safe fixatives for tempera and acrylic?

acrylics shouldn't need fixing

tempera - I've never used this on canvas - is it still 'liftable' with water? or has it been fixed by mixing with the acrylic? if it has then it should be stable, if not then the work remains vulnerable to damp.

You could use clear acrylic varnish - matte would be my preferred choice as I really don't like gloss varnish on paintings. If the tempera is still liftable though this may spoil the painting and care would need to be taken.

hope this is of some help

I do egg tempera on board or illustration board. ill use a gesso and then wont use a fixative cause they usually dull the highlights. i have no experience in acrylics or tempera on canvas. Im gonna listen in cause we need a good art line in which to congregate and discuss a possible new trick.

i await someone else , who, like vivien, has skills.

Maybe you could use a spray fixative? I have never used tempera on anything I would care to preserve so i'm not sure how it would react. If it is still water soluble then a spray would probably be safer than a 'brush on' type that would cause smudging. Just make sure you hold the can about 15" away from the artwork and 'mist' on the fixative one layer at a time and let each layer dry completely before moving onto the next.

I'm afraid that I must too defer to someone with more knowledge.

A fixative is something meant to be sprayed on charcoal, pencil or pastel work -- charcoal being the most likely to smudge. This is as uninstrusive as possible and isn't meant as a final protective coating in lieu of glass. These works should always be framed with glass or plexiglass. Dried tempera is only somewhat effected by moisture -- rubbing it with a damp cloth would come up with some color and but unlikely smear the paint unless a lot of pressure were applied. The same acrylic clear spray in any finish from matte to glossy will protect both the acrylic and tempera paints and there should be no problem with tempera on a canvas substrate. Thinned tempera, BTW, is the usual medium for frescos.

the reason I asked about the tempera maybe 'lifting' when dampened was because some tubes of 'tempera' are in fact gouache - so do be careful and check.

LW's explanation is good

Gouache is highly concentrated pigment in a heavy binder very close to the viscosity of oils and mainly used by illustrators or other commercial art applications. The binders for gouache are mostly synthetic. The one warning about goache would be to not use any expensive sable brushes as the high pigmentation is like sandpaper and eats the sable hairs. Tempera is much thinner and usually comes in jars unless there's a product of which I don't have any current knowledge. My art teachers didn't let us use any pre-mixed tempera. We learned how to mix pigment into the egg. The use of the white only gives one a more transparant glaze kind of medium and is Atkins diet approved...

...well, the whole egg is to be honest although this is only information for those who lick their brushes.

What about us cholesterol compromised painters?

Simple -- don't lick the brush, JL. That goes for the oils, too, as they are still toxic. Casein may be okay. I think we could actually milk this one to death.

cheeeez

spray varnish
yes, I have done a "book" with facing pages of pure gouache paintings. I thought that perhaps, although I haven't tried it yet, that fixing it with "fixative" for drawings or a spray varnish would work.
I don't think you should use anything that you brush on, even if you did mix the gouache with the acrylic.

Welcome to a2k, ben. Glad to have you here...

Although gouache is fairly durable it can be scratched and get soiled. I'd use a clear matte acrylic varnish.