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A very powerful feature of iCorrect Portrait is its ability to accept and use custom memory color definitions.
Each memory color is defined by three parameters that specify the way that you want that color to look after correction:
When you click on the Modify/Add Colors... button, some new controls will be displayed. In this section we'll learn about different ways to use those controls:
Creating New Memory Color Definitions
The custom memory color pop-up menu can contain up to eight color definitions, allowing you to create definitions that are important to you in general, or even for a particular project. Some good examples might be the creation of memory color definitions for your backdrops, a team uniform color, or for sky or foliage.
Begin by selecting the Custom memory color button. Then select an empty location from the Memory Colors pop-up menu. (If you haven't defined any custom colors yet, this will be done for you.) A new color will be created, with a default name and definition. The shaded color scale that appears below the menu shows the different tones of this memory color definition, from dark to light.
Begin by editing the Name field (only the first 19 characters are used):
From here, the color parameters for the definition may be arrived at by any of several means, as discussed below.
You can use the three interactive "handles" to modify the default color definition to come up with the desired color:
We will call these handles the Hue handle, the handle and the Chroma handle. The line that is drawn on the colored area shows those colors that are part of the desired color definition of this memory color:
Tip: In the discussions below, we will learn about adjusting these three handles. Normally, you will not see the visual effect of a change until you release the mouse button after moving a slider. However, if you hold down the key while moving any of these handles, you will get immediate visual feedback, before the mouse button is released. There is a substantial amount of computation needed to do this, so you may find the response to be too sluggish for your liking.
• Chroma Adjustment
The maximum saturation of the memory color definition is controlled by moving the Chroma handle to the right to increase, or to the left to decrease the chroma:
• Hue Adjustment
Similarly, the base hue of the memory color may be adjusted by moving the Hue handle to the left or right (remember that the Hue handle is the small square that appears in the center of the colored panel):
After releasing the Hue handle, the entire entire hue panel (the handle and the colors behind it) is scrolled so that the Hue handle is once again centered. This allows you to move it a second or third time if necessary, to reach the hue that you want (not all hues are shown at once).
• Adjustment
The handle is used to control the slope of the line:
When this line is vertical, then all shades of the memory color will be given the same hue. By tilting this line one direction or the other, you may give lighter and darker tones of this color slightly different hues. For example, our studies have shown that foliage is typically more yellow in light greens and more cyan in dark greens. That type of hue shift is specified by using a value for of -5 (that is, non-zero).
Tip: You may find it easier or more convenient to control the handles with the keyboard instead of the mouse. To do this, click one of the radio buttons to indicate which of the parameters you wish to control. Then you may use the right and left arrow keys to increase or decrease the value of the corresponding handle.
Depending on the situation, there are other ways to create memory colors that might be easier, quicker or more accurate.
Selecting from the Preview Image
One of the easiest methods of creating a memory color is also one of the most useful. In an application such as school portait photography, you may have a set of portraits that were all taken against the same background, but show differences in the background from one image to the next. You can open the image that you like the best, select the iCorrect Portrait plug-in, and click the Modify/Add Colors... button. Select the memory color from the pop-up that you want to define as the background color. Then just click on the background of the preview image. You can take up to five samples this way, and each will contribute to the memory color definition. It usually isn't necessary to make many samples though, since each time you click, similiar colors in adjoining areas of the image are also sampled. A new memory color will be created, based on your favorite background, which can then be used to correct the backgrounds in the other images.
Using the Color Picker
If you click the "Picker…" button, a color picker will appear which you may use to select a color:
Note that the appearance of the color picker will depend on your choice for Color Picker in Photoshop's General Preferences. iCorrect Portrait will analyze the color you picked and from it, produce the necessary color definition parameters. You may further modify these settings if you wish, in the manner described earlier.
Importing a Color Measurement File
This is strictly for advanced users. It requires access to a colorimeter or spectrophotometer.
If you have access to a colorimeter or spectrophotometer, you may measure samples of a desired color, enter these measurements into a text file and then import the text file into iCorrect Portrait.
The text file may be created with any word processor capable of saving a plain, unformatted text (ASCII) file. Your measuring instrument may also be able to save its measurements as a text file. The format of this text file is described here.
The first line of the file must contain a keyword indicating the type of color measurements contained in the file. This keyword must be one of the following:
These keywords are case sensitive, and must not contain any extra characters on the line, such as "space" characters. The remainder of the file will contain the color measurements, one color measurement per line, and of the form indicated by the keyword. Please note that all measurements must be made relative to the CIE D50 reference white and the CIE 2° standard observer. In addition, the three components of each color measurement must be separated from each other by one or more spaces or tabs. Here is an example of a measurement file containing three CIELAB measurements:
Lab
73.12 12.34 -8.98
55.80 21.19 -17.34
29.11 15.78 -10.65
An error will be reported if this file format is not followed.
To use this measurement file in iCorrect Portrait, click the Import… button and then select the text file.
iCorrect Portrait will analyze the color measurements and find the best color definition parameters for it.
The name of the measurement file is used to name the memory color, but as always, you may change the name if you wish.
Modifying Memory Color Definitions
You can modify any of your previously defined memory colors, as well as the two built-in memory colors, Neutrals and Skin. Just select the color you want to modify and then use the tools as described above.
Tip: If you made any color corrections using this particular memory color before entering the Memory Color definition panel, you will see the effect of the memory color definition adjustment in the image preview pane. This may help you decide what adjustments are most appropriate.
Restoring Memory Color Definitions
If you have modified the Neutral or Skin definition, you can restore the built-in factory default definition by clicking the Neutral or Skin button and then clicking the Restore button:
Saving and Loading Memory Color Definitions
You can save any memory color definition to a file by clicking the Save… button:
Click the Load… button to read a memory color definition from one of these files:
The currently selected memory color will be replaced with the one read from the file.
The Save and Load features allow you to manage larger sets of memory colors, for example if you have different definitions made for different jobs.
Deleting a Memory Color Definition
To remove a custom memory color definition that you no longer need, select it from the pop-up menu and then click the Clear button:
The name and definition will be removed, and the corresponding item in the pop-up menu will also be cleared. You normally wouldn't want to remove a color that you are using to correct an image, but if you had already used the color to make color correction marks in your image, those marks will be removed when you clear the color. Note that the Clear button does not appear when the built-in Neutral or Skin tone definition is selected, so it is impossible to remove the two built-in colors.
When you have adjusted the memory color definitions to your liking, clicking the "Save" button at the bottom of the panel will cause iCorrect Portrait to use the new definitions for color correction in the main iCorrect Portrait window. Clicking the Cancel button will restore the original parameters (all memory color settings) to the values they had when the Memory Color definition window was entered.
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