Introduction to Color Management


Neil Schemenauer

neil@python.ca

Presentation Outline

  • Why do we need to worry?
  • Examples of limits
  • Extreme colors (sRGB, Adobe RGB)
  • Human vision limits
  • Hardware limits (cameras, displays, prints)
  • Printing problems
  • Camera settings, monitor calibration
  • Sharing and printing

Why do we need to worry?

  • Camera and display media cannot reproduce real scene as human eye sees it.
  • How to work within limits for best artistic effect?

B/W Example, full tonal range


Full 8-bit, 256 levels of grey going from full white to black.

B/W Example, clipped


  • Levels outside a middle range are clipped to full white or black
  • E.g. HDR scene captured with single exposure

B/W Example, low contrast


  • Full range of scene mapped to limited range
  • E.g. HDR scene captured with bracketing, etc.

B/W Example, reduced bit depth


E.g. limited bit depth in file format

Color range, sRGB vs Adobe RGB

Adobe RGB

sRGB

It goes one louder

  • How pure green is #10 green?
  • How big is step from #10 green to #9 green
  • How much more black could this be?
  • Could be more black if didn't use color management

Human vision and color, CIE color space

Credit: Paulschou @ Wikipedia

Color Spaces: eye, images, devices

Credit: Adobe

Color Spaces: sRGB, Adobe RGB

Credit: MBearnstein37 @ Wikipedia

My prints are too dark?

  • Monitor brightness set too high
  • Monitor not calibrated
  • Not using profile for printing process (ICC)

Camera setting: sRGB vs Adobe RGB

  • Set to sRGB unless you know otherwise
  • Use RAW to preserve quality
  • Export JPEGs as sRGB
  • Export as Adobe RGB only if needed
  • Internally Lightroom uses "Lightroom RGB" (96-bit)
  • Darktable uses LAB color (128-bit)
  • Both massively better than saving to JPEG (24-bit)

Monitor quality, settings, calibration

  • Desire monitor with wide color space (% of sRGB)
  • High contrast ratio (beware marketing speak)
  • Lower brightness from default (ISO 200, F6.3, 1/30 sec)
  • Target 100 Cd/m^2 (maximize contrast ratio of LCD)

Display calibration hardware

  • ColorMunki (i1Display Pro)
  • Spyder
  • Plug in, hold against screen
  • Make best use of limited monitor (can't make bad good)
  • Share with friends?
  • Ensure monitor matches printing process

Sharing Photos Online

  • Average user has high brightness, bright room
  • Assume they have sRGB, browser does not support Adobe RGB
  • Use full tone range
  • Instagram: bright photos have more "likes"

Soft-proofing

  • Feature of Lightroom or similar software.
  • Need display device profile (ICC)
  • Find problem before print is made
  • Not foolproof (e.g. display limited)

Conclusion

  • Brief introduction
  • Not an expert like Robert Ito
  • Reduce unknown unknowns