YRGBK 2.3

YRGBK is a Spot Color separation script for Adobe Photoshop. The YRGBK script  is designed for preparing color separations for screen printing on paper and textiles. YRGBK works in Adobe Photoshop CS3 through CC. English version only.
(please note, the scripts only work in English language versions of Adobe Photoshop)

Install
Find the read-me txt file in the download for complete installation instructions. The Script should be installed in Adobe Photoshop’s®  Scripts folder for best results. Copy the entire pspscripts folder, containing the YRGBK2.jsx file, to the applications scripts folder:
~ /Adobe Photoshop/presets/scripts

Settings
Before beginning it is best to configure Adobe Photoshop’s color settings. In the applications menu go to Edit/Color Settings. In the color settings menu set the working spaces RGB profile to Adobe RGB.

Set the Gray working space and the Spot working space to the same values. For screen printing on textiles a Dot Gain setting of 30% to 40% is recommended, depending on your materials. To set a value above 30%, select the  Spot or Gray drop down and choose Custom. In the window that opens, enter a value in the 50% box. For a Dot Gain of 35%, for example, set 50% to 85%.

Processing a file
Start with an Adobe Photoshop document, in RGB mode, containing a single layer on a transparent background. It is best, for generating a white highlight and Base white, if transparency surrounds the entire image. Merge all layers but do not flatten, and save this as a new document. In the Applications menu select:
File/Scripts/PSP YRGBK2

When the script is selected in the script menu a dialog will open displaying the scripts options.

The main window.
The YRGBK script options allow you to control how a separation is being generated, and how it is adjusted for printing. There are Three option groups in the main panel: Separation Options, More Options, and Dot Gain.

The Separation Options. The top left panel contains the three main options which display additional dialogs, as well as the basic adjustments which are the core of the script: Custom Black , Custom White and Custom Colors.

• Custom Black Check box – Displays the Black Generator options window.

• The Custom Black Slider determines how far into the colors the Black prints. The Higher the number the more black is generated.

• Custom White Check box – Displays the custom Highlight and Base White options window.

• The Custom White Slider determines how far into the colors the White prints. The Higher the number the more white is generated.
more info

• Custom Colors Check Box – Displays color density and adjustment options.

•  The Auto check box sets each colors darkest pixel value to 100%. The auto selection overrides the default color values.

• The Density slider increases the default density values of each color or the level of the auto selection. The Higher the value the greater the density of each color channel. The Auto and Density options adjust the black point of each color channel.

• The Saturation slider increases or decreases the middle value of each color channel. A setting of 50% makes no adjustment. The effect is to increase or decrease the overall saturation of the final separation.
more info

More Options
The top right panel contains additional options for generating the color separation. Options include generating a Gray channel, a Gray Component channel, Clean up and additional color adjustments.

• Gray Channel check box – Generates a gray channel within the separation and opens the Gray options dialog window. The Gray channel pixel values are removed from the Black channel.

• The Gray channel slider determines how far into the colors the Gray prints. Higher values increase the amount of Gray in the colors..

• Gray Component check box – Generates a Gray Component channel and opens the Gray options dialog. The Gray Component channel contains Black and Gray values lighter then a certain threshold. The Gray component threshold, or Gray Ramp, can be adjusted in the Gray options dialog. The Gray Component channel pixel values are removed from the Black channel. If The Gray check box is also selected, Gray values are removed from the Gray component channel.

• Cleanup – The Cleanup option removes stray values and generally removes problematic pixels. In some cases it is helpful to uncheck the Cleanup option and clean up the separation manually.

• Use Ink Colors – sets the color channels to printable color values within the Coated Spot Pantone color book range. Unchecked, the script will use primary color values.
more info

• Shadow Colors – Increases the density of the colors in the darkest areas.

•Highlight colors – Increases the density of the colors in the Lightest areas.

Dot Gain
The Bottom panel displays the dot gain option as well as the option to adjust the color settings while running the script.

• Use Gray Profile – Uses the Working Gray profile in the color settings dialog to adjust the channels for dot gain.

• Edit Color Settings – Opens the Color Settings dialog.

Advanced settings
By checking the Custom Black, Custom White, Custom Colors, Gray Channel or Gray Component boxes additional dialogs with the advanced settings will be displayed.

Custom Black
The Custom Black option allows changes to be made to how the Black channel is created. The left panel displays the Saturation Mask options and a brightness adjustment, while the right panel allows specific color adjustments and customization.

Saturation Mask – Where the Custom Black Slider in the Main menu determines how much masking is applied, the Saturation mask options determine how the mask is generated.

• Yellow/Green and Red/Blue – Adjusts the mask density in the corresponding color ranges. The higher the number, the more black is removed from the colors.

• Tint, Tone and Shadow – These sliders allow changes to be made to the masking in specific value ranges. These adjustments only affect the image where there is a hue. The higher the number the more black is reduced in the value range.

• Brightness – The Brightness adjustment reduces the amount of black printing in the shadows. This is a global adjustment and modifies the black in neutral values as well as hues.

Remove Black – The right panel options modify the amount of black printing into each color.

• The Color Sliders –  The colors sliders reduce the amount of black printing in the assigned color. The higher the number the more black is removed.

• Equalize – runs a script that balances the Black channel based on the values of the ink colors

•Show Dialog – displays the Adobe Photoshop dialogs available for the Black generator.

Gray Ramp and Gray Component – Determines the Gray values

• Gray Ramp slider – The Gray slider adjusts the amount of black which is handled by the Gray channel. Higher values increase the amount of gray generated.

• Gray Component slider – The Gray Component slider adjusts the amount of black which is handled by the Gray component channel. Higher values increase the amount of Gray Component generated.

Custom White – Highlight and Base White.
The Custom white dialogs allow the white highlight and the Base white to be customized.

White Generator- Highlight

• Highlight Curve – The Curve value sliders determine the value ranges printed by the Highlight white. The clip slider controls the cutoff value for the white, while the remaining sliders control the percentages.

• Customize Base – Opens the Base white options dialog

• Show Dialog – Displays the Adobe Photoshop dialogs available for the white generator.

• Remove Highlight – The color sliders allow the amount of highlight printing over each color to be reduced. While the Custom White slider in the Main menu controls the overall amount of white printing into the colors, these color sliders allow each colors white overprint to be customized.

White Generator – Base

• Base Curve – The Curve value sliders determine the value ranges printed by the base white. The clip slider controls the maximum value for the white, while the remaining sliders control the percentages.

• Choke – The Choke reduces the size of the Base white using the transparency of the original image. By choking the base white the separation allows the separation to completely cover the Base when printed. The Choke amount is in Pixels. For a 300 ppi image, a Choke of 1 pixel is sufficient for high tolerance printing.

• Show Dialog – Displays the Adobe Photoshop dialogs available for the Base White.

• Increase Underbase – The color sliders allow the Base white density to be increased under each color separately.

Custom Colors
The Color Generator provides options for changing the color adjustments and Color generation.

• Transition Mask – Controls the transition between colors

• Show Dialog – Displays the Adobe Photoshop dialogs available for the color Generator.

Color Levels
The Color levels adjustments determine the default density correction applied to each color channel. Where the Density adjustment in the main panel provides a global adjustment, the color sliders allow each color to be adjusted.

• Auto – The Auto check box overrides the Color levels adjustments in this panel.

• Midtone – determines the mid value of the density adjustment.

• The Color Sliders – Allow the density of each color to be adjusted separately. This controls the Levels adjustment to each channel.

Success – When the script has completed it will display the Success dialog. Checking the about box displays information about the script.

Color Separations for Screen Printing