[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: color temp puzzle



In response to Mikael Reichel:

> Not knowing anything about this instrument I can only make a guess that =
> this unit has been designed to respond correctly to the spectral content =
> of the phosphors used in the monitor. Guessing again, it  possible to =
> have less accurate (discriminating) filters if you know the spectral =
> origin of what you are going to measure. Thats why, if you point the =
> meter to another spectral source it will read wrong.
>
> /mike reichel


So the answer then would be to use a spectroradiometer as suggested by the CIE
instead of a colortemperature meter?  Who is using this to calilbrate monitors?
 Anybody?

See, the goal is this.  I would like a white field on the monitor, both SGI and
regular Video/RGB/NTSC to "look/feel" the same as my surrounding lightsources,
as well for example a filmscreen...

This is what Jonathan E. Hardis <jhardis at nist.gov> from CIE USA wrote:
"...if the metrology was perfect, the term "color temperature"
as commonly used does not mean "color."  Things can have the same color
temperature -- more properly called the "correlated color temperature" --
and have different color.  For CRTs, in particular, the specification is
often in terms of both degrees K (correlated color temperature) and the
extent to which the color is off of the Planckian locus..."

This is what Dr. Janos Makai <ciecb at ping.at>, CIE Technical Manager had to add:
"...As Jonathan has pointed out the same correlated colour temperature does not
mean  the same colour. For your task it is advisable to use a spectroradiometer
which  can calculate both the colour (chromaticity coordinates) and the
correlated colour temperature. This should give accurate data on your CRT and
lamp, too.



-- 
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
If you want to understand the causes that existed in the past,
look at the results as they are manifested in the present.  
And if you want to understand what results will be manifested
in the future, look at the causes that exist in the present.
                                               N.D.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
~  Tarcis Verfaillie				              ~
~  Colorist/Compositor		Digital Domain                ~
~					300 Rose Ave.         ~
~					Venice, CA 90291      ~
~					310-314 2977          ~
~					tarcis at d2.com         ~
~					http://www.d2.com     ~
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

---
Thanks to The Post Group for support in 1998.
No product marketing allowed on the main TIG.  Contact rob at alegria.com
1010 subscribers in 39 countries on Thu Sep 10 14:57:24 CDT 1998 
subscribe/unsubscribe with that Subject: to telecine-request at alegria.com
complete information on the TIG website http://www.alegria.com/tig3/