Tuesday, October 2, 2007

More Colour Management

When we left off, we were talking about managing colour throughout the entire suite using Adobe's Bridge. Again, the great thing about setting up colour management in Bridge is that colour settings are automatically synchronized across all the Creative Suite programs. From a workflow standpoint, its always a good idea to configure the colour settings before you begin to work with your equipment on casework. If you haven't already performed theses steps, its best to do so now. 

To review, in order to manage colour with Bridge, you need to enable it as a function:
Edit>Preferences>Advanced>Enable Color Management in Bridge (check box)>OK.

Let's look at some of the common terms that you'll see in some of the colour management settings*.

Working Spaces: Defines the working colour profiles for each colour model.

Color Management Policies: Defines how the colors in a colour model are managed. Choose to embed or convert the selected profile ... or just ignore it.

Conversion Options: Defines exactly how you want the conversion process handled. Using a colour-defined Engine and colour conversion Intent.

Advanced Controls: Desaturate Monitor Colours gives you the ability to control the viewing of a colour space on different monitors but if you activate it your images will print differently than viewed on your monitor.

Rendering intents deal with how a colour profile is converted from one colour space into another. In specifying a rendering intent you are saying how you want the colours to be displayed (Click on the title link for a great explanation and graphs on Rendering Intents). This can cause issues if your target gamut does not have enough space for all of the colours in your image. Some of this problem can be solved moving your image to a large gamut space like ProPhoto RGB and converting the image to 16bpc

Here are your options:

Perceptual. Preserves the natural colours of an image, as viewed by the human eye, sometimes at the expense of the true colour values.

Saturation. Creates vivid colours in an image, with little consideration given to the original colour values of the image.

Relative Colorimetric. Shifts the colour space of the document to that of the maximum highlight values of the destination. Preserves more of the original colour than Perceptual and may be the best choice for moving from your source space to ProPhoto RGB. As with everything in the forensic world, test your theories on your own equipment and be able to explain what you did - in case you are questioned later in court (forensics).

Absolute Colorimetric. Clips any colours in the destination image that do not fall into the colour gamut of the destination.

Another great resource for this discussion is Bruce Lindbloom's web site.

*The Photoshop help files are a great resource for further reading. 

In the next installment, we'll look at some starting tasks that we can automate before we begin to process our images.

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