Opinions Wanted Premium Clear Acrylic - What is the UV Protection %

Larry Peterson

SPFG, Supreme Picture Framing God
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I'm confused.................a bit more than usual.

I have always believed that the UV protection for Premium Clear Acrylic is 66%. That's what TruVue states on their site. I can't find anything for Evonics FF3 anywhere. I have seen a couple of things lately where folk are claiming 90% plus UV protection for their acrylic without anything to back up their claims.

In the WireCutter article mentioned in another thread - https://www.nytimes.com/wirecutter/reviews/best-online-framing-services/ The Best Online Framing Services they state that their UV Protection for Framebridge regular acrylic is 92% although I can't find anything about this on their site.

In addition I have seen some vendors on Etsy state their regular acrylic is 92% protection also.

I can't find anything,anywhere that validates this.

What I have found is this:

With impeccable clarity, excellent weatherability, and high light transmission, this plastic has no additives to block the transmission of UV light. While UV filtering acrylic blocks up to 98% of UV rays, UV transmitting acrylic allows up to 92% UV ray transmission.

I have also seen :

Colorless ACRYLITE acrylic sheet has a light transmittance of 92%,

None of the literature I have read mentions ANYTHING AT ALL about UV Protection of Premium Clear/FF3 acrylic leading me to believe that folk are reading the 92% light transmission number as UV Protection and falsely misleading folk into believing that Clear Acrylic has a high degree of UV protection.

Can anyone shed any more light (pun intended) on this?

If I can find some further clarification on this and that folk are misleading dolk I will update my page on Misleading Acrylic terms at https://www.thepaperframer.com/misleading.php Misleading Acrylic Terms
 
This is a can of worms. I have tested various UV filtering products and found they vary widely in their ability to filter out UV. One manufacturer claimed better then 90% but when tested it only filtered to around 60% (going by memory). When I wrote and queried this I was told it was "within manufacturing tolerances". I cannot think of any other industry with such wide "tolerances". Imagine if your car was made with such inaccuracy!

Most manufacturers define UV as having a shorter wavelength than 380 nm, whereas conservators measure it from 400 nm. This gap enables manufacturers to claim an efficiency of 90%, 92%, 99% (for example) while ignoring the longest wavelength UV - which still causes fading.
 
UV light covers a wavelength spectrum from 100 to 380 nm and is subdivided into three regions by wavelength: UVA (320 to 400 nm), UVB (280 to 320 nm), and UVC (200 to 280 nm) (1). Among them, UVC has the strongest germicidal effect and is widely used in the form of mercury lamps to inactivate microorganisms.
https://www.ncbi.nlm.nih.gov/pmc/ar...h,mercury lamps to inactivate microorganisms.

Using UVC Light-Emitting Diodes at Wavelengths of 266 to ...

According to this site, UV is from 100-380 nm, but UVA to 320-400 nm.
Conflicting information.
 
UV light covers a wavelength spectrum from 100 to 380 nm and is subdivided into three regions by wavelength: UVA (320 to 400 nm), UVB (280 to 320 nm), and UVC (200 to 280 nm) (1). Among them, UVC has the strongest germicidal effect and is widely used in the form of mercury lamps to inactivate microorganisms.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4702654/#:~:text=UV light covers a wavelength,mercury lamps to inactivate microorganisms.

Using UVC Light-Emitting Diodes at Wavelengths of 266 to ...

According to this site, UV is from 100-380 nm, but UVA to 320-400 nm.
Conflicting information.
If you are interested in minimising fading and look at the conservation literature then 400 nm is the cut off.

The last time I tested the TruVue products they were pretty good but manufacturers do tend to tweak the product over time so I really need to re-test.
 
Please know that you can filter out 100% of "the harmful UV rays" and the artwork will still fade from the rest of the light spectrum. Read the ads and literature carefully! Yes, it's the best we can do as framers but still advise your customers to keep their art away from direct bight lights. That's why art museums are quite dark.
 
Indeed, the artwork will still fade - but the fate of fading (all other factors being equal) will be much very slower without any UV.
The contribution of the UV to fading is disproportionately great due to the fact that the energy increases as the wavelength gets shorter. In other words the red end of the visible spectrum has the lowest energy and the violet end has the highest energy. UV, being beyond the violet end, has even greater energy. This energy initiates the fading reactions.
 
I would keep it simple, there’s so called UV filtering glass and there is conservation glass.

Conservation glass can of course also be called uv filtering glass but it there is a a spec for it, and an ISO. It should filter a minimum of 97% of UV within a stated range - and absorptively, not reflectively.

Anything I’ve ever seen claiming these quite impressive numbers up to 92 are reflective, and those numbers only work with head on light, the numbers reduce as the angle changes.

Think conservation or non conservation, regardless of claims given in % of filtering.
 
Unfortunately it isn't as simple as that. "UV filtering glass" and "conservation glass" are not legally defined terms here in the UK. What is important is how much, or rather how little, UV reaches the artwork. The various products on the market vary dramatically in how much UV they filter out. The % claimed is often much higher than the % actually removed.
 
I’m in uk too and I don’t think there are any terms within the trade either side of the pond that could be deemed legal or illegal, unless it’s a downright lie!

I’m just saying there is an ISO for conservation glass (or “glazing” - as this thread is about acrylic really) and the stuff that meets it offers more protection than a whole load of products making big misleading claims that don’t.

“Conservation” or “non-conservation”
works for me, regards glazing or any other framing material, methods too.
 
It could be this product:

It is that product. While it says it "Offers excellent UV protection", it FAILS to state what % that UV Protection is. Why state Excellent that then fail to quantify it? My original question still stands. WHAT % is the UV PROTECTION OF FF3 ACRYLIC?

TruVue states their Premium Clear has 66% UV Protection. How can FF3 which should be the same product from a different manufacture have a much higher %? I have always used the two interchangeably. Should I not?
 
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