Datacolor User to User Support Group.

Thanks for the thoughtful and detailed response.  Just want to 
make sure I understand how to measure the candelas of my moniter.  I 
think I go to tools/coloritmeter and then take a reading.  Am I 
correct that the  CIE xyY is the candela value?  If not how do I find 
it? 

   Mine measures 122.  Does that mean that's as bright as my moniter 
goes?  

   Please remind me how to measure the ambient light?  

--- In colorvision_group@yahoogroups.com, CDTobie@... wrote:
>
> 
> In a message dated 3/18/07 3:52:05 PM, mkraus1044@... writes:
> 
> 
> > I am designing a new workroom where I will place my computer and
> > moniter.  I use Spyder Pro 2.2 to calibrate my moniter and 
PrintFix Pro
> > 2.1 for my profiles.  Any suggestions on preferences for overhead
> > and/or room lighting which would help in the most reproducible 
and easy
> > calibration.   At this point in time, I could put in pretty much 
what I
> > want.  Flouresecent vs incandescent, color temp, etc. 
> > 
> 
> The first consideration is consistancy. Yes, daylight is a 
wonderful thing 
> that makes us happy and healthy; but it is incompatable with 
serious image 
> editing. You need a room with no window light, or a dead minimum 
once the 
> blinds/drapes whatever are in place.   And the blinds/drapes need 
to be neutral, they 
> can't be glowing purple or orange!
> 
> Next is luminance level. If you are not using a proofing booth, 
then overall 
> room lighting needs to be correct for the brightness of your 
monitor. You 
> don't want to be using your monitor at full brightness; so it will 
remain capable 
> of the same setting over time, and won't burn out prematurely, as 
well as to 
> obtain a reasonable calibration. So no higher than 175 candelas on 
the monitor, 
> with something in the 125 to 150 range being the most reasonable 
choice. Then 
> you can use Spyder2PRO's ambient light feature to measure your room 
light and 
> tell you if its too much, too little, or about right. Basically, if 
it seems 
> somewhat dim, that would balance with a bright LCD, is it seems 
fairly dim, 
> that will match with a moderately bright LCD, and if it seems dim, 
that would 
> balance with a dim LCD or a bright CRT. If it seems like a cave, 
then you have 
> managed standard CRT levels. If you are using a proofing light, 
your ambient 
> can be dimmer, but doesn't have to be. Don't fall into the trap of 
using a 
> totally dark room and a bright LCD, that will cause glare and 
percieved contrast 
> increases that will ruin your print to screen match.
> 
> Next is ambient light color: something in the 5000k to 6000k range 
is best. 
> Something resembling full spectrum (CRI of above 90) is best. But 
your monitor 
> is enough brighter than the room (if you follow the instructions 
above) so the 
> monitor, not the ambient lighting, will define your eye's 
whitepoint.
> 
> Next would come proofing lights, but its a topic unto itself so I'm 
leaving 
> it for last, I'll cover room color next. Munsel gray paint gets a 
lot of 
> airtime; but its TOO DARK for most people's taste Kodak gray card 
gray, on large 
> wall and ceiling areas is quite opressive!). So get some light gray 
paint samples 
> from your paint store, use the spot measure function of PrintFIX 
PRO to 
> measure each sample, and chose the one with the smallest a* and b* 
values. This 
> will give you a light gray paint for the room. If you want to use a 
darker gray 
> below the wainscott line (chairrail) then thats good too, and 
battleship gray 
> floor paint is great for slabs. 
> 
> But all of this paint colors stuff is ignored by many users. If you 
ignore 
> it, then at least go to the efforts of hanging a large piece of 
neutral gray 
> fabric behind your monitor(s) so that there are not bright colors 
biasing your 
> eye while looking at the monitor. Ditto for the viewing box if you 
use one. 
> 
> Guess that brings us to the proofing light issues: get a 5000k 
proofing light 
> of some type, and set it up; ideally perpendicular to the monitors, 
not 
> directly beside them. If you proof under room light, then follow 
these directions 
> using the location where you place prints to view them. Put 
idential B&W test 
> image prints on both whitened and unwhitened sheets of paper in it 
(one sheet 
> Entrada Natural, one Entrada Bright, is good). If your box does not 
offer 
> luminance adjustment, make sure its at least a bit brighter than 
the room lighting; 
> meaning the paper looks dimmer, not brighter, when you withdraw it 
from the 
> box. Compare both prints to the same image in Photoshop softproofed 
to one 
> paper, then the other paper profile (paper white and ink black 
checked, BPC 
> unchecked). 
> 
> Which appears brighter; the monitor, or the print? How is the 
midtone 
> brightness, and the shadow detail. If you have an adjustable box, 
you can work with 
> that control, if not, you have to adjust the backlights on your LCD 
until you 
> have the right balance. If you adjust using the monitor backlights, 
then next 
> you need to recalibrate at your new white luminance level, and 
define that as 
> your target whitepoint for future calibration as well. If you have 
another 
> monitor, it gets set to this same white luminance target as well.
> 
> Is that complicated enough? If not, you can fuss around with the 
difference 
> between the whitened paper proof, and the unwhitened one. 
> 
> As for room lighting to install: you won't need much, so use what 
you like. 
> In a typical office, I have to loosen three out of four bulbs in 
the overhead 
> fluorescent fixtures to get lighting down to even a moderate level, 
the highest 
> level that can be color managed. Consider having two levels of 
lighting 
> available: general (for vacuuming the floor, finding your glasses, 
etc...) and 
> color managed (with just the lights needed for appropriately dim 
ambient 
> lighting).
> 
> C. David Tobie
> Product Technology Manager
> ColorVision Business Unit
> Datacolor Inc.
> CDTobie@...
> www.colorvision.com
> 
> 
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