaster and Sculptamold.
Matte medium will work similarly.
One reason for using it to cover everything is that it evens out the ability of the base materials to absorb pigments. For example, hydrocal is more dense than patching plaster, so if you have an area with both of those materials and then try to apply stains and pigments, they won’t be the same. Cover it all in gesso, and it will take stain equally. Same thing if you put an overall coat of pretty much anything over the base materials, just so there is a uniform surface to color. Not sure why you’d pick one material over another, other than gesso should be very good at taking carved in details as well, and is goign to be smoother than some other options.
–Randy
Best thing abou Gesso is, if you mess up painting or tinting your scenery, just paint it all over with Gesso and start all over again!