Gloss varnishing without glare

[Raymond Smith]

I've heard of an varnishing technique called 'museum finish' which is a clear gloss finish that won't matte down dark colors. I suspect it's a way of slightly abrading the dried varnish so that it doesn't reflect the light as strongly. I intend to use Gamblin varnish, and would rather not add beeswax to matte it down, as I suspect it will cloud any dark tones. Does anyone have any advice on this?
Thanks!

[Chris Saper]

Hi Raymond,

Hopefully one of our tech guru members can offer information - the only thing I can offer is that I use about 2 tsp of Gamblin's Cold Wax medium dissolved in one jar of Gamvar, because I like to cut the gloss of the varnish, and prefer a litlle more satin varnish. It doesn't cloud the darks.

[Richard Bingham]

The "museum" or "gallery" finish for final varnishing refers to the method of applying it. A good brush is required (preferably a 2" badger-hair sash brush) and (minimal) skill using it. Varnish is applied with the painting laid horizontally; when the varnish reaches a certain "tack", it's "laid off" by manipulating the brush (using the very tip), and that results in an "upset" finish that diffuses reflection, unlike the glassy-smooth surface that normally results when varnish "flows out".

The final varnishes of choice used to be damar and mastic. Combining the two, 50/50 or with a reduced portion of mastic (to taste) prrovides a varnish that's very agreeable to apply in this manner. I expect numerous posts will follow, relating the pernicious and inferior qualities of both of these natural resin varnishes. Indeed, the modern synthetic final varnishes currently being offered are no doubt much superior to these obsolete, antiquated materials, if not perfect, and it's best to relegate damar and mastic to the dustbin of history, as curiosities, along with many other materials which have made up the pharmacopiae of oil painting through its 500+ year history.

Whether the handling character of "newfangled" varnishes is conducive to laying off a "gallery sheen", I do not know . . . I haven't gotten around to trying 'em yet.

Applying any non-reflective coating is problematic for the presentation of a painting at its intended full contrast and chroma, since reducing glare (even by reducing gloss by laying off a "gallery sheen") can only be accomplished by breaking up the light reflected from a surface, and all additives, whether wax, silicates or inert ingredients, impart a milky look to dark passages to some extent.

If the new synthetic varnishes are compatible with beeswax , (i.e., if the mfgr. recommends adding it) it's the best choice for making up a "matte" varnish. Experiment to arrive at a mix which reduces glare acceptably with the least amount of wax.

[David Clemons]

I believe the origin of the controversy with a gallery finish is related to a practice by the National Gallery in the 19th century to add a varnish mixture that included boiled linseed oil and litharge mixed with mastic. The oil content in the varnish was the issue.

I've managed to get a similar effect when applying a glossy spirit varnish (MSA.) Essentially, it's just a matter of disturbing the surface with the brush tip, as Richard mentioned, without resorting to using matting agents, although, I've done that too.

[Raymond Smith]

Richard-I believe what you've described is the technique I must have read about somewhere. Whatever it was, it also mentioned that 'people don't take the time to do this anymore.'

However-this forum is the place where 'people do take the time!'

I will try the laying off technique. I assume that the strokes should be at right angles to each other, when the time is right.

Chris-I am also going to try the beeswax technique. My concern here is that I've read (in Mayer, pg 241) that adding wax to a natural resin solution causes 'the dried films (to) will be tender and susceptible to polishing.' Have you found this to be the case with your synthetic (Gamvar) finishes?

Richard & David-is there a 'wait time' window you can recommend for the varnish to sit before I do the dragging?!

Thank you all for your time and attention!

[Richard Bingham]

Hi, Raymond ! I can only relate what I have found through experience. As noted above, the varnish of choice may or may not be "ideal", and other materials ultimately may be found to be superior. I like a 60/40 proportion of damar and mastic, both varnishes at a 5# cut (i.e., the resin crystals dissolved in good pure spirits of gum turpentine to the proportion of five pounds to the gallon) before mixing them.

Damar retouch varnish sold in art stores is too light in solids; damar alone "flashes" a bit too quickly to manipulate in this manner. You may encounter some difficulty obtaining Chios Mastic (resin of the pistachio trees peculiar to that Greek island (pistachia lentiscus). Looking for it through ethnic food suppliers is a better bet than art materials, it is used in Greek pastries.

It's more difficult to work very large pieces, (over 3' in one dimension) because the varnish may reach a tackiness conducive to "laying off" where you began, before you've applied varnish to the whole thing, so you need to keep working across, following up as needed.

There is no specific time factor, all depends on temperature and humidity where you are working, and the absorbency of the painting being varnished. Apply the varnish sparingly, working it well into the surface, and . . . just keep brushing . . . as you return to the areas of initial application, eventually you'll note how the brush begins dragging, and this is the time to "lay off" the sheen . . . a light source oblique to the surface of the painting is useful, so you can see "wet" areas, and the results of your "distressing" the finish as it tacks up.

I don't follow a specific pattern for brushing, obviously it's more effective to follow a regular pattern so as not to leave "holidays". Something of a random pattern of overlapping strokes works well for me. Keep the varnish brush perpendicular to the surface, using only the flagged tip of the brush. This is why a badger brush is especially nice to use, and a fair-sized one (2") at that . . . makes it all much easier!

At least in theory, this technique could be employed with any varnish at the point of "tack", but success will depend on each varnish's open working time, how rapidly it reaches that point, and whether it is formulated to flow out rather than "stack". Last, as Dave points out, the "bad press" the Nat'l Gallery varnish got was for using a varnish that would not be readily re-soluble and hence, removable. Don't try anything for a "final varnish" that contains drying oils, or forms an insoluble film. Good luck!

[David Clemons]

Originally Posted by Raymond Smith

... I assume that the strokes should be at right angles to each other, when the time is right...

That's the general idea. Lightly drag a dry brush across the inital layer of gloss varnish at a right angle to distrupt the gloss sheen. You won't get a matte surface, just less glossy. You only need to wait a few minutes for some of the solvent to evaporate, and keep the brush dry. Test it on a scrap with dry darkly painted areas to get the hang of it.

[Raymond Smith]

I can see that the size of the piece would also be a factor. I have a large 36" X 60" painting that i've wanted to varnish, but held off until I felt informed.
It's my 9/11 painting, and it's full of darks.

Thanks for your highly informed advice, guys!