Faceups Liquitex Sealant and Gouache?

most gouache is like an opaque watercolor. it is water soluble and safe to use. however be careful to let the gouache dry 1000% before you seal, let the sealant dry 1000% before you gouache, and don't apply too much sealant at once. since the varnish is water based, the moisture could smudge your work.
there is also a product called "acrylic gouache." It is not water soluble. it's also safe to use.

 

I actually tried this exact combo yesterday, and it works well. Apply with a (makeup) sponge, not a brush, in many very thin layers, and let everything dry completely before you proceed, just as @Novalyna said.

 

I use this combo and it works, however - make sure the gouache is thinned down with either water or acrylic thinner, applied in thin layers and completely dry before dabbing on the sealant. Raw thick gouache will not dry. If you want to paint a bigger area, like colour match the head, you'll need to switch to acrylic paint.

Good luck with faceups! It's always a little bit of trial and error so I'd recommend getting a variety of materials to see what works best for you!

 

I use a similar sealant. I use Windsor and Newton Matte varnish with a sponge applicator and have had good success, though I’m still very much a novice. Only struggle I have is when you apply it with a sponge it is likely to pick up a bit of pastels. I haven’t tried using gouache so I would follow everyone above for advice.

 

I don’t know if it’s safe to do so, but I’ve used hairspray to keep the pastels in place before sealing with a sponge. It worked out really well and didn’t seem to interact with the Liquitex, but I don’t know if there are any long-term risks to this that could affect the quality of the faceup or the sealant.

 

I have never heard of using hairspray before. Would love to know what kind of long term issues if there were any. I might have to try it just out of curiosity. I have an old doll which I got for free that has become my test/experiment doll since I don’t really have any want for her anymore.

 

@LikablePlatypus - I've only noticed pastel picking up when there's too much of it on one layer - I always give it a gentle blow before sealing to get rid of the loose pigment. The sealant creates kind of a grainy texture that the pastel dust latches onto and the sponge picks up what didn't fit into those crevices. It's less of a problem when using a spray sealant but when you're dabbing over it, you'll have to do it in thinner layers.

If you do pick up some pastel, you can also just cut the dirty part of the sponge off so you don't transfer it back. Hairspray might have some ingredients (human cosmetics tend to include oils) that don't jive well with the materials or resin and it'd be a shame if the faceup falls apart because of it.