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Hi,
1) Color patches…I want the best possible calibration and profile for for my displays when I use Photoshop and Lightroom…How many patches should I use…Is there a fall off point (for hdtv or computer monitor) where more tiles make no difference? Where is that point? Is there a minium point? Where is that point?
There’s definitely a point of diminishing returns, and for most displays this is around 2000-3000 patches. The minimum amount of patches you can set for an accurate cLUT-based profile using the “Auto” testchart setting (which should be used for best results) is around 425 patches, which in most cases results in a decent profile but I would consider the “low end”. More patches increase the accuracy. The “sweet spot” of time spent measuring vs profile accuracy is around 1000 patches (depending on instrument and user patience).
(2) If I want to change the brightness of my HDTV to match room lighting (Say 120)) then wouldn’t this change my pre-calibration of the tv’s white point such that the resulting calibration would have grayer whites? … Isn’t the point to maximize the whitepoint of the tv’s capibilities? … Can I or should I instead use the tv’s backlight to change the brightness of the screen because it will leave my pre-calibrated whites alone?
You should set brightness according to your lighting situation. In a bright room, 120 may be too less, in a very dark room it may be too much. Do not focus on a specific value too much.
Then this begs the question about my computer monitor. It doesn’t have a backlight setting so I must use the brightness adjustment
The “brightness” control on many computer monitors actually controls the backlight (and if implenented cleanly, this is the only thing it affects). “Contrast” on the other hand should be left alone (factory default) for most computer monitors (not TVs) because there’s often only one correct setting, anything else will either clip or reduce contrast at the digital signal level.
(3) How do I get the Windows 10 desktop to use the calibration so everything I see on the screen is color correct?
The Windows desktop is not color managed, and the calibration is just 1D curves so that alone is not enough for accurate colors. Only color managed applications that are aware of and can use ICC profiles will be color-correct.
(3) Does Photoshop and Lightroom use 3DLUTs? Do I want 3D LUTs? Is it automatically implemented or do I need to change any settings in these programs first. If so, what are the changes?
Photoshop and Lightroom make use of ICC color management for color correct display and output, so there is no need for 3D LUTs. All that is required for this to work is a display profile installed in the operating system and assigned to the monitor in question (dispcalGUI does this work for you).
What about the Calibration time slider? Is there a law of diminishing returns there too? Where is the ‘sweet spot’ there?
The answer to that is “yes” and “medium” 🙂
And finally (For today anyway) Is the purpose of the ‘Verification” to see if the calibrationprofile has ‘slipped’ over time … Or more accurately, the monitor has changed it’s output in some way.
That, and to check how accurate the profile is (right after it has been created). There are also a few more advanced use cases, see the documentation in the ReadMe.
does the display type dropdown box make that much difference in the final outcome? I used ‘Generic LCD’ when I should have used ‘LED (White)
Depends on the instrument, but generally it’s a good idea to set an appropriate display type and/or correction.
