Datacolor User to User Support Group.

In a message dated 3/15/06 7:15:40 PM, lowlife_inc@... writes:


> OK, that was an extremely informative thread, especially thinks to
> David Tobie.
> 
Actually, it was a zoo, but there was some good info in there, for those 
willing to wade through. Thats how these groups are...
> 
> Now, allow me to me rephrase the main question.
> 
> "Assuming that the two monitors can be independantly calibrated" 
> 
Only one nit to pick so far: Independently calibrated and independantly 
profiled, or independantly calibrated and jointly profiled? This detail will effect 
the best choice of workflow...

> what
> is the best way to achieve visually matching colors on both monitors
> using Spyder2 Pro software? For my purposes the monitors are identical
> LCD, but I would like to know a more general answer as well.
> 
> Here's my guess: calibrate both monitors and chose the "best".
> 
Think of a motorcycle gang. We think of them as outlaws with no rules, but if 
the goal is for each of them to drive as fast as then can, they won't be a 
gang for long, they'll be spread out over several counties. So they have to 
actually travel at the rate of the slowest, not the fastest, bike. Same with 
monitors. You can't make several   monitors match the "best'; you can only make 
them match the worst. That means the weakest (highest) black luminance target, 
the weakest (lowest) whitepoint, at a whitebalance that the weakest monitor can 
manage. This is why, when I'm told to "match all the monitors in the whole 
office" I have to point out that this would mean the color correction screens 
will be as dull and dim as the secretary's monitor unless we use a bit more 
logical standard. You need to avoid, in most cases, dulling LCDs down to match 
CRTs, or the LCD owners will rebel. You need to check all the monitors, calibrate 
and profile them INDEPENDANTLY once, to see what their specs are, then find 
the group that you are willing to compromise to a single, literal standard.

For two monitors this means to look at the info, see what the native black 
point of each is, and set the weaker as the standard. Look at max white 
luminance, and not set a white target above what either can reach. You may, for a 
range of reasons, set a white luminance target that is lower than the max on 
either. This will give you headroom so that you can continue to calibrate to this 
consistant standard as both monitors fade. And the max may be too bright for 
your ambient lighting and your proofing lighting. I'll post a page from the new 
Ambient Light feature help to the files section for those interested in the 
relationship between whitepoint, white luminance, and ambient lighting.

Once you have an appropriate target both monitors can reach, you calibrate in 
the advanced mode that uses target white and black luminance, as well as the 
same gamma and whitepoint for both, and unless you run into special problems, 
you're done.



>  Save
> it's settings as a target. Load this target for the second monitor and
> recalibrate it. 
> 
Other than using the weaker, not the stronger of the two, and sometime the 
black from one and the white from another, thats the general idea.

> Adjust RGB sliders in the process ignoring the
> software warning. You can use this target file for other computers as
> well.
> 
See issues above, but yes, you can. And yes, you can force the whitepoint for 
a side by side match.
> 
> I am specifically interested in visually color matching two monitors.
> 
Well, the last item would be profiling both and using both profiles, as any 
color variation between the primaries on the two screens will turn around and 
bite you if you can't do this...
> 
> By now I have a very good understanding of XP color issues but please
> let's leave it aside. My next computer would be PCIe regardless of the
> color management issue. For the time being I'll settle for the best I
> can have under the circumstances.
> 
> Within those limitations, I think the above description covers it. Now I have 
to remember to copy that help file to the files section...

C. David Tobie
Product Technology Manager
ColorVision Business Unit
Datacolor Inc.
CDTobie@...
www.colorvision.com