finish for gouache?

[tensai]

i checked the ray smith artist handbook but cant seem to find any information on putting a finish layer on gouache.

do people just leave it as is? after finishing photographing i would like to protect it from dirt etc.
so, if you would like to put a finish on it could you use acrylic gloss varnish (realize you loose the matte finish), and how about matte varnish?

any info greatly appreciated.

edit: matte medium doesnt seem to work on water based mediums. i read something about using gum-arabic. is that only usable as medium while painting or can it also be used afterwards?

tensai

[Elwell]

Generally guaouche, like watercolor, is left unvarnished. Varnishing destroys the velvety matte surface gouche is known for, and can cause dramatic value shifts. And, because the surface is absorbent, any varnish becomes part of the paint layer and can't be removed at a later date. Since almost all resins, even synthetic ones, yellow to some degree over time, this is a potential problem. However, if you wanted a glossy, saturated surface, or you needed to seal the paint so it could be worked over with oils or acrylics, I'd use a non-removeable acrylic clear coat like Krylon Crystal Clear. Be careful to use it with proper ventilation, though, as it's pretty nasty stuff.

[tensai]

thanks elwell, i thought/hoped you might reply as you seem to have done in the past with similar questions as well.

so how do you hang these guys? i dont want to put this stuff behind glass. if you dont, how do people clean it over time? just with a dry duster or something?

also ive used cold pressed 1mm illustration board. i hardly thinned the gouache with water but the board is bent. any idea on how to counter that without cracking the paint?

many thanks,

tensai

[dbclemons]

Sorry to reply to an old thread, but I just caught this. I wouldn't bother with mounting it behind glass unless it's spaced properly to not tough the paint surface. For my own, I usually just matt them or also add a frame, but no glass. There are special gouache varnishes available, but I wouldn't recommend it for the reasons Elwell mentions. I clean cloth or duster should keep them clean enough.

The bowing issue can be altered a bit by gessoing or adding a layer of acrylic medium to the back, and placing weight on the sides or corners while it dries. Kind of pulls it back into shape.

-David