Friday, June 11, 2010

A little more about varnishing paintings

Above are damar tears as the crystals are called. They are the exudate of dipterocarpaceae trees which grow in East Asia and India. When dissolved in turpentine they form damar varnish. Utrecht sells a nice package, pictured below that comes with a big teabag full of the tears, you add turps, let em soak, and in a day or so you have lots of affordable varnish. Great product! This is a great buy if you make your own varnish and oil medium too.

Utrecht Ready-to-Make Damar Varnish for Oil Painting, 10.5 oz can

Utrecht Ready-to-Make Damar Varnish for Oil Painting, 10.5 oz can Utrecht Ready-to-Make Damar Varnish for Oil Painting, 10.5 oz can
(Item No: 27101)
Bulk Discount


I was asked;

"So my gallery wants a nice even finish, like that of a varnished piece, on every piece going up on the walls. How do I get that if I am not to varnish a piece for 6 months to a year after I finish it?"

All galleries want that. Here's the best suggestion I can give you. I don't think there is any great harm coating the paintings with Liquin but I think a better fix is to spray them with retouch varnish after they have dried for a day or two. DO NOT use enough that the varnish pools on the surface of your new painting, otherwise it may actually dissolve the paint. This problem goes away after the painting is dryer but I advise you to never let that happen.

It is best to do that in a couple of thin applications. But this is only temporary and the painting should be final varnished at a later date. Several commenters have asked me how I deal with that. The short answer is, often I don't. This is a problem I have discussed with my artist friends and they all seem to do about the same thing, retouch and then out the door. I cannot possibly sit on all my work for a year and then varnish it.

If I do get a chance to varnish a painting that hasn't sold or I am visiting a client who has one of my paintings I will varnish it. I do that with a brush and with the painting lying flat. Keeping it thin is good too, pools of varnish will show on the painting. Matt varnish is a crime against nature. It KILLS your color.

I am thinking that I will write up a page to be included with the painting in an envelope that is stapled to the stretchers describing to the client that the painting needs to be varnished and how to do it. When I do I will publish it to the blog so you all can copy it of and use it too.I often don't know who has my paintings as they are sold through dealers.


Chris said...

Thanks for your blog. Great information; as I make progress I hope to make better use of it.

Carlson, in his book, recommends the use of copal for varnish / medium, but I understand that is hard to obtain now. Is damar similar in it's uses?

Also, what are your thoughts on wax based varnishes - would you consider it to be a matt finish??


Michael Chesley Johnson, Artist / Writer said...

You might also tell the purchaser that, in a year, they can bring back the painting to you for varnishing - and you can then charge them for this service. Just an idea, not that I've done it.

Carol said...

What type of brush do you use for the varnish?

Stanka Kordic said...

Gamvar makes a great varnish. They say you can apply when dry to the touch- when necessary- which I've always done with good results.

Bob Carter said...

I have used Utrecht's damar varnish kit, which takes the guess work out of the proportions. My advice to anyone who wants to try this is to be sure you have plenty of ventillation (ideally, outside), because you must use turpentine. (Odorless mineral spirits, as Stape has noted elsewhere, doesn't dissolve damar.) Turpentine has a narcotic effect and in the quantities needed to make up a batch of varnish can result in headaches or worse. (I have access to a fume hood, and follow standard chemical safety practice.) Also, be sure to use artist's grade turpentine, because house paint grade will discolor. I dilute the finished product with an equal volume of turpentine, so that it is not liable to be too thick in a single coat. I have applied the varnish with a throw-away bristle paint brush, which can be obtained cheaply in any paint or hardware store.

Philip Koch said...

Stanks Kordic explains Gamblin says its Gamvar varnish can be applied as soon as the paint is dry to the touch. (If true, that would be great). Was wondering where I can find more information about this. Didn't see anything on Gamblin's website.

My other question is about spray retouch varnish- is it just me or do other people feel it gives a pebbly instead of smooth surface? It looks more matte to me and more dull than when a varnish is put on with a brush. Is this just a necessary evil one must accept when one has to deliver a wet paintingl?

Stanka Kordic said...

Philip, here it is more accurately stated by Gamblin:

Hope that helps.

Edward said...

After reading the last two posts and all the comments I have to chime in on the subject of final coatings. There are many more qualified than myself on the subject, but this is what I know. All mediums and binders(linseed, poppy, walnut, etc.) are not suitable for use as a final coating. Many use a medium (including myself) to 'oil out', or to bring up flat spots and saturate colors where the binder has sunken in when continuing on a painting. When doing this please cut the medium down with a dilutant to decrease the amount of yellowing by making it leaner, and wipe off excess. All alkyd mediums including liquin, the galkyds, etc., are considered fat(mostly oil with a small amount of alkyd resin). When you applying medium to a painting you are adding a yellowing layer over a painting. Something you obviously want to minimize, especially towards the completion of a painting. We all want to keep the cools in our painting, cool, and keep our paintings looking like we intended them to when we painted them. Oil paintings yellow with age regardless, so you do not want to add to this effect by loading on excessive yellowing layers to your painting. Would you rub linseed oil over your work as a final varnish? To me, you are doing a similar thing running an alkyd medium over a painting as a final coating even if it doesn't yellow quite as much, or seem to initially. Oiling out is viewed as an accepted practice, but I think it should be kept to a minimum especially at the end. A better solution is a retouch varnish (see below).
As far as actual final varnish coatings, natural resins (damar, mastic, copal) become brittle, yellow, and discolor with age. Worse, they cross-link with the structure of the painting. They literally become part of a paintings' physical structure. Think of the paint layer as composed of molecular chain links, and when a powerful solvent hits the surface of a painting it opens it up (think of a link on a chain opening up to a U shape), then when the solvent evaporates the resin and paint layer close links, becoming a continuous structure. Where does varnish resin end and the painting begin? When removing these varnishes you are at a minimum chemically biting into the paint layer even if you do not take any paint off while doing so. One can only use strong toxic solvents to dissolve natural resins, and they require even stronger solvents to remove them over time as they age.

Edward said...

The other options are synthetic resin and acrylic varnishes.

The Ketone varnishes tend to yellow with age. The acrylic varnishes are a high molecular weight (large size--much greater in particle size as damar or gamvar) , and although they make a brilliant layer, the larger sized molecules sit on the surface and will never have the luster or beautiful look of a freshly applied natural resin varnish. They also tend to mix reflected white light with the more textured parts of a painting thus reducing the saturation of the colours. This evidently isn't a problem with flat parts of a paintings' surface. Also, when applied thick, acrylic varnish can look like you coated the painting with a layer of plastic. At least one of the older acyclic varnishes available is a decades old formulation, one of the first generation of these, and even with the claim of easy removal, it becomes more insoluble as it ages. A few years ago I removed one of these varnishes from a Birger Sandzen painting and had to use Acetone. You do not want a powerful solvent like this or any other applied to a painting if it can be avoided! Having said all that, the acrylic varnishes do look good, and in the end it comes down to personal preference taking into account all pros and cons discussed as well as aesthetic intention. Golden and WN makes some excellent ones.

Gamvar, a low molecular weight (very tiny particle size, like damar) hydrocarbon resin that is water clear and stays clear as it ages, and is easily removable with mild low-odor mineral spirit solvent. Its the only thing that looks like natural resin varnishes without all of their many drawbacks. It can also be applied within a couple weeks or sooner when the surface is dry to the touch and paint will not lift, although it can slightly slow the paintings' complete drying when doing so. Gamvar can also be used as a retouch varnish, cutting it 5 parts mineral spirits to one part resin. I brush on if the surface is dried or use a high quality mister to spray it on. PLEASE use a respirator, and not a paper mask and do it outside. Gamvar also has a UV stabilizer as does some of the other modern varnishes.The resin in Gamvar is also used in as a binder for Gamblins' Conservation Colors which are used in museums for in-painting because of easy removal, excellent pigment wetting, and the other properties discussed above.
I personally think this varnish (Gamvar) is the biggest breakthrough to benefit artists in recent history. It is really a miracle.

Edward said...

I should add I do not work for Gamblin or receive any compensation for emphatically recommending Gamvar to all.

Laropal A-81, the resin used in Gamvar, is also availible for purchase at Kremer pigments.

I have simplified greatly in my long-winded comments above, but hope to have conveyed the main ideas.

Edward said...

Phillip- My guess the difference between spraying and brushing retouch is the spray is more dilute and thus more matte, and when brushing on retouch the varnish tends to load on heavier creating more saturation.
The spray-on being more dilute, is probably going down thinner and more uneven/broken up causing the pebbly feel. Just a guess. Is this a problem you have experienced with all spray-ons?
As far as sending out a wet painting without a final coating see info concerning Gamvar and almost immediate use in the links to the pages I dug up below;

....this newsletter is fantastic as it covers the subject much better than I did above, as well as offering useful hints on how to apply a varnish for desired effects.
Everyone pay particular attention to the great technique of bringing up flatter, less saturated spots when varnishing a painting by applying more to those areas alone, and not covering the whole painting with another application to get an even varnish coating.
Also mentioned, when using Damar or other natural resin varnish it is recommended to use it fresh by making it oneself, like the Utrecht system Stapleton uses and recommends.

As for my personal approach when applying Gamvar, I prefer to cut the varnish by half which enables me to have saturated colors and protect the painting, without adding too much glare or reflection to the paintings' surface which I find annoying in a full strength application of a glossy varnish. This helps the painting to be seen from all viewing angles by minimizing the glare problem.

Stapleton Kearns said...

Copal is unavailable today and is brittle. I learned to paint with Taubes copal medium. Today products labeled copal are likely alkyd.
Their are wax varnishes and I think they are probably OK but I don't know a lot about them. I recommend dammar, as I am most familiar with it.

Stapleton Kearns said...

I have published a document as an example that does just that.

Stapleton Kearns said...

I use a big bristle or a cheapo brush from the hardware store. Brushes that shed are not good though. I spray varnish when a painting is new.

Stapleton Kearns said...

Others have spoken of that too, I will check it out.

Stapleton Kearns said...

Thats about what I do but I use a hooded sweatshirt.

Stapleton Kearns said...

Philip; I haven't noticed that problem. I will watch out for it though. My paint has a rougher surface so maybe it doesn't show.

Stapleton Kearns said...

Thank you for your contribution. You have brought excellent information to this forum.