Calibration_key_terms

Black level

  • Frequently labeled as Brightness on the display
  • An adjustment for setting the intensity of black
  • When set correctly, the lowest level signal above black should be barely visible
  • A quality calibration must optimize the black level for the viewing environment
  • To optimize Dynamic Range, the lower/dimmer the better, as long as don't loose detail in the shadows

White level

  • Frequently labeled as Contrast on the display
  • An adjustment for setting the intensity of white
  • When this is set correctly, the display will not shift in color (no tint), gamma or geometry at high levels
  • Too high a contrast level can cause eye-fatigue, image-retention (IR) or burn-in.
  • A quality calibration must optimize the white level for: maximum high-intensity detail, no gray-scale color shift, and no eye-fatigue
  • To optimize Dynamic Range, the higher/brighter the better, as long as don't loose detail in the highlights

D65

  • The standard point in perceptual color space used to define the standard for gray for HDTV video.
  • Your display will not accurately display the image if it does not closely match D65 when no color is present in the image
  • This is due to the way an image is created by painting colors on top of the base gray black & white image
  • D65 image is the color of the 'canvas' that your HDTV uses to display a picture
  • A quality display calibration must include verification that a display adheres to the D65 standard

DeltaE

  • A measurement used to indicate how much a color deviates from an accepted standard
  • The human eye is capable of detecting color difference at a threshold of about 3 DeltaE
  • Unless a display has a fully-realized color management system (CMS), it's unlikely that all the primary & secondary colors can achieve 3 DeltaE
  • Most displays will often meet the 3 DeltaE standard for gray scale which is critical for achieving the correct 'canvas'. (see D65 above)

Gamut

  • The 'color space' used by the display is smaller than the 'color splace' visible to the human eye
  • The bigger the color gamut the better

Gamma

  • Measure of how the image brightness changes with the input signal level
  • Proper Gamma is dependent upon environmental factors like amount of ambient light