Re: Display colours with photocal on LCD
Re: Display colours with photocal on LCD
- Subject: Re: Display colours with photocal on LCD
- From: email@hidden
- Date: Fri, 29 Nov 2002 12:50:51 EST
In a message dated 11/27/02 2:13:23 PM, email@hidden writes:
In a message dated 11/27/02 2:13:23 PM, email@hidden writes:
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Well, I've been rethinking my Spyder purchase after using it. First I
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profiled the LCD (aka: LittleApple) before I moved on to the 21" Sony
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(aka: BigSony). I don't have any comparisons to make regarding the
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LCD, since I've never profiled one before, but, correct or not, here's
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what I did....
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Right off the bat, I noticed that between the hanger strap and the
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Spyder's distortable rubber cup, the device did not hang flat against
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the screen (hanger) and had wide gaps in its ambient light blockage
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(rubber cup). I removed the cup and worked with it a while to get it
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more symmetrical, then I tilted the display waaaay back (think of
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getting eye drops at your optometrist), and finally turned the room
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lights out because it still wasn't 100%.
The rubber ring is only uses with the suction cups on glass CRT screens,
where it is pulled flat through suction. It is never used with the hanger on
LCDs where the triangular LCD fitting is used instead.
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There aren't many controls on the LCD, but I did choose a 6500 White
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Point from the display's menu. I opened OptiCal, selected LittleApple,
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checked LCD, and left the other selections at their default "Gamma
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1.8", "Native White Point", and luminance values of "1.0" and "200.0".
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Then I just clicked "Calibrate". As I said, I don't know if my
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selections were the best ones, or if these same options are available
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in PhotoCal - I've never used the program. This is how I came up with
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a profile that was pretty identical to A98 and ColorMatch when swapped
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around in the Displays Preferences - at least when rendering my gray
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desktop.
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Then I swapped the Spyder's foot from the rubber cup to the CRT's, and
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began my standard PreCal/OptiCal routine on BigSony.
Teh rubber cup *is* the CRT base, the triangular one is for LCDs...
If you haven't
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worked with this combination, first you run PreCal, setting your target
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white point in PreCal (6500 in my case). Then, with the Spyder
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attached, you measure and adjust the display's RGB levels to that white
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point through the monitors own controls.
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With my old OS9/Pre-OptiCal/DTP92 setup I could always get the color
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levels adjusted to the point where the DeltaE difference with my chosen
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white point was 0.00. Once I got to 0.00, I'd double-check the color
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temp another half-dozen times, and maybe on one of those
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re-measurements I'd get a slight deviation to about 0.78. Most of the
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time, however, it would stay rock-solid at 0.00.
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When I did the PreCal routine with the Spyder, the first thing I
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noticed (same monitor settings as my last calibration in OS9) was that
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the monitor's brightness, which was set at 95 cd/m, was now reading 126
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cd/m. Strange.
If you have the wrong base on your Spyder, this woud not be strange at all...
Then, when I began adjusting the guns to the white
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point, the Spyder's readings were all over the place. I could get the
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DeltaE to 0.00, but the second reading would be 2.46, the third 0.78,
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fourth reading 0.74, fifth time 1.34, and on and on and on. Basically,
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what I was getting from the Spyder in PreCal was meaningless.
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However, I did the best that I could and moved on to the OptiCal
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profiling. I set BigSony's OptiCal options as I always had: Gamma 2.2,
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White Point 6500, and Luminance 0.3 and 95.0. But when I began the
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calibration process, after the first patch or two, I got a dialog
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telling me that BigSony was not a CRT, but had the characteristics of
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an LCD (BTW, CRT was the checked option under Monitor).
Right, because you had the wrong base on it...
I rechecked
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settings and repeated several times, but always got the same response.
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Forging on, I clicked "Continue" and soon came to the screen where
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black level is adjusted to 0.30 by using the monitor's brightness
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control. The bar was pegged to the right, but when I started to lower
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the monitor's brightness, I could only get it down to 0.46. One click
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less would drop it to no reading at all. That was it - 0.46 or nothing.
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It was also a bit of a trick to get the Spyder to attach to the glass.
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The triangular light baffle extends far enough past the suction cups
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that it was a real job getting all three of them to stick.
They are not supposed to stick while the CRT baffle is in place, thats the
point...
I had to
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force-bend the clear plastic feet and use a lot of spit to keep the
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Spyder from popping a foot off.
Spyder abuse...
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One difference between the good 'ol OS9/Pre-OptiCal/DTP92 days and the
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new OSX/Pre-OptiCal v3.7/Spyder setup, is that during my move to OSX, I
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got caught in the ATI PCI/non-ATI AGP system bug-crash, and had to
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replace my nVIDIA GeForce3 AGP card with an ATI 8500. But would a
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different card make such a difference in brightness and stability?
No, using the wrong attachment to the Spyder would be responsible for that,
its in big pictures on the screen to attempt to avoid errors like this...
I'm
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going to see if I can boot back into OS9 and check with the DTP92.
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Anyway, that's my story. One of the half-million in the this big city.
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Of course names, numbers, and descriptions have been changed to
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protect the innocent.
Try it again with the other attachment, and see what that does for you.
C. David Tobie
Design Cooperative
email@hidden
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