View Full Version : varnishing experiments

02-11-2008, 01:07 PM

Today I started a little varnishing/fixing experiment with oil pastels to try out and see how much the op painting is influenced by the varnish/fixative.
The fixatives used in this experiment are (from left to right) Schmincke retouching varnish (as suggested by FJ Bettag), Sennelier oil pastel fixative (yes, I'm using the liquid version of it since I generally don't like aerosols) and an acrylic gloss varnish by Liquitex.


I prepared a canvas and painted four (almost identical ;) ) patterns on them. Top (stripes): CD'A Neopastels : black, ultramarine, lt. blue, veronese green, purple, red, yellow,
Bottom (triangle): Sennelier: delft blue, purple, lemon yellow,
white and black as stripes upon the other colors.

I noticed that I should have waited a little bit more for the colors to set. Especially the Sen purple was very creamy and smeared terribly with the white, turning it into a pinkish color. Unfortunately I tend to be an impatient person, so I just got the varnishes out and started varnishing right away. :D

Guess what happened? Yes, the Sen purple dissolved a little bit in both varnishes (Sen & Schm.). :eek:


The other pastels stayed fine, except perhaps for the CDA ultramarine where I also could witness some slight signs of dissolution.

Well, I've varnished oil pastels before and I never had these troubles, but normally I also wait for about a month until I varnish them. With other words, I'll have to repeat this experiment and this time I'm going to wait at least three weeks. :cool:

02-11-2008, 01:31 PM
Well described experiments, thanks for sharing. I look forward to your next part.

Pat Isaac
02-11-2008, 03:03 PM
Thanks for doing this experiment, Silvia. I'd really be interested in seeing how it turns out. No one has said yet what is the purpose of varnishing between layers. Do you have a suggestion?


02-11-2008, 03:32 PM
I think the idea of varnishing between layers derives from the "soft" pastel concept of using workable fixative to build up complicated layers without disturbing the underlying layer. However, my understanding is that these fixatives also "regenerate" a slight "toothiness" that might be needed for more pigment to adhere. This should be a non-issue with OP since it seems to me that amount of tooth is a less significant problem given the adherent properties inherent in OPs.

Would this make sense?


Pat Isaac
02-11-2008, 03:45 PM
Yes, I have quite a few soft pastel artist friends and that is exactly why they use the fix between layers. I do feel that that is not the case with OPs as I don't think it would create a tooth. The layers work fine and adhere to each other. I'm still nervous about putting anything between the layers. I am going to see if I can find that DVD.


02-11-2008, 03:56 PM
Silvia, your experiments with varnishing will be most interesting to follow. I have the Sennelier spray fixative for OPs but have only used it once as a trial. I would think that using a liquid where you have to brush it on would be much more likely to disturb the surface as you apply it. Jane.

02-11-2008, 06:11 PM
Sounds like a good experiment. I tried varnishing an OP painting a while back with pretty bad results. It was made using super cheap very hard OP's that were more like crayons. I melted them onto WC paper to do the painting. They were hard again as soon as they cooled off. A few months later I tried varnishing it with a brush. Darned if it didn't seem to work for a little bit before total disaster hit. First swipe with the brush was fine, but the 2nd moved the wax around and made a mess. I don't remember which varnish it was at this point, but something with an odor of turps. I guess that shows petroleum based spirits or turps are a good solvent for waxes!

02-11-2008, 10:37 PM
Interesting. Will check back in 3 weeks!:)
In Bill Creevy's Pastel Book,he advocates varnish between layers as a way to get more oil pastel over other coats where it might not otherwise stick. I think he was using a smooth surface, not sanded. I tried it, several years ago before i got any artist-grade o.p.s or sanded paper, and it did help. I was trying to put highlights on dark blue bottles, with cheap oil pastels.There was no tooth at all, though, on the acrylic,but it more or less worked.
I have varnished o.p. pieces with acrylic medium or varnish, nothing important, and they are still fine several years later. If scratched, the acrylic will come off, but I wouldn't want to scratch an oil or acrylic painting either.
If my painting had a lot of turp involvement on thin o.p., the varnish smeared
the o.p.s and ruined the work.

02-11-2008, 11:42 PM
Silvia: Thanks so much for the info you've provided, and for your experiments in varnishing. I'd be interested in seeing what you could come up with if trying the varnishes in isolating layers. This looks like a very good experiment, and well-presented too. I'll also be looking forward to your further experiments, after the OP has had time to surface-dry. Thanks!

I just posted much of this elsewhere (marsias thread), but it seems more applicable here, so I'm reposting it:

I've mentioned before that an OP painting of Susan Bennerstrom's that I saw in a gallery some time back appeared to me to have been done using some sort of isolating varnish between layers, and it was very effective, giving the painting a really wonderful sense of depth. I still haven't tried this yet myself, but would like to someday. There's some earlier discussion here: http://www.wetcanvas.com/forums/archive/index.php/t-392035.html (the thread also has a link to the Oil Pastel Society pdf about framing without glass).

I know that the Sennelier fixative creates a flexible finish surface because it's made with a vinyl resin, rather than acrylic. I think that is what is required for a successful coating for OPs. Acrylic products, OTOH, dry to a rigid finish, as I understand it, so when applied over OPs there's a chance that would lead to problems. Theoretically, at least, the rigid surface of the acrylic would be relatively unaffected by environmental changes, but, because OPs never really dry, there would continue to be movement in the OP layers below. This uneven expansion and contraction of the OP and acrylic varnish layers could result in crazing of the acrylic varnish or in delamination of the varnish surface. (I read up quite a bit on this after seeing that Bennerstrom piece, so this is how I understand it at the moment. I've never experimented with an acrylic varnish however.)

Pat, Jane, it sounds like this uneven expansion and contraction of the layers may have been the problem that Dyin may have had. And yet Creevy seems to have had success. Go figure. I have used liquin with OPs, and found that when it finally started really drying, there was a significant color shift, although that may be an entirely different issue.

Also, I'm still wishing for a varnish/fix for OPs that has a matte finish, not glossy. I find the Sennelier gloss to be down right distracting, and it's hard to get a good photo with such a shiny surface. Upon reading the info that you and marsias provided, I looked around to see if Schminke carried any varnish that could be used with OPs that had a matte (or at least satin) finish, but no luck. Any ideas? Liquitex makes what they describe as a flexible varnish. Is that what you're using, Silvia? I'm very curious, especially as it comes in a matte finish.

There is one other product that looked interesting for possible use with OPs: Maimeri makes an insulating varnish: http://www.lucas-impex.ro/m.aspx?id=37&it=4


A clear, colourless varnish for application over mat colours prior to application of Final mat varnish. Acts as insulation to prevent sedimentation of matifying components contained in products to rise to the surface, resulting in white spots.

Vinyl resin (12%). Alcohols. Acetates. Highly flammable. Irritant.

75 ml, 250 ml, 500 ml, 1000 ml

It was the vinyl resins in the product that made me wonder if it might be useful as an isolating varnish for OP work. I don't think it's carried anyplace in the U.S., that I could find at least. But since both marsias and Silvia are European, I thought I'd pass the info along. I really have no idea if this would really work with OPs, though.

Talens also makes an OP varnish that sounds different than the vinyl resin types: http://www.artmaterialsco.com/product_info.php?cPath=96&products_id=1396
Has anybody tried that one?

02-12-2008, 07:48 AM
hi there everybody, I'm back again. :wave:
I do not have much time now, but I'll try to answer as many questions as possible now.

Julie, thank you very much. I do my best :cat: .

Pat, I also do not really know what varnishing in between layers is good for, but I think that Bill and Wendy gave good reasons. If you're asking why Bettag varnishes in between, well, he does it, because he wants to keep the appearance of his strokes as unaltered as possible - and he does not like to wait for his pastels to set :lol: . (Obviously he doesn't work much with sen purple... :lol: :lol: :lol: )

Bill, thank you very much. Yes; I think the reasons you gave are right.

Jane, yes, it's true. In fact it is a little tricky to apply the varnish with a brush, but it works. The trick is to use a very, very, very, very soft brush and very, very, very, very easy strokes. :lol: I bought myself a set of modelmaking brushes (these brushes are the softest available, they are made for applying enamel) and I grew so fond of them, that I am using them for my acrylic painting, too, especially when working in layers.

Paul, so sorry to hear of the troubles you had with your varnish. It probably was the solvent/turps in your varnish that caused the desaster. As far as I know there are only few varnishes that really do work with oil pastels (or wax pastels). I'm going to try those :).

Well, I have to go back to work now, but I'll be back this evening to answer Wendy's and Annie's posts, too. Stay tuned :D

02-12-2008, 01:26 PM
Wendy, it's good to know that you were successful with the acrylic varnish. I tried varnishing an oil pastel painting with acrylic medium only once - and it was a terrible experience. The surface of my painting stayed sticky for a very long time. Anyway, since there are still many books on OPs around that claim varnishing OPs with acrylic varnish to be possible, I'm going to try that once again.

Annie, yes, I think the acrylic varnish I use here is the same you mentioned (though the colors of the bottle seem a little bit different from those in the picture of the link you posted). I do have the matte varnish of liquitex, too. Actually I could varnish half of the pattern in glossy, half in matte varnish :lol: , but to be true: I do not like the matte varnish very much. It just isn't what I expected it to be and I do not like the surface it creates. So if you like a matte finish, I would rather leave the painting unvarnished.
And yes, this varnish is flexible, let me show you this:

This OP painting on canson paper was coated with two coats of sennelier fixative and then with one coat of liquitex varnish glossy. This was done 3 months ago. I can bend it, I can roll it up - it stays fine. (Perhaps it would not stand crumpling, but then again I wouldn't crumple a painting either.)

By the way, I once tried painting a mixed media kind of painting by isolating every layer of paint (watercolor, gouache, oil pastels, colored pencils, ink) with a coat of varnish. It worked very well and created an interesting look. I did 30+ layers of color and varnish. If you look at the picture it seems very dark, but if you shine on it, it will reveal all the subtle colors that are hidden in those layers of varnish.
This painting taught me one thing: it is important to know that many layers of varnish tend to darken the painting pretty much. (Every oil/acrylic painter who already did a painting in flamish technique knows what I am talking about.)
I'll try to get that maimeri product, too, but I'm afraid that this will take me a while since maimeri is very hard to get.

02-12-2008, 03:59 PM
Silvia: Thanks very much for the information. I notice from the Liquitex blurb (http://www.liquitex.com/Products/fluidmedglossmedvar.cfm) on their varnish, that they say that it's specifically for use on flexible surfaces. Here's part of what they write:

Translucent when wet, transparent (clear) when dry.
100% acrylic polymer varnish. Water soluble when wet. Good chemical and water resistance.
Dry to a non-tacky, hard, flexible surface that is resistant to retention of dirt.
Resists discoloring (non-yellowing, non-fogging) due to humidity, heat and ultraviolet light.
Depending upon substrate, allows moisture to pass through (breathable).
Will not crack as surface expands and contracts during temperature and humidity changes. Applicable for any surface (flexible and inflexible) suitable for acrylic paint and mediums, such as canvas, paper, wood, Plexiglas, etc.
That sounds quite different than other types of acrylic products, which dry brittle, although Liquitex also says that the varnish isn't suitable for use over oil paintings. I wonder why and whether Liquitex thinks the caution should extend to OPs for some reason. It also occurs to me that perhaps there are other acrylic varnish/fixative products that also dry flexible, and I have been thinking all along more of acrylic medium, which tends not to.

Not to worry about making up a matte example, Sylvia. I was just curious. I'm also wondering if mixing the two - gloss and matte - might create a sort of satin finish that might be a happy medium. No need to try that either, though - just a bit of musing on my part.

The image you provided showing the flexibility of the varnish is fascinating. Does application of the varnish make ithe treated OP paintings suitable for framing without glass? It really looks like it may, judging from your image. Very interesting and if so, that's exactly what many of us here have been hoping to find. I'm impressed! Thanks again, Sylvia! :)

Pat Isaac
02-12-2008, 04:57 PM
Can the surface of the OP after varnishing be scratched and ruined? If the surface makes it just like a finished oil that would be great! No glass...


02-13-2008, 04:22 PM
Pat, whether the varnished painting can be scratched will surely depend on what you use for scratching, too. I cannot scratch it with my fingernails (do they count as appropiate testing instrument? :lol: ) and I cannot peel the varnish off (in the way Wendy described). So I think, yes, it is comparable to a finished oil painting. The only thing I am still curious about is to see, whether this kind of varnish will alter the colors in the course of time.

Annie, you're right about mixing the matte with the glossy varnish. This will result in a satin finish, indeed. You can do that, there's no problem.
I'm not surprised to learn that Liquitex does not recommend their varnishes for use over oil paintings, since acrylic medium/varnish won't adhere correctly on an oily surface. Yet it can adhere to the resin-layer that is built up with the Sen fixative (and the Sen fixative again can adhere to the oilpainting - I guess that's the whole secret of this varnishing technique).
Judging from my impressions it is possible to frame a painting that has been varnished like that without glass.

Pat Isaac
02-13-2008, 04:39 PM
Yes, fingernails count. That was what I was thinking of as opposed to a tool.
Thanks for doing this. I will be interested in more results.


02-18-2008, 12:31 AM
No worries Sylvia, I think I learned my lesson on that one. Test first if not sure. Kinda what you are doing actually! :thumbsup: I later repainted that one in acrylics and it came out about the same, so I was happy with that. Maybe if I had sprayed the varnish on with an airbrush it would have been ok, not sure. That's what I usually do since then with acrylic paintings but I haven't tried it with an oil pastel or encaustic type painting yet.

Great job on the testing, it's neat that you are doing this research!