Skip to Main Content
Sign In
Toggle Navigation

Open the Navigation Management window, which can be used to view the full current branch of the menu tree, and edit it.

  • Instagram
  • Facebook

MITRA Forum Question Details

Image Picker for Section 0


  • Strange spotting/fogging on oil painting on aluminum ApproveRejectUn-ApproveSubscribeUn-Unsubscribe
    Question asked 2017-06-14 13:40:09 ... Most recent comment 2017-06-14 23:20:40
    Oil Paint

    ​I used an aluminum panel for a painting support for an oil painting for the first time. A month after the painting dried to the touch, I wrapped it unvarnished  in acid-free tissue, wrapped in foam, then in bubble wrap in a cardboard box on a flight. It was wrapped this way for about 1 week. When I hung it for my exhibition I noticed strange splotches that resemble mold. They are not uniform and were not there before packing. The aluminum was purchased at an art store with plastic vacuum sealed to both sides. I took off the plastic and primed it with 4-6 layers of Grumbacher Gesso for oils, sanding between each layer. I used Rublev Raw French Umber thinned with Rublesol for the underpainting, followed by Rublev paint straight from the tube with no medium added. The main colors I used were Lamp Black and Lead white. Is there some reason you can imagine that would cause this type of reaction? Will it go away when I varnish? I've read that using denatured alcohol and lead primer would help prevent this in the future (whatever this is), but wouldn't so many layers of gesso be good enough? Thank you!

Answers and Comments

  • EditDeleteModerator Answer

    I'm wondering if the discoloration was the result of a reaction between the white pigment and something in the packing materials. ​What sort of "foam" was used to wrap the artwork?

    Regarding the preparation of an aluminum panel for acrylic dispersion painting ground, I recall Gottsegen recommended finely graining the support with steel wool followed with a thorough cleaning with denatured alcohol, to ensure optimal adhesion. I don't remember any issue with discoloration from aluminum panel, however.

    Matthew Kinsey, Utrecht Art Supplies
    2017-06-14 14:20:04
  • EditDeleteModerator Answer

    ​Is there any way for you to post a picture of the problem?

    Kristin deGhetaldi
    2017-06-14 15:12:32
  • ApproveRejectUn-ApproveUser Comment

    ​I just tried to upload a photo. Not sure if it made it. BTW, the foam was over the tissue and was the thin, white foam. I recycled it from a photo printer who used it to wrap a photo printed on aluminum. 

    2017-06-14 16:49:55
  • ApproveRejectUn-ApproveUser Comment

    Foggy,spotted areas on oil painting on aluminum.JPG

    2017-06-14 16:51:42
  • ApproveRejectUn-ApproveUser Comment


    2017-06-14 16:56:54
  • EditDeleteModerator Answer

    ​So to begin we do not think this has anything to do with the aluminum support or the materials/techniques you are using. It is indeed strange looking and still a bit impossible to diagnosis without examining the surface in person so we will do our best to try and give you some advice here...
    1) It could be fatty acid effluorescence but I am leaning towards not. The primary reason being that I have never seen FA effluorescence that appears in such distinct circular patterns. To deal with this problem one can use a soft brush and/or a bit of OMS to wipe the stuff away and certainly varnishing will help if that does not fix the problem.
    2) This might be some sort of additive from one of the packaging materials that got deposited on the painting (thinking along the lines of PVC or something?). It is harder to advise on how to deal with this as it will entirely depend on the additive. Have you tried taking OMS to the surface? What does it do? Varnishing may or may not help but you also might risk locking in whatever additive you are dealing with....which again may or may not be a big deal.
    3) This could be mold....hard to tell. You can look up instructions on how best to deal with mold on paintings in our Resources section (there is a mold abatement document). Even if it is not mold it cannot hurt to treat the surface as if it were affected by a mold outbreak. After that then yes I probably would seal the surface with varnish. 
    I am sorry we cannot offer a more definitive answer...please let us know if you find out anything.

    Kristin deGhetaldi
    2017-06-14 23:20:40
  • ApproveRejectUn-ApproveUser Comment

    ​Thank you for the info. When the piece comes down from exhibition I'll test the OMS out and post the results. All of these suggestions you offered sound very reasonable. Worst case scenario, I'll sand and re paint the area. Luckily it's a fairly simple painting. Thanks again for your help. 

    2017-06-15 04:01:04

Page Settings and MetaData:
(Not Shown on the Page)
Page Settings
MetaData for Search Engine Optimization
MITRA Forum Question Details
This page cannot be accessed until you accept the Terms of Use, which can be found here.
Please note that this Terms of Use system uses cookies. If you have cookies disabled you will not be able to accept the agreement. If you delete our cookies you will need to re-accept the Terms of Use.
  • The Department of Art Conservation
  • 303 Old College
  • University of Delaware
  • Newark, DE 19716, USA
  • Phone: 302-831-3489