Colors and Color Lists

In the world of color reproduction, color lists are files used to describe a target to be measured, or the results of a measurement, sets of color pallets, and much more. Typically device settings (RGB, CMYK, and so forth) are compared with CIE color readings (XYZ, Lab, etc) to describe a list of colors and often to create an ICC profile. In most profiling applications, these color lists can be exported for use within ColorThink. ColorThink has powerful tools to enable color lists to be extracted, combined, subtracted and filtered in many ways.

Color lists can contain a mixture of device (RGB, CMYK, etc), Colorimetric (Lab, XYZ, etc) and spectral data.

Example of a color list

For a very simple example color list that can be read by ColorThink, see example of a color list in the documentation for the Grapher.

Opening Color Lists

• Select “File Open” and choose a text-based color list or

• Drag a color list onto the menu bar or

• Export a list of colors from a Named Color Profile (NCP) in the Profile Inspector.

ColorThink will display the color list in the Colors region of the worksheet. If the list file contained sample numbers and names they will be displayed also.

For colors that contain colorimetric (Lab, XYZ, etc) or spectral values, ColorThink will calculate a color patch for accurate display in the list (within monitor gamut limitations).

Saving Color Lists

To save a color list to disk, click on the list popup name above the list (it might be named “untitled” if it is a newly-created color list), and select Save List As...

A dialog provides options for which of the transform’s data sets should be saved in the file and the preferred units. ColorThink will save the list data to disk as a CGATS-format text file, a .cxf file, or an .mxf file (for use within i1Profiler).

ColorThink can view and save files in the following colorimetric color models:

• Lab, Jab, OKLab, WLab, LCH, Luv, XYZ, Yxy

Graphing Color Lists

Clicking on Graph List will send the points of the color list to the grapher and open the grapher for viewing.

Specific points in the color list can be highlighted using common conventions:

• Click + Shift to select a range

• Click + Control to select individual points (Windows)

• Click + Apple to select individual points (Mac)

Highlighted points in the color list will be displayed in the grapher with cross hairs to identify their position.

NEW!

List Joining and Filtering

Map list white point

Using the SCCA method (Substrate Corrected Color Aims), the values in the color list can be recalculated with a different white point. Enter the desired white point using Lab values, separated by commas.

Reorder List using current sort

The Worksheet column headings can be clicked on and ordered from lowest to highest, or highest to lowest. For example, you can click the “L” column heading two times and the Worksheet will rearrange all the patches to have the color list ordered from the highest “L*” value (at the top of the list) to the lowest. This changes the color list arrangement on screen, but does not affect the image area, and will not change the order of patches when saved out.

Reorder List using the current sort will apply that change in the color list so that the image area reflects the change, and the underlying color list will be changed. This way you can save out the new color list with a different arrangement of the same patches.

Reorder List using…

Similar to Reorder List using current sort, this Reorder List using… option allows you to choose a separate file with a different ordering of device values which will be used to determine the order of this file. For example, if you have a scrambled measurement of an IT8.7/5 chart, and you wish to see what the measurement would look like in the visual layout (unscrambled), choose Reorder List using… and pick an unscrambled target reference file. ColorThink will rearrange the target according to the layout of the second file. Note that this function works with the device values present in the files (for example: RGB, or CMYK values). It will not reorder color lists according to Lab values or spectral values.

Append to List…

Add to the existing color list by selecting another color list (must be in the same color space as original).

Subtract from List using…

Remove data that intersects. Remove colors from the existing color list that also are present in the second list.

Select from List using…

Only keep colors that are common. Remove any colors that are not present in both the original and the selected color list.

Remove duplicates

Filter out any duplicates from both lists so that the resulting file has no duplicate colors.

NEW!

Tune device values

This feature will make use of a profile to fine-tune the device values as close as possible according to a profile. A transform between two profiles in the Worksheet is required for this function to become available. This feature changes the device values to

The user can set the minimum device value, and the total ink limit imposed on the data.

NEW!

Color list tools

Color lists can be converted and displayed using many industry color values.

Options include:

Total Area Ink Coverage

This button will open a column calculating the total area of ink coverage for each entry in the list. (Not relevant for RGB color lists.)

Report

This button will calculate a delta E report (when delta E button is active).

Converting Between Images and Color Lists

ColorThink blurs the difference between images and color lists. Images can be displayed as lists of colors and color lists are displayed as images in the ‘Images’ region.

ColorThink can also explicitly convert from one data type to another:

• 

  Select Convert All Colors to List from the image popup menu. (This will convert every pixel in the image into a entry on a color list.)

• Select Extract Unique Color Values. (This will extract only the colors that are unique and place them in a color list.)

• Select Extract Unique Device Values

• Use the Target Marquee to select specific colors in a target layout

To convert an image into a color list

Do one of the following:

See the section Working with Images for more information.

A color list is created in the "Colors" section. The number, name and color information will be filled out automatically. The "name" column in a list of unique colors will be a number representing the number of times that color appears in the image. The name column in a list of colors made using the target marquee represents the x/y coordinates where that color appears in the image.

We also recommend clicking the new (untitled) color list and selecting "Use as primary data source" from the list popup menu. This will help make the list properly available to other transformations in the workflow.

To convert a list to an image

Lists are automatically displayed as images when the Image region is shown.

Choose Save Image As... from the image popup menu to save the image to disk.