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!

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.

Ps.
 

After writing my reply I found this link
http://en.wikipedia.org/wiki/Varnish

I think it might be helpful.

Time duration of finished work important in considering for varnishing
 

Hi,
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.

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.

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?

Thanks!

Jennifer:

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.

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.

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?

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.

Sorry, I meant "completely organic" like the egg white mixed with salt.

Some guys like Damar, I personally think that it yellows too fast, but other guys haven't experienced the same problem, I think that's due to climate differences, it is very humid here in Brazil.

Hope everything will be okay with your experience now.

I think we might start another thread about damaged paintings, but here's an example about the Mona Lisa.
Her portrait was painted from 1503 to 1506. Raphael loved the portrait, which was much different from the one we can see today, and he did a sketch in order to use the pose. In his sketch the woman has eyebrows.
He borrowed the pose to do Maddalena Doni's portrait.
Both women have eyebrows and you can see eyebrows in Da Vinci's work too. The point is that many of his paintings seem to have been damaged by restorers, not only eyebrows, but clothing details and skin color too.
So, as we can see, it was not a matter of fashion.

Claudemir, thank you for the information! I had no idea that you could make a varnish out of egg white and salt. I know that eggs are used in egg tempera but I have never personally tried it.

Did the masters of the Renaissance use a final varnish?

Yes they did. There is an entire section on varnishing in Cennino d'Andrea Cennini's book "Il Libro dell' Arte" published in the 1400s. Early varnishes were often done from amber or mastic or copal, and sometimes by mixing a solvent with a balsam such as Venice Turpentine. Damar/dammar varnish has come into primary use in the past 100 or so years.

Michael is right.

Egg varnish was widely used because it was a lot easier to prepare then the other ones. The removal of egg varnish is done with a moistured rice paper applied on the surface of the painting, and then it is removed and the surface is cleaned with cotton swabs.

Thank you, Michael! Do you think they intended for someone to remove the varnish to clean the painting or is that something that was developed later by conservators?

That sounds like it would be less stressful to the painting than solvents. How come eggs don't go rancid?

I still don't know what Michael is about to say, but they used the varnishes for the same reasons pointed out in this thread, protection, sunken areas, etc...

Because of the salt.
I tried it more than a decade ago and the painting still looks fine.

Thank you for answering my questions. Why is it best to avoid organic varnishes like the one made out of egg white and salt?

Because that is not a strong varnish, yellows faster than the others and can be really messy to apply. The good thing is that it is non toxic, but if you go outdoors you won't have problems using retouch varnish. The final varnish can be used in your studio (if you are using brushes).

A good example of the quality of current varnishes is the one used on Rembrandt's Night Watch. A crazy guy threw acid on the painting (and that was the second time the painting was attacked), immediately after that a security guard started removing the acid with destilated water and fortunately the acid didn't reach the painting, it only scratched the varnish surface (of course there were thick coats of varnish). The results woundn't be the same if that happened to egg varnish.

Ps.
 

Egg varnish "can" go rancid if not mixtured correctly.

Claudemir,

This is off topic again but thank you for sharing that info on the Mona Lisa. What you discussed with the Raphael images was really interesting. If you ever want to start a new thread on damaged paintings I would be happy to learn about it and I'm sure many others on this forum would as well.

Thanks!

Amanda

Fine, as soon as I find some time.
:)

While responses to this thread contain a lot of good information, there are also a number of errors, misconceptions and suggestions which are not entirely sound if taken as unqualified advice.

At the risk of starting a flame war, I presume to address them on the basis of 50 years experience painting in oils, and dealing with a wide variety of paint materials of all types:

One problem in discussing materials and methods is first to define the terms. Most people understand paint to be "dry" when it can no longer be manipulated, lifted from the surface, or malleable when handled. Claudemir is correct to state that the process of oxidation continues in oil paint films for a long time. However, for the purpose of addressing the question of a "final varnish" for a painting, it is only necessary for a paint film to reach a state where free volatiles have evaporated. As further noted, the length of time for a painting to reach this condition depends upon the thickness of the films and also ambient conditions.

The ultimate yellowing of oil films is a chemical reaction which has nothing to do with the oxidation of polymerized oils and/or resins. Curiously, the nature of linseed oil paint films is to yellow and darken when deprived of ambient sunlight. Humidity exacerbates the yellowing process, which is readily demonstrated by the oil itself, even before being incorporated into paint; it becomes increasingly lighter when exposed to sunlight.

A painting stored in a dark, damp place may yellow very noticeably in a relatively short time. Exposed to normal room (sun)light, the yellowing will reverse. The oil films cease to be reversibly reactive when the paint film has reached a certain point in the aging process . . . usually several decades.

Yellowing of the varnish films is a process independent of reactions taking place within the painting. Many old paintings have been restored to a state nearing their original condition when multiple layers of varnishes applied through the centuries (and the dirt, dust and smoke they contained) were removed by conservators. The most famous example was when Rembrandt's painting "The Night Watch" was restored. It had been referred to by that popular name for a great many years, when in fact, it is a daylight scene. (proper title, "The Company of Frans Banning Cocq and Willem Van Ruytenburch )

All solvents, vehicles, oils and resins generally associated with oil painting are "organic" in the sense of the definition of "organic chemistry".

Modern conservation methods find the old practice of applying numerous heavy coatings of varnishes of various compositions anathema to preservation.

While the wikipedia link provided is a good general-knowledge overview of materials which the term "varnish" comprises, it has little or no practical application to the especiality of oil painting or the preservation of oil paintings. For that matter, linseed oil alone is, by definition, a varnish in itself!

Marcus, the principle is correct, but you have it reversed. As paint films continue to dry and give up their volatiles, they shrink They do NOT "grow". Problems with cracking and crazing may be caused by violating the "fat over lean" principle when making the painting. If thin, faster drying (lean) layers are applied over heavier, slow-drying (fat) layers, the lean layer will shrink or embrittle over a soft layer which is not shrinking. Think of Bruce Banner watching the surface of a mud-hole crack in a net-pattern as it bakes in the sun!

Varnishing too soon may cause cracking, but a more likely result (for damar or mastic at least) will be that the varnish will become incorporated into the painting itself through the process of solvent transfer, negating the advisability of having a "final varnish" be a removable, protective layer.

While a painting 25 years old could very likely suffer a wiping with turps (or any other solvent) without visible damage, most conservators would cringe at the thought. Usually, the first line of cleaning is to dab the painting surface with surgical cotton dampened in distilled water. Of course, extreme cases would require something more, but in general, it's not a good idea to wipe down any painting with solvents prior to varnishing.

Adding wax to a "final varnish" is questionable on a number of levels. First would be the question whether the varnish chosen and wax are compatible. Damar and pure beeswax is a compatible mixture. The problem is the result is a varnish that is malleable, attracts dirt in its own right, and is much softer than damar alone.

In choosing a material to use as a final varnish, two requirements are inviolable: 1. The varnish should provide protection 2. The varnish should remain indefinitely soluble in its parent solvent to enable its ready removal at a future date.

A better long-range tactic would be to apply a suitable material as a final varnish, and regardless of its composition or final glossiness, a satin finish may be readily achieved by the application of a wax layer that is not part of the varnish

Here, Claudemir addresses a major problem we encounter in discussing materials and methods. The traditional materials of oil painting have always been open to the question of the nature of the source, and the quality of the material. Resins are especially problematic, as those commonly associated with oil painting (damar, copal, mastic); each is a generic term encompassing a wide range of similar species, each with quite different individual qualities and properties. Sometimes it depends where certain species are grown.

What works well for me in the dry, cool climate of the high desert US west may very well cause specific problems in the humidity of tropical Brazil ! This is why it is so necessary for painters to become intimately acquainted with their materials, and knowledgeable by running their own tests. It's fascinating how closely processes in the studio and the kitchen are related! About the relative quality of materials, I could never understand how anyone could dislike oysters . . . until I was served a "bad" one! Simlar considerations apply to the painting materials we prefer!

Our modern "just run down to the store" culture primes us to be surprised at such a suggestion as using egg-white for varnish. Anyone who has left the dirty dishes in the sink overnight quickly realizes that a number of food-stuffs are very tenacious adhesives and coatings . . . In earlier times, folks were intimately acquainted with where their lunch came from, and readily observed how blood, milk, eggs, and a number of other "food" items could provide substance for "paints" of different types and applications.

If you have ever encountered the "beauty secret" of using egg-whites in a facial treatment (to eliminate wrinkles?) you can readily understand how using egg-white "varnish" on a painting might not be the best choice . . . shrinkage is extreme, the film is brittle, and although Claudemir refers to being able to remove it easily with water, I wonder . . . after all, eggs (the yolk) are the major ingredient in "egg tempera" . . . a paint choice that's far more stable and permanent than oils! (ever had your car "egged" ??)

I was missing your comments here Richard. :)

I prefer to use a mix of gloss and mate varnish, what about you?


Ps. I have never had my car "egged".

I'm awfully old-fashioned. I use a 6:4 mixture of damar and mastic, I make up the varhishes in the studio using good turpentine and the best quality resins at a 5# cut (proportions: five pounds of resin to a gallon of turpentine)

This mixture is easier to manipulate than damar alone. I apply the varnish with a 2" badger sash brush and "lay off" the surface with the tip of the brush as the varnish tacks up to eliminate a high gloss.

I've heard a lot of good things lately about Gamvar, which is a synthetic varnish (I believe methylacrylate resin). The resin is dissolved in mineral spirits, and is reported to remain dependably water clear over time, as well as readily removable in MS indefinitely. It sounds good, but I haven't tried it yet myself . . . mostly because I don't see a pressing need to replace a method I've found suitable. Those who have tried it report that it doesn't lend itself to manipulation in application, so what you see is what you get!

I'm glad you haven't been "egged" ! (Maybe vandals in Brazil have better sense?)

Richard, thank you very much for your insight. You mentioned that artists can run their own tests on materials. How would I go about testing the materials I'm using? I am currently using walnut oil, walnut/alkyd oil, and liquin as medium (not all at once). I've heard some negative things about alkyds and liquin such as delamination and have not worked with them long enough to see those kinds of problems in my work. I'm in the process of researching varnish and can see the benefit of testing the material before committing to it. Does an artist need to try many different mediums and varnishes in order to become well acquainted with them?

Well, it is not common to have your car attacked by vandals here, in fact, it is very rare, but when it happens during some sort of manifestation, things go really bad.

Well Jennifer, I think Richard will answer your question soon, but meanwhile I'd like to tell you that mediums are something very personal. It depends on your way of working. Some mediums accelerate the drying of paints, others slow down. You should watch Daniel Greene's video "Erin", in this video he addresses this subject in detail.

If you don't have access to the video, we can discuss it here on in another thread.

You mentioned Walnut oil, that's wondeful but adds a lot to the drying time. In my Country people don't have the culture of patience to sit for long sessions, so I use my mix of 1 part of stand oil e 4 parts of odorless mineral spirits, this medium accelerates the drying time. I also use Titanium white of flake white, which get dry a lot faster than zinc white.

You will have to find your own recipe to your medium, but I also avoid the ones with bad reputation.

Jennifer, for an artist to test materials in the studio, one realizes first off that we don't presume to have a command of either organic chemistry, nor of laboratory grade procedures and equipment.

The first test is quite naturally, one of a simple "hands on" assessment. Does the material "do" what you want it to? Does it handle to your liking?

Tests for permanence are rather more subjective, as there may be a great number of variables which will be out of one's control as soon as a painting leaves your possession. I rely on a rather "dumb brute" method for testing my materials, simply subjecting test samples to outdoor weather. I place test samples of painting supports, paints, mediums, varnishes, etc. outdoors on the weather side of my studio, and leave 'em there. Between exposure to sunlight, temperature variations from -20F to over 100F, rain, snow, hail, sleet and frosts, a pretty good picture of a material's failure modes emerges. Naturally a painting would never be subject to that kind of abuse under normal conditions, but weather provides a semblance of accelerated aging. Naturally, it's not going to cover all the bases.

Learn as much as you can about materials from reading. To keep it very simple, my favorite book on that subject is Frederick Taubes' "Studio Secrets" alas, now out of print. Unlike a number of latter-day self-proclaimed experts on the subject, Taubes was a practising studio artist who based his methods on what is known of traditional "old master" technology, and as an entrepeneur who marketed painting materials and mediums was actively involved "hands on" in his business. He wrote the technical column in American Artist from 1942 until well into the 1950's, and taught materials and methods courses in seminars he gave around the country.

I think every artist who paints in oils should own a copy of Ralph Mayer's "The Artist's Handbook of Materials and Techniques". It contains a lot of sound, basic information, although it is overly ambitious in scope, and suffers from the fact that Mayer was more an "armchair" type who relied heavily on "hearsay" and recapitulating information from other sources as opposed to verifying the book's contents through his own working experience.

Beyond that, discussing materials and methods with your peers is almost always instructive (one way or another) but can be a minefield of errors and incomple information and bad practice. One should have a clear working knowledge of painting materials and procedures and a means for testing all the ideas which abound, rather than blindly following anyone's "prescriptions". It sounds forbiddingly complex, but hey, it's not rocket science, and the basics are very simple. All the complexities are either overlapping redundancies, or extrapolations which can fall back easily upon the knowledge of basic, sound painting practices for clarification.

Since I'm feeling reckless, (read stupid?) I think your questions about mediums would be better addressed in another thread, which I'll open in response to them. Claudemir wisely notes that the subject of painting mediums is one which is very personal with almost everyone who paints in oils, and has caused some dandy knock-down-drag-out flame wars on art fora as well as in person, when artists meet.

Originally Posted by Richard Bingham:
...Marcus, the principle is correct, but you have it reversed. As paint films continue to dry and give up their volatiles, they shrink They do NOT "grow"...

While I wouldn't refer to it as growing, from what I've read drying oils do expand, possibly as much as 15-25% as they absorb oxygen, and then will gradually lose volume as they release their volatile content over time. This can lead to cracking issues on a top layer surface which itself has already dried. The volatiles which may include acids and alkenes can also stay present in the paint film and react with some types of pigments, which may lead to discoloring with any top layers as well.

Richard, I found this out the hard way, but not consistently and not with Damar. I've used Gamvar with cold wax as the directions said. One came out beautiful. The other one was fine when I applied it, but later attracted all sorts of dust. It had darker tones, so maybe that was part of the problem - that the dust showed up worse?

I have one painting I will have to varnish in late March or so. It's got a lot of dark tones to it, and I am guilty of having used too much retouch varnish (Winsor-Newton). I'm concerned that Gamvar over retouch may not spread evenly - had this problem once before in a similar situation. Do you have any recommendations?

Try this experiment. Put just enough linseed oil in a palette cup to cover the bottom of the cup, and "pull up" visibly on the sides (that would be about 1/16" "deep"). Leave it in a warm, well-ventilated place (plenty of oxygen). At what point do you note expansion of the volume of oil by as much as 10%? What is the nature of the surface of the dry oil film as soon as the puddle of oil "skins over" ? Is it bloated, like a little bubble because of the volume of oxygen being absorbed, or does it resemble a raisin, shrinking in the sun from the loss of its liquid components through evaporation?

When linseed oil is heated to approx 475F in a vacuum in making stand oil, there is a slight noticeable increase in volume, as the purpose is to partially polymerize the oil, which requires the addition of oxygen, but that's not a dry film state.

Richard, I couldn't find Frederick Taubes' "Studio Secrets" at my library but they did have a couple other of his books, both on oil painting, and I put them on hold along with Ralph Mayer's book.

Jennifer, try Abe Books online for books out of print. I was able to "score" a couple of copies of "Studio Secrets" for my students very reasonably a few months ago!

At the risk of an omelet on my Buick ... You are actually both right. In the beginning, the drying paint film gains weight as oxidation means absorption of oxygen molecules, then as the chemical reactions release gases, the paint looses mass.

I am not a chemist but that is the way I learned it.

Ah! "The Rest of the Story". True enough. Oxygen is absorbed, resulting in the polymerization of paint vehicles. Though Mr. Beck offers the disclaimer, I'm confident we may rely on the fact he presents, i.e., absorption of oxygen results in a measurable gain in weight in a drying layer of paint.

The question, however, was not whether the paint gains weight as it takes on oxygen in drying, but whether it gains volume enough through the absorbption of oxygen to cause cracks to appear in a paint film. His subsequent observation, that the paint loses mass with continued "drying" seems to preclude that a surface "skin" of dry paint would be brittle enough to crack at such point as the wet paint is readily absorbing ambient oxygen, if that corresponds to an increase in physical volume.

I am not a chemist either, but I know what I have repeatedly observed in coatings of paint, and so gently refer you to the experiment I offered in a previous post.

Realizing some may find this nit-picking over detail a bit onerous (frankly, I'm annoyed at myself for pursuing it) I appeal to readers who do have a background in paint chemistry for their input.

Mr. Beck, your Buick is safe from me. You are a helluva fine painter!

Do you sell your paintings with the retouch varnish on them? If so, then what do you communicate to your clients about the need for a final varnish in the coming months?

As an Artist I find this subject to be most elusive :) it seems so anyway .... there are tutorials and or articles on every step of the life of a painting from start to finish. But what happens when its finished ..... I mean if its a portrait painting ... your client is going to want delivery of the painting sooner than later not leaving time for a final varnish .... so how do you all deal with that?

Mark

Hello there,

If I won't be able to apply the final varnish. I wait as much as I can to apply that before shipping the painting, something like 2 months. I have not had a bad experience so far.
Otherwise, I tell the client where he will find a professional who can apply the final touch.

Thank you ... I have to say you are the first Artist that shared more than just generalities .... this helps and its much appreciated :)