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Old July 14th, 2014, 05:16 PM
Doug Kerr Doug Kerr is offline
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Join Date: May 2006
Location: Alamogordo, New Mexico, USA
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Default The Windows monitor calibration tool - dull at best

I discovered just yesterday that Windows 7 includes provision for taking LUT data used for monitor calibration from the "caboose" on the applicable ICC profile file and loading it into the LUT in the video card (rather than our having to have some accessory to a monitor "calibration" program do that for us).

As an offshoot of that, I also discovered that Windows 7 has a built-in provision for calibration of the monitor without benefit of any instruments.

This afternoon, I decided I would see just what this is.

It is gravely agricultural.

The first test is for setting the display chain gamma, using an onscreen slider. This is an interesting variant on the familiar scheme for doing this visually. It "functioned" (I was not able to easily determine how accurate was the result).

The next two tests were for setting the monitor brightness and contrast using its own controls. For brightness, we are first shown three small versions of a shot of a fellow in a black suit with a not-quite-so black shirt holding a sheet of white paper, apparently in front of a dark background with a slightly-less dark "X" on it. The three images are described as "too dark", "good brightness", and "too bright". (You know, just like in the Three Bears.) (On my display, on the left and middle one I cannot see the dark-on-darker "X".)

We are told to (at the next step) try and get the image to look like the middle of these.

In the next step itself we are shown the image larger, and asked to change the brightness control on the monitor until we can distinguish the shirt from the suit and just barely see the "X" against the background.
Of course on an LCD monitor, where the brightness control affects the luminance of the backlight, that actually has almost no effect on those matters.
Then, for contrast, we are first shown three small versions of a shot of this same fellow, now with a wrinkled white shirt, standing next to a panel with a black and white portion, across which is a vertical line, black where the panel is white and vice-versa. They are designated "not enough contrast", "good contrast", and "too much contrast". We are told to (in the next step) try and get the image to look like the middle of these. On it and the leftmost one, on my system, I can clearly see the wrinkles on the shirt; they are less visible on the rightmost one.

In the next step itself, we are shown the image larger, and asked to set the brightness control on the monitor as high as possible and still be able to see the wrinkles and white buttons on the shirt.

Next, we get to set the gain of the R, G, and B channels with three onscreen sliders, looking at a pattern of five bars of varying luminance. We are told to set the sliders until we see no color cast. We are not told to have one of the sliders at maximum (as would be appropriate).

This probably, at best, very approximately sets the white point of the display to the white point of the ambient illumination at our computer.

And that's it.

This appears to demonstrate that the wizards at Microsoft, starting with only dirt and water, are able to make -- mud.

I hardly know what to say, other than "don't bother".

Best regards,

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