On Sunday, August 10, 2003, at 07:50 pm, Thomas Holm / Pixl wrote:
Bob Croxford wrote:
A viewing booth is only an expensive way of producing what is coming in your window for free, daylight. Real daylight will always be 100% better than anything that comes out of a fluo tube.
Bob, I politely disagree:
Most of the graphic arts have standardisen on a specific daylight (D50) to
be able to have a specific defined lightsourcs, as opposed to daylight. The
spectral properties in daylight can vary a great deal, and pending on the
high wavelength component optical brightener in a paper will be triggered by
different amounts changing not only amount of apparent light but also the
colour that the eye use as white point.
A viewing booth of verified quality is the only way to be able to see the
same colour at different locations. Full Stop.
but "daylight" as a concept is much too elusive to be used to evaluate colour,
especially if you want others to see things the way you did...
Best Regards
Thomas Holm / Pixl ApS
Dear Thomas
Perhaps I did not make myself clear originally. I understood William to ask about comparing an evaluation print against a proof print or final output print. To compare one print against another it doesn't really need to be a defined D50 source, just something in which the eye can function correctly and compare colours. Conveniently the human eye has its own white balance and is designed specifically for working in real daylight.
I agree that a standard is needed to evaluate the first copy and to view it in conditions when daylight is not available. It is when you have two copies to compare that daylight is a cheaper alternative and perfectly adequate.
It was when comparing base paper colours that I first realised the limitations of viewing booths. Some papers could look warmer or cooler than other papers depending on where they were viewed. However I found that the papers I was evaluating always had a consistent relationship to each other in real daylight. If an optical brightener or kaolin coating does not look right under a fluo tube but does in daylight one has to go with the conditions under which most people will view the finished result.
Daylight as a colour for photography was defined as the colour at noon in Washington in mid summer. I think the chance of anyone taking any of our work to Washington to view it is remote. ;-)
Yours
Bob
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