cons. reg. under old glass


MGF, Master Grumble Framer
Feb 15, 2005
Western Wisconsin
I was talking to a potentiol customer at a soccer game last night that he has an old print that has been in his family for years. His mother cherished this and when she died, he got it. He said that it is in a beautiful old frame with glass, no matting, and is yellowing. It is backed with wood on the back of the frame. He wants to preserve it as best as possible and I wuggested that he bring it in and we take it apart. I mentioned that it was probably against some sort of old cardboard, or even the wood itself which may have been a part of the yellowing, but the paper itself is probably just yellowing with acid-free back then. But we both agree that the old glass needs to stay so I thought that if the frame can handle it with both strength and depth, that we use use cons/reg against the print with spacers to keep it away from the image, and the old glass on top with spacers, so as to keep the old glass look. Have any of you done this? It sounded like a great idea to me...hoping again that the frame can handle it. I should probably mention that it is just the image in the frame, no matting or anything...I think spacers would be the way to go.
I can almost guarantee that there is no room in the frame for more than is in it. It won't hurt to 'bump out' the back. We have done the double glass thing and it looks OK. Or I make the customer swear that he will hang it in the upstairs hall, away from light of any kind. All else in the pkg is conservation...
Unless you use museum glass (anti reflective) the double reflection (now four reflective surfaces) cuts the contrast of the image somewhat making dark areas muddy and leaves colors weak. I have an original watercolor I estimate is no newer than the 1930's. The matting and backing has been updated with archival materials to reduce the destruction of the already yellowed paper. The frame and wavy glass are original. It is displayed under reduced illumination.

Don't believe that UV blocking glazing is a panacea. It is a step in the right direction. Visible light must be reduced as well or the damage will continue. Heat, humidity and pollutants are other outside factors that must be controlled to reduce the degradation of the art.
I have always really loved the look of old wavy green glass on really old items (photos, watercolors, etc). Does anyone know what the UV filtering numbers are for such glass? I mean, one, it is really dark green and two, it is probably twice as thick as the regular glass we now use. So wouldn't it be filtering out at least a bit more of the UV wavelength than current regular glass?

Just wondering...
Thanks to you all...will see what I have to deal oith when he brings it in.
Framar, I don't know for sure, but I doubt it is much better than standard glass - not enough to make a difference in protecting the art from UV.

The composition of soda-lime glass has changed very little. The methods for producing flat glass from it has changed many times over the past two centuries.