I am sorry if I gave the impression that I was razzing you in any way. Just had a different opinion on the info's usefulness in comparing units of UV energy between different practioneers of carbon printing.

I don't care where you put the horse, but you it seems that you have tried to change horses in mid-steam (going from using the values to compare the exposure times of different practioneers to comparing it to only one's own tissues.)

I can see the usefulness when making one's own tissue. So it sounds like you need a UV meter -- and I guess with such a meter, one would have to assume that the the proportion of the various sections of the UV spectrum remain constant -- if the meter reads UVA, UVB and/or UVC, then hopefully the amount of the UVA (which is what we mainly use to expose with) stays proportionally the same relative to UVB and UVC. Otherwise one is not measuring what actually the material is sensitive to and one might as well use one of the cheap UV "meters" that warns one about sunburning potential -- accruacy will not be needed because one would not be measuring what one is using.

Vaughn