Paintings on paper bags

[msails]

I have an artist who has done pastels on paper bags. I'm worried about the acidity in the paper itself. Is there something we can treat it with? Will it evetually destroy itself? Any help would be appreciated.
Also whats the best way to clean dusty oil paintings?

 

[Susan May]

It is not going to last long. But, you can help it live a decent life. UV glass, and a spacer between the mat and the art will help it. Also ask the customer to hang it in a dark(ish) room. (No big windows)

Some people might reccomend an acid reducing spray... um... I would talk to a conservator about altering the paper in any way. Also the artwork is pastel, it will be damaged by any spray that you offer to spray on it. (DON'T DO IT!)

Best thing is to prevent further harm, and inform the customer about proper materials for their next pastel project.

Good Luck.

 

[Dave]

So, this artist goes to his neighborhood purveyer of fine artist materials and drops about $ 3.00 a stick for pastels and takes them out of the bag and uses it for his support?




As far as the "dusty oil paintings" ...it depends. If it's truly just dust and the adhesion of the paint to the canvas and the canvas itself is in good shape then I'd just dust it with a horsehair brush and then take a clean soft cloth with a little turpentine and wipe the surface lightly.

If the "dusty oil painting" is not just dusty, but grimy then you should take it to a conservator or someone who is quite familiar with cleaning a painting. There are many different solvents that conservators use and it shouldn't be attempted by a novice except on your own Renoir hanging in your parlor.

The actual cleaning of an oil painting entails careful removal of the varnish hopefully applied after the painting has dried 6-12 months (or longer) and presuming no other conservation work needs to be done, several light coats of a removable final picture varnish. Sometimes a restorative, like salamander, is applied to a freshly cleaned painting, but the school of though seems to have changed about using salamander.

Of course the preferred treatment for an oil is to properly clean it and frame it using preservation techniques and a UV protectant coated glazing. When done thusly a picture varnish isn't necessary.

Years ago damar picture varnish was the preferred varnish but for the past 30 years or so new non-yellowing synthetic varnishes tend to be preferred. Damar varnish yellows and is "gummy" and a little more difficult to remove than the newer synthetic final picture varnishes.

Retouch varnish is not intended as a final picture varnish and shouldn't be used for such.

A problem arises when a painting has never been varnished such that the pollutants are not residing within and on the surface of the varnish but have actually penetrated into the oil paint surface. A conservator can help in such a situation, but it is laborious and expensive and can improve but never fully restore a painting.

 

[Rebecca]

Re the paper bag pastel support, using ArtCare for backboard and windowmat is a nice, safe, non-invasive way to neutralize any acids etc that are generated by the breakdown of the bag. Matting should probably be changed every 15 yrs or so.

Rebecca

 

[wpfay]

Of course the preferred treatment for an oil is to properly clean it and frame it using preservation techniques and a UV protectant coated glazing. When done thusly a picture varnish isn't necessary.

I understand the advantages of glazing oil paintings, but I didn't realize that varnishing was no longer necessary when glazing is used.
I thought that one of the purposes of the varnish was to retard the desiccation of the pigment vehicle (linseed oil). Assuming that is the case, wouldn't varnishing still be applicable regardless of glazing?


The paper bag thing....Lautrec & Degas both worked on butcher paper when they couldn't afford canvas. Some of those are still around.

 

[Puppyraiser]

Here is the chance to trot out a very knowledgeable sounding phrase... "inherent vice" It means that the item itself will fail and no framer in the world can make it otherwise.

 

[Dave]

Of course the preferred treatment for an oil is to properly clean it and frame it using preservation techniques and a UV protectant coated glazing. When done thusly a picture varnish isn't necessary.

I understand the advantages of glazing oil paintings, but I didn't realize that varnishing was no longer necessary when glazing is used.
I thought that one of the purposes of the varnish was to retard the desiccation of the pigment vehicle (linseed oil). Assuming that is the case, wouldn't varnishing still be applicable regardless of glazing?...

I've always varnished oil and acrylic paintings whether using glazing or not because the colors lose their brilliance over time and darken and a varnish, especially a gloss varnish, makes the colors more vibrant. Also, even though glazed the extra protection a varnish affords I find desirable.

Different oil colors also dry with a different sheen. If you hold up an unvarnished painting and look at it from an angle you can easily see this. Varnishing will give a good uniform overall sheen to a painting.

You may very well be right that the varnish stabilizes the painting, Wally. I probably spoke too soon and didn't consider this possible advantage. Hopefully Hugh will chime in and shed some light.

 

[Jim Miller]

...I thought that one of the purposes of the varnish was to retard the desiccation of the pigment vehicle (linseed oil). Assuming that is the case, wouldn't varnishing still be applicable regardless of glazing?...

That's a good question, Wally. Varnishing a painting does no harm, and imparts visual finishing effects as noted by Dave. So, preservation is not the only reason to varnish. It makes sense that a layer of varnish would retard the drying-out of the linseed oil in the paint. I hope someone knowledgeable, such as Hugh or Rebecca, will respond with more information on that aspect.

Conservators say one advantage of glazing a painting is that it slows down the drying process of the paint, which results in better adhesion and a more durable painting for the long term. Probably varnish and glazing together would work best in retarding excess desiccation. But if it came down to a choice, it seems to me that closing the frame package with glazing and solid backing would serve that purpose better than a layer of varnish.

 

[Verdaccio]

Oil paint doesn't really "dry", it "cures" by oxidation. The vehicle, most often linseed oil is combined with a binder - pigment - and these days most paint includes fillers, extenders, and stabilizers such as alumina hydrate.

The thing that protects an oil painting most over time is the pigment. Most pigments are derived from minerals, are very light fast, and extremely stable over time. Thus, it is important to use very good paint with an appropriate pigment to oil ratio, and minimize fillers which can make your paint layers underbound.

All that said however, I always varnish my paintings. Oil paint is pretty durable, but you want something between your paint and the atmosphere - not to mention the benefits of light refraction mentioned above.

An oil painting, put together in a reasonable manner, and displayed in an average house of today can easily have a life expectancy of hundreds of years. Glazing is simply not necessary unless there is a need to protect the work from some other form of hazard.

Further, in my opinion, glazing interferes with the basic viewing quality of oils. Oil paintings have wall presence. That presence is a sense of depth, luminosity, and saturation of color given by the penetration of light through the layers of paint and reflecting back to your eye. I find that even museum glass interferes with that interaction and the painting looses a quality of that wall presence.

 

[Jim Miller]

The double standard again.

...Glazing is simply not necessary unless there is a need to protect the work from some other form of hazard.

Following that logic, why glaze any artwork? What "other form of hazard" would you consider to be a reason to glaze an oil painting? It seems most hazards could affect an oil painting on canvas as well as, say, a watercolor on paper. Sure, there are differences. Oil on canvas may be better able to resist most hazards than most other kinds of artwork -- scratch resistance, puncture resistance, or fade resistance, for example.

But nearly all artworks are displayed in climate controlled conditions and given reasonable care by their owners. Perhaps the most common hazard is soiling over time, from airborne contaminants. Glazing provides almost perfect protection from that most-common hazard, which affects all exposed surfaces. While it is true that a properly-varnished oil painting may be cleaned and revarnished, that is an invasive process and, according to conservators, generally contributes to degradation of the paint layers. Other artworks may be cleaned by conservators as well, but that work is seldom required because of glazing.

Repairability might favor a canvas painting, too. For example, a damaged oil paint layer or its canvas support may be repaired more easily than a watercolor image or its paper support. But in any case, the hazard of mechanical damage is unpredictable and always exists.

In terms of protection from hazards, saying an oil painting doesn't need glazing as much as another art medium does is like saying an adult doesn't need a seat belt as much as a child does. No matter who is wearing them, seat belts provide protection from hazards. No matter what the artwork, glazing provides protection from hazards.

...Further, in my opinion, glazing interferes with the basic viewing quality of oils. Oil paintings have wall presence. That presence is a sense of depth, luminosity, and saturation of color given by the penetration of light through the layers of paint and reflecting back to your eye. I find that even museum glass interferes with that interaction and the painting looses a quality of that wall presence.

Can you think of an art medium to which those sentiments would not apply? Consider the sublte textures of a pastel painting. Given the fact that glazing affects the visual properties of all artworks, why should we bother to glaze any art?

 

[Dave]

I weigh in the middle between Verdaccio and Jim on this one. It is imperative for the preservation of any work on paper to have glazing for preservation, but it isn't as necessary for an acrylic or oil on canvas as long as they are properly varnished.

I agree that the glazing, even museum glass, tends to take away some of the subtleties of texture and does block some of the visible light spectrum on any work of art. Every canvas in my home is framed without glazing for this reason and I have very few customers who choose to glaze works of art on canvas.

It could be argued also that acrylic should be used on any painting if glazing is used at all since the chance of physical damage from broken glass to a painting is always present.

For most environments personal choice would dictate whether or not to use glazing. If I personally had a very valuable and collectible work I'd probably choose to use glazing ...Optium Acrylic being the first choice.