Display black point

The image below allows for examination and correction of a display's black point. It consists of six black regions. Each region contains one almost black digit. The numbers 1 through 6 stand for the digits' so-called Lab luminance. The Lab luminance L* (pronounced L-star) of the L*a*b* color system corresponds better to the differentiation behavior of the human eye than any other color system's luminance and far better than RGB values. This means that the same differences between L* values are also perceived as nearly the same differences by the human eye.

On a decent, correctly set up display you should be able to see all six figures - figure 1 with Lab luminance 1 perhaps only if ambient light is dim, no light is falling directly onto the display and no reflections are disturbing. But actually these are the conditions for image processing, anyway. Additionally, the brightness increase between the figures should be close to linear.

If you cannot or almost cannot see the figures of the lower row (4, 5 and 6), then the black point is set up incorrectly (or the display is trash).

The black point is regulated by the brightness setting of your display (physical knob or screen menu). Push the brightness up until all figures can be seen, but no more! The background should not get much brighter than the totally black screen (i.e. the display turned off or the unlit edges of a CRT screen).



Fullscreen view

Please enlarge this window to fullscreen size and provide for dimmed ambient light without reflexes.

Exact calibration

The calibration image presented here is a Lab image that was converted to sRGB. It was saved as a GIF file, therefore contains no color profile information. Your browser will only render the brightness differences correctly if your display's color space corresponds to sRGB and your system's gamma value is set to 2.2. This is the case with modern displays and Windows PCs even without color management.

For a more exact rendition of brightness differences download the calibration image as a TIFF file and open it with a color-aware application like Photoshop, preserving the color profile. In this case your system's gamma value is insignificant and the calibration image can also be used on Macintosh systems with gamma values set to 1.8.