1. Introduction


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iCorrect Portrait is a color correction filter plug-in for Adobe Photoshop and other popular imaging programs. The iCorrect Portrait plug-in makes global color corrections based on:

Many of the tools and much of the philosophy behind iCorrect Portrait are the result of the observation that almost everyone knows what certain colors should look like. When an image is viewed, it is surprising how easily color errors are seen, even by people untrained in this discipline. For example, everyone knows that snow is white (neutral) and what skin should look like. If an image shows a person's face that is bright red, the observer knows that the color is wrong, even though he may never have seen the actual person in the image. These common reference or "memory" colors form the basis of iCorrect Portrait's approach to improving the color of an image.

In many production environments, color management, using ICC device profiles, is rapidly becoming the preferred method of producing color-accurate digital images. While this may be the best way to control color reproduction in many situations, it isn't always possible. There are large classes of digital images of unknown pedigree. It is not possible to use device profiles to relate the colors in these images to any device-independent reference because the profiles do not exist and cannot be made after the fact. For example, you may not have any information about how images on a stock photography CD-ROM were acquired. iCorrect Portrait can be used to quickly and easily correct uncalibrated images such as these, transforming them into a calibrated color space.


Very Important Photoshop Setup Information!

iCorrect Portrait will always correct the color of an image to Photoshop's currently selected RGB working space. Therefore, it is critical that you have Photoshop set up in a way that allows iCorrect Portrait to perform properly. Here is a checklist:

  1. Calibrate your monitor and load its profile as the system profile.
    The manner in which you do this depends on both the platform you are on and the operating system version you are running. Your monitor profile affects the way in which colors are displayed in Photoshop, and also in iCorrect Portrait. If your monitor profile is bad, colors will not look right.

  2. Select a "normal" RGB working space in Photoshop.
    Normal working spaces are theoretical in nature and have certain "nice" properties, for example, a neutral color by definition has its red, green and blues values equal to each other.

  3. Never select your monitor profile as your RGB working space.
    Monitor profiles generally do not have the "nice" properties discussed above that theoretical working spaces should have. Incidentally, Adobe also recommends against using your monitor profile as a working space.

  4. If your image has an embedded profile, convert it to the working space before using iCorrect Portrait.
    This may be done when the image is first opened, or it may be done with Photoshop's "Convert to Profile…" command.

  5. If your image has no embedded profile, assign the working space profile before using iCorrect Portrait.
    This may be done when the image is first opened, or it may be done with Photoshop's "Assign Profile…" command.

Photoshop's working space is selected with its "Color Settings" dialog for versions 6 and later, or with the "Color Settings / RGB Setup" dialog box with version 5 (also check the "Display Using Monitor Compensation" checkbox). If you are running an even earlier version of Photoshop, be sure that the settings in the Monitor Setup dialog box accurately describe your monitor.

Once you are properly set up, iCorrect Portrait will correct your image to Photoshop's working color space (Photoshop 5.0 and later) or to the color space defined by the Monitor Setup parameters (Photoshop version 4 and earlier).

Here is a suggested Color Settings set up that will help make sure your image properly ends up in the working space (shown for Photoshop CS2):

If you are using the plug-in with an application other than Photoshop, you should be aware that not all applications provide the same color management setup information that Photoshop provides. If iCorrect Portrait cannot get this information about color settings from your application, it will correct the image into

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