Page 120 - Graphic Design and Print Production Fundamentals

108 Chapter 4. Colour Management in the Graphic Technologies
all users of the computer, while the user location will restrict it to the current user. Depending on your
permissions at the computer, you may not be able to write into the system location. On an Apple OS
X machine, the default location for the system is System/Library/ColorSync/Profiles and for the user,
Users/(userID)/Library/ColorSync/Profiles.

Viewing Your Profile

The Mac provides a built-in tool for viewing a profile or comparing two profiles. From the Utilities
folder, launch ColorSync. Select the second tab from the left and you’ll see a selection window on the
left and a display pane on the right. The selection window contains a list of all ColorSync aware locations
on your computer. Tip open the available folders and browse to find the profile you wish to view. Select
a profile and a three-dimensional representation of its gamut in the Lab colour space appears on the
right. Use your cursor to rotate the profile through all three of its axes. From the drop-down triangle in
the display pane, choose Hold for comparison. The current profile is ghosted back, and you can select a
second profile to display at full strength on top of it so you can compare the relative gamuts of the two
profiles.

Profile Limitations

Remember that your profile represents the behaviour of the device for particular imaging parameters
such as a specific substrate, resolution (screen ruling), and ink set. If any of those parameters are
significantly altered, it requires a new profile to accurately represent the colour results. For real-
world applications, profiles representing related groups of parameters are employed. One profile might
represent all uncoated stock at 100 to 133 lines per inch, a second for coated stock at 150 to 175 lines per
inch, and a third for a high saturation ink set on glossy stock with high resolution stochastic screening.

Media Attributions

• what is a profile by IFCAR adapted by Ken Jeffrey