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Colour Management - How It Works - Calibrating and Profiling Colour Monitors

Monitors can be calibrated and profiled to provide quite accurate "soft proofs". This only applies when the correct output (printer) profile has been selected in Photoshop's "Color Settings" and "Proof Setup" Menus however! In our experience less than 50% of Designers/Prepress companies have properly calibrated displays!

There are several excellent monitor profiling packages available. These are now very reasonably priced (under £200) and usually include both the hardware and software. The hardware is a small "puck", usually a colorimeter, which is placed against the screen and measures light and colour. These days the same kit usually measures both the older CRT (Cathode Ray Tubes) and newer LCD (Liquid Crystal Display) screens, but check before purchasing. Also check how many computers on site that the software is licensed for. Some more professional (and more expensive) software wil need an optional licence for each computer "seat". We can thoroughly recommend the X-Rite i1 Display 2 (formerly Gretag MacBeth). Please note: we don't sell these, but dealers can be found by searching the Internet. There are cheaper versions of this and other instruments, but we do not know of their suitability for high-end calibration.

Before commencing monitor calibration and profiling, you must check the monitor's basic settings. These are normally accessed via On Screen Display (OSD) software, using buttons on the monitor. The Apple Cinema Displays and iMacs don't have this facility (the software will instead download curves into the Graphics Card). Check the monitor's manual! Normally this menu is a bit fiddly! If there is an option to set Colour Temperature, also known as White Point, as it corresponds to the Colour Temperature used to view white paper in your Viewing Booth. It goes without saying that proofs should always be viewed in a Viewing Booth. Initially set this to 5000°K (K for Kelvin) or to D50. This is a starting point only. The monitor's Colour Temperature control will only be approximate.

You may well find that although 5000°K ("D50") is the industry standard for prepress viewing, 5500°- 6500°K may be more appropriate for your monitor. The best way to check that Colour Temperature matches that of your viewing booth is to create a "Canvas" of white paper in Photoshop using the correct "Color Settings" for your printing conditions. You then compare this image with that of a sheet of your normal high quality printing or proofing paper in the viewing booth. You should also display high quality images in Photoshop and prints/proofs of the same image in the booth. Pay particular attention to highlight detail and dark shadow areas. You may have to modify Brightness settings in the monitor's hardware.

The profiling software's manual or "wizard" will talk you through the other settings such as Brightness and Contrast.  Contrast is normally set to max (theoretically not used on LCDs).  Write down the numbers you use. You will also later need to set other monitors to the same settings. All these controls function by adjusting the actual monitor's internal hardware or sending curves to the Graphics (Video) card..

The software will also ask you to set Gamma. This can simply be regarded as the mid-tone density. 1.8 was the traditional starting point for Macs. Nowadays  many Mac users prefer 2.0 or 2.2. Some very professional software applications will use L* (Luminance curves).

The profiling software will display a series of colour patches on the monitor, while measuring these with the colorimeter puck. When measuring is complete it will generate a Monitor Profile which it will usually install in the correct place. You should also give it a recognisable name and date, such as "Bobs MacPro Monitor  20_03_08.icc".  It is also advisable to check that the new profile is now the default.  In Mac Os X this can be checked with "System Preferences/ Displays/ Color". If you don't have access to calibration kit you can do a very basic visual calibratio here. Some calibration software may place the profile in the individual user's account under  "Home/Library/ColorSync/Profiles folder". This is a complication of Os X, meaning each logged-in user may need a copy of the profile. In Mac Os9 it can be checked with "Control Panels/Monitors/Color". In Mac Os9 or below (or Windows), before profiling ensure that any "Adobe Gamma Control Panel" or similar, is NOT active. Also check that the resolution and refresh rate, etc. is the optimum. Another thing to check under System Preferences/Universal Access/Seeing/Display/ the "Enhance contrast" slider MUST be set to "Normal" before profiling or results will be very strange.

Note that on a Mac (as opposed to that other "operating system"), Monitor Profiles are NOT accessed from within Photoshop, unlike Printer Profiles. The profile will be available to all "ICC savvy" applications, while other applications )some browsers, etc.) will be have improved viewing resulting from the new calibration.  Also be aware that the excellent Apple Cinema Displays only have hardware Brightness settings, and no adjustment for Colour Temperature or Contrast. Be aware that the Brightness on these (and other brands) is usually factory set to a very high level. This not only gives unnatural results, but causes eye-strain, and perhaps strain on the wallet by reducing the life of the display! Also be careful to use the "Energy Saver" to turn off the Display when it is idle, which will also alleviate screen "burn-in" from continuously displayed windows, etc.

It may be advisable to use a Colour Management Consultant to  work with you and train you the first time you calibrate and profile your monitors. We have unrivalled expertise in Colour Management. To find out about our ICC Profiling services, please visit our  Home Page

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