Message
Re: [colorvision_group] Ooops - D65 != D65 ???
2007-06-19 by CDTobie@aol.com
In a message dated 6/18/07 9:03:33 PM, uli@... writes:
Now, I'm aware that (speaking in terms of an xyY chromaticity chart) there's many different
possible (x,y) combinations to produce a 6500 K whitepoint, but as far as I know a D65
whitepoint is an unambiguous standard (x=0.3127, y=0.3290).
Correct...
So I would think it should be reasonable to expect some kind of consistency (at least in the
product range of *one single manufacturer* ...). What's the point of having a standardized
D65 setting if it means something different to each measurement device? That doesn't
exactly build confidence with regard to color management.
D65 always means the same thing. 6500k can mean numerous things. ICC profiles always list (by definition) a D50 whitepoint. There is a document on the ColorVision website on proper transforms for monitor profiles not targetting D50, which has pretty much become the standard for the transforms used to adjust non D50 monitor whitepoints, so that they reconvert as expected. Using different transforms for this would explain differing results, as would minor differences in actual results when calibrating a monitor using different tools.
I'm very puzzled by this experience, and would appreciate comments from the experts in
this forum. Do I expect something unreasonable? Do others experience consistent D65
results and I'm doing something wrong (no idea what that could be, though)?
Don't expect identical results, even from the same tool used twice. Expect somwhat larger variations from differing software, and larger still from differing hardware and software, but all should be within reason. If they are way off, then thats an actual problem, rather than a statistical variation.
C. David Tobie
Product Technology Manager
ColorVision Business Division
DataColor Inc.
CDTobie@...
www.colorvision.com
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