Re: luninance settings in optical
Re: luninance settings in optical
- Subject: Re: luninance settings in optical
- From: email@hidden
- Date: Tue, 18 Dec 2001 11:48:12 EST
In a message dated 12/18/01 3:31:59 AM, email@hidden writes:
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In Optical 3.5 I now find an option to change the white
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and black target luminance.
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I looked through the manual but didn't find how
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to handle this option.
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I guess those values that are set there should be good
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to go but I am wondering about when there would
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be a neccessity to change them.
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Anyone ?
Reading black with a luminance sensor is a bit like counting to infinity,
while waiting for no photons of light to hit the sensor. So setting the black
point a fraction above absolute black (which is what the default setting
does) offers to make your black a bit less black, but in return it brings the
light levels up to a range where they are more accurately readable. So the
result should be a smoother, more accurate ramp at the dark end, but a slight
loss of darkness.
The white luminance issue is one we are bound to hear lots about in the near
future, with new standars of light box luminance being proposed, and with LCD
monitors changing the basic logic for limiting monitor luminance. At the
moment I would think a safe statement would be to limit CRTs to the classic
prepress range of 85 to 95 candelas per square meter to avoid premature
burnout, and to allow a whole studio of them to make the same target
luminance (there's bound to be at least one that won't make some higher
level), and to match your LCDs to that if you have a mixed environment,
sharing the same proofing lights and background illumination.
If you are using LCDs on their own, then the sky is the limit; with the
practical limit to white luminance being set by the brightness of the
proofing illumination of the paper you wish to match; if your m print! But I
suspect that brighter proofing lights, balanced with LCD monitors at higher
luminance levels, thus allowing more humane background light levels, will
become more common in the near future. I'm currently running my LCDs at some
scandalous three digit luminance level... <G>
C. David Tobie
Design Cooperative
email@hidden