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Phil Coleman
02-09-2013, 07:08 AM
When using Gouache is there anything which can be brushed are sprayed on to parts of the painting so as not to disturb it with applying further layers. Often when applying additional layer i have disturbed the underlying paint, there have been times when i would like to retain those lower layer so have considered trying perhaps an acrylic mat medium, perhaps a spirit based mat varnish or even ateliers acrylic fast medium/fixer. What have you used and how successful has it been?

Thanks

Steve Orin
02-09-2013, 08:19 AM
Not all guache is the same... Some have more plasticity. Makes them more resistant to "lift". I've messed up a few times by letting my love for texture cause me to over-wet underlayers & see them lift off. Had to go back after scrubbing off the loose stuff & rebuild with thin layers. As a rule though, I like the ability to lightly scumble undercoats into next ones. You? If I didn't I'd go back to oils or acrylics. Anyway, I have experimented with topcoating finished paintings, trying to lessen their weakness. By spraying very lightly I've applied several coats of acrylic clear but had to go so slowly that the water could not sink into the paint & cause problems. It worked but the appearance changed just enuff that I decided to not do so again, without due cause. Paintings loose a certain softness when cleared.

meglyman
02-10-2013, 01:22 PM
Lifting is a "feature" of gouache that varies between useful and hair-tearing annoying. Some brands and pigments take layering better than others. If your first coat is more of a wash, it can take a bit of abuse. If it's thick, I've only ever had good results with a very light, dry-brushy top layer. Like Steve, I tried spray fix on it and the results vary. It might work fine, but you might end up ruining it - once I had to repaint every dark part of the painting because the fixative gave it white spots. And I've never tried painting over fixed gouache to know whether it would even help with the lifting... I say experiment! :)

Phil Coleman
02-15-2013, 04:28 PM
Well! I have had a play with several of the varnishes i had together with one just bought and also tried a light coating of Gum Arabic. The most successful coating was provided by Chroma's (Ateliers) invisible solvent finishing varnish, It is very thin and dried with the minimal colour shift and was almost invisible. It offered quite a bit of protection against scrubbing so i will keep this on hand should i ever wish to protect specific areas of my paintings.
Others tried included Winsor and Newtons mat solvent varnish which was rather thick and actually dried with a slight sheen, Ateliers fast medium/fixer and Ateliers Mat medium/varnish.
Since experimenting with the above i also tried using Ateliers interactive acrylics in conjunction with the Gouache (I know this is classified as mixed media and may be frowned upon by many but still), i really liked this combination since this brand of acrylics can be kept open almost indefinitely by lightly spraying the surface. It allowed me to blend the gouache into the more robust acrylic film but most exciting of all was the effect achieved by using the water spray upon the Gouache. It allowed me to bleed the Gouache in a sort of loose watercolour style whilst retaining the acrylic layers but even then, the acrylic film could still be blended into the bleeding Gouache since it does not dry like conventional acrylics.

dbclemons
02-18-2013, 09:04 AM
There are several brands of acrylic "gouache" paints that behave similarly to actual gouache but are more water resistant. That should allow you to avoid using an isolating coating of any kind such as a varnish.

I have been able to add layers of wet gouache over previous dried coats by using a very soft brush with long hairs and a light touch. This can be done even with water-thinned paint, but it takes some practice.