Why do we mount photographs behind glass?

[scott_6029]

So, how much longer will a print last behind glass? VS. No glass? I am talking about pollutants. I priced museum glass and it was quite expensive.

Now, for some of my 'collectable' expensive photo's where I am concerned about damage (fingerprints, somthing getting on the print, etc.) I put those behind glass. But my images.....where I can make another one....

Boy, I see both sides of this one.....I guess you pop for the expensive glass to get closest to the 'best of both' worlds when you need to?

[roteague]

So "behind glass" equates to quality. Actually for me, not behind glass is a better way to experience a print. When I am evaluating one of my prints, I don't get out a piece of glass and put it behind it, that would be silly. So why should I display them that way? I think behind glass is just what we are used to.

That sounds fine. We all have our own sense of what constitutes "quality."

[Sal Santamaura]

It's important to understand that the UV-absorbing Museum versions of Tru Vue achieve their selective transmittance by adding a laminated plastic layer which, in my opinion, significantly degrades images. I use only the laminate-free "plain" AR.

In my opinion, for black and white fiber-based (FB) or chromogenic color prints that will be displayed indoors, there's no need to be concerned about UV. Commercially manufactured chromogenic papers already include UV filtering; black and white FB should not be affected by normal gallery levels of UV, even from halogen lighting, after that illumination passes through glazing. Of course, if direct sunlight hits the prints, UV is the least of one's problems.

[roteague]

It's important to understand that the UV-absorbing Museum versions of Tru Vue achieve their selective transmittance by adding a laminated plastic layer which, in my opinion, significantly degrades images. I use only the laminate-free "plain" AR.

Polarizing filters and the windshield in your automobile does this as well.

[naturephoto1]

It's important to understand that the UV-absorbing Museum versions of Tru Vue achieve their selective transmittance by adding a laminated plastic layer which, in my opinion, significantly degrades images. I use only the laminate-free "plain" AR.

In my opinion, for black and white fiber-based (FB) or chromogenic color prints that will be displayed indoors, there's no need to be concerned about UV. Commercially manufactured chromogenic papers already include UV filtering; black and white FB should not be affected by normal gallery levels of UV, even from halogen lighting, after that illumination passes through glazing. Of course, if direct sunlight hits the prints, UV is the least of one's problems.

Hi Sal,

Tru Vue does not use any lamination for Museum Glass according to their spec sheets. They claim that it is the only non-laminated conservation quality antireflective glass on the market. The glass is made using thin film coatings deposited onto the glass. A microscopic layer of silica based UV-blocking Agents (particularly for the 300-380nm range) is cured onto the surface of the glass. Tru Vue used to indicate that the coating blocks a minimum of 97%, they now say 98%. Both Museum Glass and the AR glass both have the Magnetron sputter coating for the Anti-reflective coating. AR Glass limits only 78% of UV.

See these links:

http://www.viratec.com/downloads/museum_glass22.pdf
http://www.ilovemuseumglass.com/aboutmuseumglass.asp
http://www.viratec.com/downloads/ultra_clear31.pdf

Additionally, there is concern for UV given off by fluorescent tubes in many places that may adversely affect photographs and other art work.

Rich

[Helen Bach]

Schott Amiran TN has the UV absorption layer in a lamination - it's also a 'water-white' glass with an anti-reflective dip coating. It may have a different name outside the USA - there is a large range of Amiran glass available. The lamination didn't seem to affect the image quality for the sample I saw. It's one of the most expensive glazing options. Being laminated does give it a degree of safety in the event of a break. Laumont here in NY offer it as a glazing option.

[Sal Santamaura]

...Tru Vue does not use any lamination for Museum Glass according to their spec sheets. They claim that it is the only non-laminated conservation quality antireflective glass on the market....Tru Vue used to indicate that the coating blocks a minimum of 97%, they now say 98%...

That's interesting. Perhaps the samples my local framing shop has are not current, since what was apparently Tru Vue's former laminate is textured and visible without straining. Maybe the change of percentage happened when this new approach was implemented.

...Additionally, there is concern for UV given off by fluorescent tubes in many places that may adversely affect photographs and other art work...

I remain convinced that chromogenic color prints and black and white FB prints behind "plain" glass are essentially immune from adverse UV effects when displayed in ambient fluorescent illumination. Other works, e.g. watercolors, are a different matter entirely. I have not researched inkjet prints, but would refer to Wilhelm for reliable data on them, at least as far as UV-susceptibility is concerned.

Schott Amiran TN has the UV absorption layer in a lamination - it's also a 'water-white' glass with an anti-reflective dip coating...

Denglas used dip coating and always exhibited significant defects resulting in long searches for a suitable area to cut. Tru Vue AR's sputter coating seems to be much more uniform. Also, Tru Vue is 2.5mm thick as compared to Denglas' 2.0mm, a significant advantage in larger frames. I don't remember how thick the Schott Amiran TN is.

...It's one of the most expensive glazing options...

Indeed. When checking several years ago I couldn't find anyplace in my region of the US where it was available to look at. The high price probably ought to be expected though, considering this is a heavy product shipped from Europe.

[naturephoto1]

Hi Sal,

I believe that I have been using the current product. I think there is a bit of "texture" to the outer coating- that is the silica coating. Perhaps you can notice a difference in clarity between the Museum Glass and the AR, but from what I have seen, when lit, I see no texture or loss of sharpness. I would have to make a comparison, but this is the closest that I have ever seen a glazed image look like one that is "naked". The clarity, color, sharpness and contrast is astounding for my Chromira output Fuji Crystal Archive Glossy paper (up to 30" X 37.5") shot on Velvia 50 and Provia 100 shot with my Linhof Technikardan 45S.

Rich

[alec4444]

This is a great thread. I too have been battling this question, though sadly not because of gallery exhibitions...rather in my hallway. The point of contention in my head has been this: If I put my prints behind glass (which they are) why am I bothering with expensive papers? Granted, it may give the restorer extra satisfaction to see it during the cleaning a hundred years from now, but otherwise that lovely coated emulsion I paid so dearly for is really quite hidden behind cheap or fancy glass, pending your preference.

So for those of you glazing your prints...can you tell the difference in papers when they're behind glass? Or perhaps to be more fair, can anyone else distinguish the difference in your papers behind glass?

--A

[naturephoto1]

Alec,

The Acid Free Boards will not only last longer but the beveled cuts (acid board beveled cuts will yellow) should stay white for hundreds of years. Depending upon the photo paper you are using you should select Buffered or Non-Buffered Boards. The difference in cost between the "cheap" boards with acids versus Acid Free is small enough to not be a question in mind for anything that you want to last. I have friends that are custom framers or run frame shops/galleries. They have seen too often artwork including Dali, Shegal, Picasso limited edition prints prepared with cheap acid boards that were burned by the acids.

Rich