Adobe 65008009 - After Effects CS4 Technical Paper page 26

About color profiles
Precise, consistent color management requires accurate ICC profiles. For example, without an
accurate profile for video footage or motion picture film stocks, an image may appear correct
in one application and incorrect in another application, simply due to any difference between
the color characteristics of the capture medium and the assumptions made by the application
displaying the image. This misleading representation may cause you to make unnecessary, time-
wasting, and potentially damaging "corrections" to an already satisfactory image. With an
accurate profile, an application importing the image can correct for any device differences and
display an image's correct colors.
A color management system uses the following kinds of profiles:
Monitor profiles
• — Describe how the monitor is currently reproducing color. This
is the first profile you should create, because it is critical for accurate display of color
on your computer monitor. If what you see on your monitor is not representative of
the actual colors in your document, you will not be able make critical color decisions
when editing your project files.
• Input device profiles — Describe what colors an input device is capable of capturing.
Adobe supplies many input profiles representing the color characteristics of several
types of video cameras, as well as profiles for popular camera negative film stocks.
Scanner profiles are also examples of input profiles you can use in your workflow.
Output device profiles
• — Describe the color space of output devices like digital
cinema projectors and desktop printers. The color management system uses output
device profiles to properly map the colors in a project to the colors within the gamut
of an output device's color space.
Project working space profiles
•
project for compositing. By specifying a profile as a project working space, the appli-
cation provides a definition of actual color appearances in the project.
Scene & presentation environment profiles
Adobe provides a wide range of ICC profiles for motion picture and video workflows. Many
of these profiles represent the color and lighting characteristics of scenes when captured using
digital or film cameras. Other profiles represent the color and lighting characteristics of images
seen when viewed in environments with much more limited dynamic range, like movie theaters
or computer monitors. For instance, a typical dynamic range of a scene viewed outside during
the day in natural light could be 10,000:1. However, a scene viewed on a television or computer
monitor may have a dynamic range of only 100:1. An understanding of the dynamic range
a device "sees" or renders is incorporated into the ICC profiles built for those devices. As an
example, the video camera profiles provided by Adobe are based on the range of colors and tones
available in those scenes when those scenes are captured by the camera. The range of luminance
in those scenes is much greater then that rendered by movie projectors or television monitors.
How does this apply to a color-managed workflow in After Effects? Because "scene" profiles con-
tain an understanding of the scene contrast as recorded by the camera, they are best suited to use
for composing. This is the case for the HD video workflow, described in Chapter 2, which uses
a color depth of 16 bpc. The limited contrast of the "scene" profiles allow for more naturalistic
blending and compositing.
In the HD TV and digital cinema workflows, you may have cases where there is a mismatch
between the image state (scene/camera vs. presentation/display profile) of the footage that you are
importing into your project and your project working space. This may cause unexpected contrast
and tone changes to your footage when output. Imported images represented by the presentation
profiles (e.g., sRGB IEC 61966-2.1) have already been rendered from the contrast of the original
scene captured by the camera. When these images are rendered again during playback on an
HD monitor (or theater projection system for the digital cinema workflow), images will appear
darker.
New projects created with After Effects CS4 will automatically compensate for differences in the
image state of your footage, project working space, and rendered output. This is controlled using
the Compensate For Scene-referred Profiles option in the Project Settings dialog box. In most
— Define the specific RGB color space used in your
Color management workflow in Adobe After Effects CS4 26