[comp.graphics] Checking temp of a screen

jet@karazm.math.uh.edu ("J. Eric Townsend") (01/29/91)

In article <1991Jan28.010515.708@vixvax.mgi.com> keeney@vixvax.mgi.com (Richard Keeney) writes:
>Use a daylight balanced film - most CRT's are calibrated to have a white
>of 5500 deg. K or so.

How do I check this?  I'm trying to find some way to have our color
images look the same from screen to screen.  I'd love to know how
hot/cold they are so I can just say "gamma +.1 foo.r | display" or
somesuch.


--
J. Eric Townsend - jet@uh.edu - bitnet: jet@UHOU - vox: (713) 749-2120
"It is the cunning of form to veil itself continually in the evidence
of content.  It is the cunning of the code to veil itself and to produce
itself in the obviousness of value." -- Baudrillard

pierce@radius.com (Pierce T. Wetter III) (01/30/91)

>In article <1991Jan28.010515.708@vixvax.mgi.com> keeney@vixvax.mgi.com (Richard Keeney) writes:
>>Use a daylight balanced film - most CRT's are calibrated to have a white
>>of 5500 deg. K or so.

>How do I check this?  I'm trying to find some way to have our color
>images look the same from screen to screen.  I'd love to know how
>hot/cold they are so I can just say "gamma +.1 foo.r | display" or
>somesuch.


     Ahem.

    Most CRT's are calibrated to have a white temp of 9300K, to match
 white monochome displays. TV sets and the like are calibrated to 6500K.


   How to tell the temp of your screen:

     1: Buy a minolta TV color analyzer. This will tell you the chromaticity
        coordinates of the white, and you can compare this to a table to find
        the approximate color temp.

     2: Get a photometer or something that can measure brightness, and 
        measure the brightness of R,G &B. Look up the color coordinates of
        your phosphors, and solve for temp.

    


  How to solve your real problem matching two screens:

    1: if you have a macintosh, buy a radius PrecisionColor calibrator, and
       it will adjust your gamma corrections to match.

    2: Since you don't have a mac, as implied by your unix command above,
       take the backs off your monitor, get a screwdriver, and adjust the
       color balance of all the monitors till they match. Repeat weekly.
       (this is easier with a minolta color analyzer.)

Pierce
       
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