[argyllcms] Re: FWA Compensation

  • From: <robert@xxxxxxxxxxxxxxxxxx>
  • To: <argyllcms@xxxxxxxxxxxxx>
  • Date: Mon, 8 Dec 2014 17:45:55 -0000

Graeme Gill wrote >

>> The illuminant is a D65 fluorescent and the paper is a Permajet Oyster.

>By "D65" I guess you mean D65 white point, not D65 spectrum. The most
>critical aspect is the UV content of the illuminant spectrum used in
>the calculations. That has to be approximately right in order for FWA
>compensation to work.

Yes, when I say D65 I really meant around 6500K - it's just a standard tube
not manufactured for proofing.

>> Looking at the SPD of the paper it does seem that it has a lot of FWA as
>> there is quite a big hump around 400nm.  I don't know how much UV is in
the
>> lamp.  Could you tell me how I can estimate this doing an M1/M2
measurement?
>> (using spotread, I assume?).

>That is what illumread is for:

Yes, I did use illumread of course as FWA compensation requires it.  You can
see the SPD plots here:
http://www.irelandupclose.com/customer/LL/IllumRead-Fluorescent-D65.jpg

I also ran illumread with an early morning blue sky (winter, Ireland) which
I would have expected would have a fair amount of UV and this is what I got:

http://www.irelandupclose.com/customer/LL/morning-blue-sky-permajet-oyster.j
pg

I don't know how to interpret these results to give me an indication of UV
content in the illuminant.

Robert


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