I just believed it was important to address the entire UV portion so those that have knowledge of the EMS, but not solar films, would come away from your reading a bit less perplexed.

dext

Let me just address this part:

“Correction:
The solar spectrum begins at ‘0′. 300nm is in the UVA band leading downward through UVB and UVC until arriving at 0.”

Yes it does Dexter, but when we are dealing with film we only deal with the wavelengths that reach the earth’s surface. So when we factor in the atmosphere that blocks the smaller wavelengths, the UVC band (100-280nm) and glass that blocks almost all the UVB (280-320nm)that leaves us at about 300nm plus that actually transmits through glass. Thus when we test film we do not necessarily have to account for what is already filtered out by atmosphere and glass so therefore I did not account for it in this article. If I did though, someone would come along and probably tell me “why account for what is already filter out?” -lol

-vc

BTU meters measure all UV (granted UVA), visible light range and as mentioned only a small portion of the infrared band. It in no way compares to the accuracy found in lab photo spectrometers.

Quote “No, the solar spectrum starts at around 300nm and extends past 2500nm.” Unquote

Correction:
The solar spectrum begins at ‘0′. 300nm is in the UVA band leading downward through UVB and UVC until arriving at 0.