Gray gradients (grey gradients) and dark/light visiblity for monitor testing and adjustment

Disclaimer: I don't give advice on how to calibrate your monitor and like... I'm not a professional on that field. Use the image if you find it helpful and that's all.

Download test images:

• Gray gradient: gray-gradients.tif (also the same with: red only, green only, blue only)
• "Darkest visible" test: darkest-visible-test.tif
• "Lightest visible" test: lightest-visible-test.tif

Any serious image viewer, like IrfanView (recommended), should be able to open TIF files. Important! When viewing these test images your videocard must be in 16.7M color mode (also known as true color mode, or 24 bit or 32 bit mode). If you use this for monitor testing, no color management should be applied (the files do not contain ICC profile); don't worry, only professional graphic/DTP applications used to do that. In additional, for the grey gradient no image resizing and no projector's geometrical correction should be applied, i.e. one pixel of the image should correspond to one pixel of the current videocard resolution. TFT-s and other displays that have a "native resolution" should be used at their native resolution. Also, you shouldn't have anything light on the display (outside the test image) or else your eyes may become blind to dark grays (Tip: in IrfanView you can switch to fullscreen mode by pressing Enter).

What technical properties can you see on this gray gradient:

• 1st horizontal strip: how uniform the gradient is, i.e. if you see vertical strips in it (mostly problem with TFT-s). 256 pixels wide, 256 gray grades. Note that the transition should not be lineal; search for "gamma" to understand. If you have TFT the gradient can look really ugly; don't worry, it's like that on the most TFT-s. On many TFT-s you can find settings where the gradient looks good, but then you usually sacrifice other quality factors, like color temperature, and it don't worth it (for must of users at least).
• 2nd horizontal strip: the same as the 1st one, just zoomed. Hence, the dearkness is changed at each 4th pixel column only, so certain kind of vertical strips are OK.
• 3rd, 4th, 5th, 6th horizontal strips:
  • Which grey looks the same as black (3rd strip) or white (6th strip), however for this the other two test images are better. This can be written down exactly with the code of the last and first such grey.
  • If some of the adjoining grades look the same. TFT-s used to do this. This is yet another way of losing from the 256 grades that the videocard sends to the monitor. Note that your eye is able to perceive these color repetations with draker greys only.
• Of course, you can see if black is really black or rather gray/purple (often a problem with TFT-s), and if white has too much of yellow/orange tint (yet another TFT problem).

What can you see on this "darkest/lightest visible" tests: The videocard can display greys with lightness in the 0-255 range (integer numbers only), where 0 corresponds to black and 255 to white. So this is the information it sends to the monitor, but on the monitor the very dark greys often become totally black, and the very light greys often become totally white. This way you lose details in the very dark or very light parts of images respectively. If you watch movies or play dark games the most annoying is losing dark colors. With these test images you can tell the concrete numbers where dark grey was different from black and light grey was different from white.

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