UV rays, glass, and pompous physics majors

Judge Roy Bean

Grumbler in Training
Mar 11, 2006
Seekonk, MA
I had a customer come in today right before closing. He wanted his Dartmouth diploma framed. We got to talking about glass. I told him about UV protection glass and he started laughing to himself. I stopped and he goes "Heh heh, all glass blocks uv rays." I said "really? You think so?" and he says "well ya I was a physics major."

well, I checked it out and yes glass does block UV B rays. But it does not block UV A rays. Both are bad for your skin and art. Its basically divided up by the wavelength of the ray. man i wish I knew that before this guy walked in. What if I was with a great long time customer who I allways sell UV glass to.....
So, when he comes back in to pick up his work, you can hand him a printout of the technical information and explain to him how you both were right.
And... now you will have a copy of it at your desk, won't you??
It is so interesting when you start to research UV light . . .
A basic overview of what I've found is below, copy / pasted from my notes.
Wilkipedia has a lot of good (understandable) info.

We are just finalising a UV block coating for our convex glass, release due within a week (or four !).
Samples and testing have been very positive.

Vacuun UV 40nm - 190nm / Far UV 190nm - 290nm / UVC 220nm - 290nm / UVB 290nm - 320nm / UVA 320nm - 400nm / Visible 400nm - 750nm / Infrared over 750nm


* Can pass through window glass.
*** THE ONE TO STOP ! Glass in the 280nm to 380nm blocking range.
* Is not affected by a change in altitude or weather.
* Is present all day and every day of the year.
* Penetrates deep into skin layers.
* Is 5% of the sun's rays.
* Is 20 times more abundant than UVB rays.
* Affects long-term skin damage.

*** 99% of the ultraviolet radiation that reaches the Earth's surface is UVA, ~ 315nm - 380nm. ***


* Cannot pass through window glass.
* Causes sunburn.
* Causes tanning.
* Helps the body with normal vitamin D production.
* Varies with the season. It is more intense in the summer than in the winter.
* Varies with weather conditions.
* Is more intense at midday than in the morning or late afternoon.
* Is more intense at high altitudes and near the equator.
* Is 0.5% of the sun's rays.
* Is protected against by the sun protection factor (SPF) in sunscreens.
* Is related to more than 90% of nonmelanoma skin cancer.
* Is related to cataracts.

High intensities of UVB light are hazardous to the eyes, and exposure can cause welder's flash and may lead to cataract formation.


How damaging is UVC ????????????? (Suspect not very abundant ?)
Used for sterilisation . . . what type of reaction of artwork to UVA ? V V V

The shorter UVC rays are excluded by the earth's atmosphere, although depletion in ozone layer is allowing some UVC light to penetrate at the Arctic and Antarctic circles.

UVC light is very damaging for the eyes cornea, but cannot penetrate the stratum corneum, the layer of dead skin cells that makes up the outermost layer of the skin.
It has little effect on normal skin tissue.
So, he's a physics major and doesn't know that UVA does go through glass? And he thinks regular glass stops all UV rays?? tsk tsk...

You should confiscate his diploma!
An interesting demonstration to do is to take a sheet of paper and a piece of regular glass and UV glass. Put the glass on the paper and then shine a "black" light on them. The plain paper will be almost glowing, reflecting the light. The paper under the plain glass will 'glow' a little less. The UV glass will be almost black.
Correct Hanna,

I use a 366nm black light (a lot) to demo Guardian UV vs plain glass to framers, and usually we grab a piece of handy A4 paper for this.

A while ago on such a demo, we just picked up a piece of foamcore, and it must have been rag paper . . . it didn't want to glow purple, that's for sure.
Had us stumped, because we then got a piece of white printer paper and the demo was very normal.

Only found out why this occured a few meeks ago, when a couple of the big boys from Peterboro came through for a trade night, and the info about brighteners was discussed.
What I find most interesting with discussions such as this is the lack of discussion and/or recognition of the other factors that contribute to fading.

First of all, LIGHT, not just UV light contributes to fading. So, just because you use an ultraviolet filtering medium (glass or acrylic, laminate, spray or top coat) you will not prevent fading caused by light. You may slow it down or stop the fading caused within a specific wavelegnth, but all light causes fading.

Secondly there is heat, and thirdly changes in humidity.

I think there is a fourth one that was not discussed when the original criteria were established, and that is ozone, which has been demonstrated to be a major cause of ink-jet fading. In fact, most of Epson's longevity specifications are for items framed under glass.

Ironically, Wilhelm Imaging Research specifically states that "covering a print with an additional UV filter, or spraying it with a UV absorbing lacquer, will do little if any good in reducing the rate of fading during display." Of course they were limiting their discussion to "modern color papers," and were not including ink-jet prints, however, Tru-Vue and other UV glass manufacturers have never made framers aware of the WIR conclusions.
Interesting thoughts you have . . .

Other data I have on file is about PRD (Probable Relative Damage) that shows :

Damage from light at 500nm (fully visible light) is rated at 0.03 PRD.

Damage from light at 380nm (UVA light) is rated at 1.00 PRD.

Damage from light at 3000nm (UVA light) is rated at 8.00 PRD.
* Some 266 times the 500nm level. *

Sure, I have learned a lot about different reactions when testing.
Modern inks can make UV protection almost a waste of money, but this is almost impossible to tell until you do a test.

Certainly heat and humidity play a big part in damage that can occur.
When UV light enters a framing package, moisture (ever present, and impossible to exclude form a framing package) reacts and causes chemical reactions, creating acidic material (I think it's hydrogen peroxide) that is terribly damaging especially to paper and textiles.

Most likely, the important thing is to do what is going to offer the BEST protection possible, where preservation is determined to be desirable for a particular job.

Anyway, ever learning along the way.
Although I am more than ready to accept Les’ descriptions of UV A and UV B filtration, your Dartmouth grad may not be so inclined.

If you present him with information that debunks his beliefs, he may not forgive you for making him look foolish. You may lose him as a customer.

If ignorance is bliss, keep him happy!
Well, at least UV rays are easy to reduce in the overall equation. Sure, UV blocking glass won't make the print last forever, but it will keep it looking nice longer, and is only a little extra work to apply.

It is only part of the package, after all. Inert matting and mounting materials, dust and insect exclusion, and other aspects of preservation all work together. It would be silly to use UV blocking glass with acidic mats.

I suppose you could say that Chemistry is more important to this than Physics.
I might not shallantly say "look you were right. I found this pamflet that the glass people make and it goes into more detail. I thought you might like to take a look. I found it fascinating since I have not been so involved in phsysics like yourself".

The odds are 50-50 that he will not come back anymore as he now thinks you are ignorant of what you speak. He laughed right in your face and belittled you which means he has little respect for you now.
So, in reality, you have nothing to lose by showing him that you are not only capable of admitting ingnorance on your part but also have the desire to learn the truth which you are now more than willing to share with him.

It is not your job to keep your customer "blissfully ignorant" but to ensure they have the truth as you know now.
Bill The grad can be as blissful as he wishes to be with erroneous belief that his degree made him infallible. However he also spotted off his KIA Degree in front of a good customer that Judge Roy bean says he always sells UV protective glass to. It is just this sort of Pompous arrogance from People like this Grad and others in the industry that make truly caring and information seeking FRAMERS look like a bunch of Charlatans.

I would definitely correct the errors he made but most importantly I would correct them with the GOOD customer and maybe in any NEWSLETTER I published with out even mentioning the grad by name. Sometimes repeating arrogant errors over and over cause them to be picked up and excepted as fact when actually what they are or half correct MYTHS .I think we even see a fair amount of all these bad Hypothesis here on TFG from what should be knowledgeable Framers.And then we wonder where the Framimg Myths originate from and why.
Yeah, you’re right; he should be told.

I guess if you approach it, “Well, it looks like we can both learn something … “

I would probably upgrade the glass without charge to lessen the embarrassment he might feel.
Rob I intentionally waited a bit to see some comments before adding my .02. As I suspected, your points are largely blown off. That is because the admonition that UV glass has some rather severe limitations doesn’t make it an easy sell.

The customer in question has a valid point. If the UV glass isn’t going to “stop” fading and it costs at least double, then it’s certainly worthy of consideration.

I have some serious first hand issues with this glass. This isn’t an inclusive list but why are the demos from TruVue fake? At my first shop, that had virtually no UV light (florescent or sun), did items fade with and without UV glass? Why haven’t I been able to reproduce the TruVue demo with various items?

Buddy, I agree completely. With phrases like “The cost is insignificant” or “its like sunscreen for your art” we are giving false information. I’ll bet many framers that worship at the UV altar never mention heat (which certainly caused the fading in my first store) and the other factors Rob mentioned. A common discussion in my shop goes like this: “I can only do so much to slow aging of paper on display. The best way to preserve this is NOT in a frame, any frame.” Informing the customer that under ANY condition framing will ruin the piece gives me peace. Not one customer has walked and several has opted to reproduce the item$. And a black light? Fagetaboutit!

This customer’s delivery might have totally sucked but his concerns are valid. Sure he wasn’t totally accurate but neither is many of the claims I read here. Its funny how many won’t touch Artcare Restore because of its unknown limitations but sell UV glass religiously ignoring its known limitations. It would be a struggle with me but I would certainly try to avoid his arrogance with more of the same. With the long weekend coming up, I think I could today anyway.