Re: Question about qualifying environment - color temperatures
Re: Question about qualifying environment - color temperatures
- Subject: Re: Question about qualifying environment - color temperatures
- From: Chris Murphy <email@hidden>
- Date: Thu, 14 Nov 2002 09:02:30 -0700
On Tuesday, November 12, 2002, at 12:19 PM, "Kelly, Kristen E"
<email@hidden> writes:
I know that when qualifying an environment before characterization and
calibration takes place the color temperatures of the ambient room
lighting's color temp should match the monitor's white point as well
as the
viewing booth/ viewing area color temperature.
Definitely not. If the monitor's white point is 5000 K and the ambient
lighting is 5000 K and the viewing booth is 5000 K, all three *can*
look completely different. Matching luminosity is more important than
color temperature. That's why calibrating displays to a white point of
6500 K is such a common recommendation. By claibrating to 6500 K, what
you're really doing is allowing a much high level of luminosity of the
display, which ends up being close to that of the light box.
Ambient lighting color temperature can't be 5000 K. First it would be
too bright. And as you reduce the intensity, it would end up looking
way too blue because at low ambient light levels, the rods (not the
cones) become more sensitive to blue light. So in order to approximate
5000 K at more typical lighting levels in a dimly lit room, you might
need something more like 3500 K. And the ambient lighting color
temperature is not that important anyway. ISO 3664 specifies that it
ought not be greater than 64 lux which is not a whole heck of a lot of
light, and probably isn't practical for 8 hours work in such an
environment. I'd concern yourself with just the display and the viewing
box, and get their luminosity to be about the same. The ambient
conditions that are appropriate would be white walls. You can certainly
go with a matte finished gray if you want, but it's probably better to
baffle the viewing box so that you just can't see the floor, ceiling or
walls. As long as while you're working on a workstation you aren't
seeing some crazy pink floor or wall (or equivalent very non-neutral
color), you'll be fine.
Realize too that when final output ends up being compared to a proof
that much higher luminosity is used. ISO 3664 specifies 2000 lux for
critical appraisal (500 for practical evaluation). That additional
amount of light will change the appearance of what you are looking at,
primarily in that saturated colors will become a lot more saturated,
something that is not predicted by the color models we currently use in
ICC based color management. So you basically have to just learn through
experience what's going to happen when prints are viewed under
significantly higher levels of illumination.
My dilemma arises because our monitor color temperature MUST be set at
9300K
in order to get the maximum brightness.
Time to get a new display.
Chris Murphy
Color Remedies (tm)
Boulder, CO
303-415-9932
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