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Fine Art/conserving a Renoir etching


Renoir Mold?
Renoir Mold?  
Hi, Dolly.

In 1987 I purchased the lithograph "Portrait of Louis Voltat/Valtat" by Renoir
a very reputable gallery. Although it was barely noticeable at the time, the
called my attention to a small spot on the paper outside the image area. To
best of my recollection, they said it was "mold" and they would "put it in a
with crystals" for a few days before shipping it to me. When I eventually
the etching the spot was gone.

Now, some 20 years later, the spot has returned. It's tea-colored, stable in
(about 1/2" across, irregular borders), but obviously I do not wish to see it
with such a striking piece of art. What is this spot, and how do I get it to go
without putting my Renoir at risk? How can I find a reliable conservator, and
should I expect to pay? The original sale gallery is no longer in business due
the death of the owner.

The attached photo shows a detail of the affected area, magnified; it doesn't
appear quite so objectionable in normal lighting. In looking at the enlarged
photo, it appears that there are pinpoint spots as well to the right of the big

I live in a humid Southern coastal city, but the lithograph has always been
kept in
an air-conditioned room, out of direct sunlight. It's on vellum.

Also, any conjecture on market value for this print? It's otherwise in good
condition. I did see one offered on eBay for $6500 last year by a gallery that
claimed it was selling at 40-75% off gallery retail.

Many thanks-I hope you can help me get my sick baby well! :)

Dear David,

The mark on your Renoir is often referred to as foxing, primarily due to a form of fungus (mold). Mold requires two things to grow: moisture and food. Fungi love cellulose, especially the easily digestable papers of fine prints.

When you purchased the print, the gallery put it in a closed container with thymol crystals. Thymol vapors removed the initial spot, but since thymol is volatile and vaporizes, it cannot provide permanent protection against mold. The fact that the mold has reappeared means it is getting some kind of moisture. It is considered best to keep the art in an environment below 70% relative humidity; with an average of 50-60% being even better. You should also refrain from hanging art on an outside wall that lends to condensation. An indication is a cold or damp exterior that often will have the existence of mold (greenish brown color) on the surface. Proper matting of the print with acid free material will keep the print from lying directly on the glass as this promotes condensation. Good circulation of air around the framed art reduces chances of mold growth. You can improve the circulation of air by attaching small pieces of cork, felt pads, or similar material to the lower two corners of the frame; thus keeping the frame away from the wall.  

To find a conservator in your area, Google “art conservation” and you will find many non-profit and for profit resources. I found retail examples that have a price range for your print of $5500-6500. It is well worth the effort and cost to conserve. Pricing varies, but your print is not in bad shape and should not cost too much.

I hope this information is helpful.

Best regards,

Fine Art

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Dolly D Headley


I can assist with identification, acquisition, sell representation, and care of fine art prints and original paintings. Some of my artist specialties include Henri Toulouse Lautrec, California Artists, and the Modern Masters. I can also assist with information on getting professional appraisals and authentication.


Dolly D. Headley, owner of Headley Fine Art, LLC, has provided consultative art services to retail gallery clients in Sausalito, CA, and at since 1998. With over 14 years experience as a Senior Art Consultant, Gallery Director, and an extensive art research library; Ms. Headley has provided hundreds of people with her high quality personalized consultation services and solid guarantee of satisfaction. Dolly is a volunteer at Crystal Bridges Museum of American Art.

Member of the Association of Online Appraisers.

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Bachelor of Science; Self taught with thousands of hours research and retail gallery consulting. Personalized mentorship from various experts in the industry.

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