View Full Version : "workable fixative" for gouache?

03-26-2007, 09:38 PM
Is there something that can serve as a "workable fixative" for gouache? By which I mean something I can brush or spray on a gouache underpainting (after it has dried) that has enough tooth to allow a new layer of gouache without any disturbance of the underpainting?

Richard Saylor
03-26-2007, 11:03 PM
Krylon Kamar Varnish is supposed to be suitable for use as a workable retouch varnish for oil, acrylic, and watercolor (and therefore gouache). If I think about it, I'll try using it tomorrow as a gouache fixative. I believe shellac can be used to isolate casein layers, and maybe it would also work for gouache.

03-27-2007, 09:22 AM
Excellent question. After spending hours last night fighting with lifting gouache, I'm eager to try fixatives.

Richard Saylor
03-27-2007, 06:44 PM
The Kamar didn't work. It's too slick. The paint beads up on it. A workable fixative of some sort might work, but I don't have anything like that on hand. By the way, anything which works for watercolor should work for gouache. You might inquire in the watercolor forum.

It is sometimes possible to apply a glaze (translucent layer) over a dry layer, but it is tricky. The glaze must be applied very lightly with a soft brush in such a way that there are no overlapping brush strokes, or else the previous layer will lift.

Another option would be to use an airbrush for the glaze.

In general the trick to overpainting a layer is to keep the brush strokes to a minimum. Any back and forth application of paint will likely stir up the underlayer.

Sorry I couldn't help more.

03-27-2007, 09:48 PM
Workable fixative can be compatible with watercolor and gouache. Some are designed to repel water, however, so check the details on the label. Krylon's or Grumbacher's Myston are two I'd recommend. I have a can of Krylon and it works okay, but gives a slight sheen to some opaque areas. Blick (http://www.dickblick.com/zz217/03b/)lists it as "Matte" but it isn't that matte to me. You can also mask off areas with scratch paper so it doesn't spray where it's not necessary.

Richeson/Shiva makes a shellac based varnish for their caseins that is recommended for isolation layers, so that could work also. Spraying it is less likely to move the paint than a brush.

Richard Saylor
03-28-2007, 03:09 AM
...Richeson/Shiva makes a shellac based varnish for their caseins that is recommended for isolation layers, so that could work also. Spraying it is less likely to move the paint than a brush.Hooray! Shiva Casein Varnish does indeed work with gouache. I tried it. It can even be brushed on without disturbing the paint surface. (Alcohol is apparently a poor solvent for dried gouache.) Just use a single very thin application of varnish so that the painting surface does not become too water repellant. Do not apply your new layer of gouache too aggressively, or it can still disturb the underpainting. The whole procedure is a bit tricky, so I want to experiment further before recommending that anyone buy a bottle of casein varnish.

Richard Saylor
03-28-2007, 03:11 AM

03-28-2007, 11:15 AM
One concern I'd mention about the casein varnish is that shellac is not designed to be stored in a permanent liquid state. It has a natural shelf life of maybe one year at most when diluted in alcohol. Companies like Zinsser sell shellac finishes that they claim can last up to 3 years or so, but not without adding preservatives and who-knows-what. I have no idea what Shiva's recommended shelf life of their varnish is.

All the fixatives I've seen use acrylic resins and some sort of solvent, like acetone, propellents, etc. which dissapate rather quickly.