Re: Optical/Spider black and white target points?
Re: Optical/Spider black and white target points?
- Subject: Re: Optical/Spider black and white target points?
- From: Roger Breton <email@hidden>
- Date: Mon, 29 Sep 2003 07:48:36 -0400
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"It is preferred with Windows PC's that the Spyder be plugged into a
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separate PCI USB card rather than into USB ports built into the
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motherboard."
That's the first time I hear such a statement?
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Anyone know why the USB ports on a contemporary motherboard might be
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considered inappropriate for using hardware calibration devices?
I am not personally aware of any such differences.
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I also wonder about the Spyder's .30 black 'precision mode' target
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setting in the previous version of Optical? In Real World Color
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management there's a test for the black point outlined which suggests
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raising and lowering the black value of a selected area of a 100%
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black image in RGB and noting whether a difference can be seen when
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lightening 1 to 2% while using the monitor colorspace. With a
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blackpoint target of .30 I easily see a difference between 0 and 1
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and continue to see a difference if I set my brightness even lower.
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Is .30 is too high? I'm using a Mitsubishi DPro2040u.
I think you want to set as low as you possibly can. The lower you set it the
higher the Luminance Ratio (from white to black). 0.30 is by all means a
very satisfactory setting if you feel you can achieve it reliably. You can
find out more about this setting (and a host of other specifications too) by
getting your hands on the latest ISO-12646 standard called "Graphic
technology -- displays for colour proofing -- characteristics and viewing
conditions". To answer your above question, Section 4.8 says that "the black
point shall have a luminance that is less than 1% of the maximum luminance
(i.e. A luminance ratio that is a least 100:1)".
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With the most recent version of Optical I now note that there are NO
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longer any preset default settings for white or black points and when
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I select proceed the suggested defaults are .19 and 88. Is the
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visual target offered by Precal perhaps more accurate than any pre-
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defined measurement? Does this also suggest that the old 80 luminance
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was too low? The Precal suggested luminance range for the RGB color
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guns in 85-95. Is higher better? I'm not matching multiple monitors
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in a group workspace.
Again, quoting from ISO-12646, Section 4.8, "The luminance level should be
as high as practical but shall be at least 80 Cd/m2 and should be at least
120 Cd/m2". Why the two specifications? I don't know.
The ambient illumination conditions are very important. You don't want to
operate your CRT is full daylight. I think the standard calls for less than
32 lux, and even less.
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So many questions ;-)
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Thanks for any answers.
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Russell Proulx
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Montreal, CANADA
Regards,
Roger Breton | Laval, Canada | email@hidden
http://pages.infinit.net/graxx
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