Visual Development Lab

Lab McMaster

   Site map
McMaster logo


Map
People
Our Research
Publications
Nuts & Bolts

Computers

Colour

Every physical device produces a different set of colours. For this reason, no one device will be able to reproduce exactly the colours of another. To match colours (in theory) or to create pleasing approximations (in fact) requires:

  1. A map of all the colours that can be perceived by a normal observer (the CIE map of colour space).

  2. A standardized table of numbers representing every point in this map.

  3. For each device, a profile identifying:

    • the colours (by standardized number) that the device can produce and
    • the digital input needed to produce each of those colours.

    The profile for a device is usually supplied by the manufacturer but it assumes normalized viewing conditions. Since your conditions are likely to differ from these, it is sensible to create your own profile calibrated to your own work-space and lighting.
  4. A way to tell the computer to how to specify specific colour profiles for specific devices.

On a Macintosh, the software used to identify profiles with devices is called ColorSync. For every device there is a way to select a ColorSync profile. For printers this is in the pop-up menu in the Print dialog and for monitors it's in Displays under System Preferences (with old systems this may be called Monitors and be under Control Panels).

To calibrate a display for specific conditions, open Displays, choose Calibrate then Expert Mode and follow the instructions. At the end you will be able to save the profile so that you can select it again.

The calibration routine will have you balance a number of colours then choose a degree of contrast ("gamma") and the colour of white. The standard for gamma is 2.2 but 1.8 may be more comfortable in a well-lit office. A target white source of 6500˚ will usually produce the most pleasing colour.

For more information, see Colour & Computers.

News

Valid HTML 4.0!