Customizing a Color Separation generated using YRGBK2.3

YRGBK2.3 creates a simulated process style color separation which uses bright, saturated colors along with Black and White. The separation is easily adapted to using custom colors.

5 Steps for customizing a color separation

Run the YRGBK Script

Start by making a color separation from an RGB image using the YRGBK 2.3  script.

1. Discard, Merge and Split Channels:

– Since not all images will require all the colors, we can discard any channels with no color data.

– Merge Channels: Colors can be merged into other colors in order to reduce the number of colors needed.

 – Split Channels: Colors can be split into separate spot colors using masks. Separating text from halftones, dark colors from light colors, or bright colors from dull colors.

2. Set Custom Colors:

The Spot color Channels can be modified to use colors specific to the image.

To set a Color Channels spot color values to a custom color.
(*Both documents must be in the working RGB mode to load the correct color)

  a. Open a copy of the RGB file for the image next to the open color separation.

  b. In the color separation document, double click on a spot color channel to see its options.
  – Click on the color  box to open the color picker.

  c. Click on the most colorful area of the color you are choosing in the RGB document to select the color.
  – Click OK in the color picker and spot color options.

3. Adjust Density and Saturation:

The density of the channels can be adjusted to accommodate custom colors and different substrates.

See also: 
Setting the Black and White Points
Saturation and Density

To set a Color Channels Density for creating custom colors.
1. Select the color channel and open the Levels or Curves dialog.

2. Slide the Black point to the first set of pixels represented by the histogram. This is easier to see in Levels, where the Black point is the black triangle under the graph, while the pixels are represented by the vertical lines in the graph.

Notice how this step works with the previous step to bring the amount of color in the image back to a normal level. If the correct colors are selected, the image should bounce back to the proper saturation.

4. Color corrections and distribution

Global corrections to an images color balance can be made after making Density and Saturation adjustments. Specific corrections can be made using using color range selections or color channel  selections. Careful attention to ink densities and total ink deposits is required.

5. Adjust the Black and White:

In a simulated process color separation, the Brightness of an image is handled by the Black and White channels. When custom colors are used in the spot color channels, the Black and White should be adjusted to compensate for the new colors brightness.

To adjust the Black (or White) channel for custom colors.

1. Load the color channel into a selection, either by cmnd/cntrl clicking the channel, or by selecting Load from the selections menu.

2. Select the Black channel and open the Curves dialog.

3. Slide the White point to the value where the black should be 0%. ie: The value of the Black where the color channel being used as a mask is 100%. (This number can be found by measuring with the curves dialog open.)

Use the same steps for the highlight white channel.


  See also:
Tools and Techniques PDF

Much of what you will want to do to a color separation depends on what you want to do with it. The type of ink, the substrate, and the printing process all determine what modifications are needed for a good print.

Happy Printing

Color Separations for Screen Printing