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-   -   Final varnish (http://portraitartistforum.com/showthread.php?t=8894)

Jennifer Bogartz 11-19-2008 10:04 PM

Final varnish
Is it absolutely necessary to varnish a painting once it is finished? What happens to an oil painting if it isn't varnished? I have some oil paintings on canvas that are several years old and have never been varnished. Do I need to clean the paintings before I varnish them? I live in Portland, Oregon where it is very humid, will this effect a final varnish layer? Thank you for any information you may have!

Claudemir Bonfim 11-19-2008 11:39 PM

Well, I noticed no one has answered your question yet, so I decided to give my two cents.

There are several reasons to varnish a painting, I specially like the effect, but the main reason is the protection. Dust, or any other undesirable thing, will stick directly to the paint if you don't varnish it. It will also be a lot easier to clean a varnished painting than an unvarnished one.

Some artists don't know, but oil paint never dries, it solidifies with the addition of oxygen molecules, and that's why the paint yellows with time. If the painting is varnished, then this process slows down a lot because the varnish yellows first (the Oxygen molecules cannot reach the paint easily) and can be supplied by new coats of varnish.
That's a tough job too, Mona Lisa lost the eyebrows during a process of old varnish removal.

Avoid organic varnishes!

Precious Paintings in museums receive very thick coats of varnish.

And yes, you have to carefully clean your painting before varnishing it.

Hope it helps.

All the best.

Claudemir Bonfim 11-19-2008 11:46 PM

After writing my reply I found this link

I think it might be helpful.

Marcus Lim 11-20-2008 01:48 AM

Time duration of finished work important in considering for varnishing
I'd like to add that timing is also an important factor to varnishing a painting. It's a definite no-no if you put a final varnish when the painting is touch-try, or recently done. This is because while we think the painting is dry on the outside, the actual fact is the painting is still 'growing' inside the painting. Putting a final varnish too early, results in serious cracking problems for the painting - think Bruce Banner ripping his clothes off if when turning into a hulk...

So often it's recommended to varnish only at least 6 months' after the painting's done - more than 6 months for thicker, impasto-ed paintings.

Claudemir Bonfim 11-20-2008 09:49 AM

Marcus is right. Now I use a retouch varnish when my paintings are finished. The final varnish is applied only after 6 months or later.

Amanda Grosjean 11-20-2008 09:54 AM

I never knew the Mona Lisa originally had eyebrow! I had always been told it was the fashion of the times. Interesting! It makes you wonder what other paintings have been damaged by cleaning over time.

I am a big fan of using temporary varnishes pending the final varnish. In between these two (like you said, minimum of 6 months) there is always a slight collection of dust on the surface. I always struggle to remove it since my paintings are full of ridges and raised areas. Wiping it with a cloth seems to just deposit tiny fibers (from the cloth) to the surface. Does anyone have a method that works for them? For example, a certain type of cloth, lint roller, vacuum?


Michael Georges 11-20-2008 10:43 AM


in addition to what has been said...I add that yes, it is a good idea to varnish your paintings. It evens out the gloss, relieves any sunken in areas, protects the paint layers from dirt.

In the past, I have varnished paintings that were more than 25 years old. I first used a linen cloth with a good turpentine to wipe the whole painting down and remove any dirt/dust. Let that completely dry, then used a drafting brush to remove any residual dust.

Gamblin makes a very good synthetic final varnish called Gamvar that I have had good results with. Studio Products also makes one that is more traditional. Have not used it, but they make first class stuff so I cannot imagine that it would be bad.

I try to do my varnishing in a draft free room with a space heater going so the room is warm. Put painting and varnish in the room and let everything come to room temp for a few minutes.

I add a bit of wax medium to my varnish as I like more of a satin finish to my paintings.

David Clemons 11-20-2008 10:45 AM

The six month guideline is only a general rule for a final varnish. It all depends on how the paint was applied and the sort of medium used, especially if alkyds were involved. A retouch varnish could be safely used in the meantime.

There's a brand of lint-free synthetic rags made by Scott that you can usually find in hardware stores that works well, or any other microfiber rag. I typically start with a dry synthetic bush, followed with a rag with just a tiny amount of spirits rubbed into it.

Jennifer Bogartz 11-20-2008 01:54 PM

Thank you for all your responses! Now I'm encouraged to try to varnish a painting. Will Gamsol be okay to clean my oil paintings with?

Claudemir, when you say avoid organic varnishes are you referring to Damar varnish?

Lastly, if acrylic paint can't be used over oil paint, how come acrylic varnish is acceptable?

Michael Georges 11-20-2008 02:33 PM

Gamsol will work just fine for cleaning those paintings.

You will find differing schools of thought about traditional varnishes such as damar and mastic. I personally find them completely acceptable, others will not. That said, I use a synthetic varnish on all my commissioned works as I have gotten the look just right.

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