Adjusting Colors

The Adjust Colors option in the YRGBK script provides a quick way to customize colors in a separation as they are created. In this video I am selecting the Adjust Colors option along with Show dialogs.

For colorful, saturated images screen printed on textiles this is a good approach. Selecting the Show Dialogs option allows access to the Levels as they are applied to each channel. Each color is set to print 100% black in it’s darkest values by sliding the black slider all the way to the first values in the Histogram.

Middle values
In this video I also reduced the saturation value in the script to 5. This compensated for the overall increase in density by shifting the middle, or Gray slider in Levels. I could have also used the Curves option for more control over the middle values. The Curves do not make any adjustments by default.

Customize the White

One of the key features of the color separation script is the Custom White generator. A repeatable white is a big help when designing color separations, and once you get a setting that works for you they rarely need adjustment. The white generator uses both a Curve to adjust the values, and a Saturation Mask to control the overprinting of the Highlight White. In addition there is a set of custom color adjustments which can be used to reduce the white overprinting.

In this video I use the custom adjustments to reduce the amount of highlight printing into the Green and the Yellow. The same adjustments are also available in the Custom White script.

YRGBK as a color mode

The best comparison I can make for the channels generated by the YRGBK script is to look at the color set as a kind of color mode, or color model. Like CMYK, the colors can be printed if you have decent control over the variables. With a few adjustments the color channels can be used to create custom color separations.

In this video I am using the script to begin a custom color separation in Adobe Photoshop® CC. I check the Custom black, Gray and the Color Settings options. This generates a gray channel and displays the Black options and the Color Settings preferences.

The color settings handles both the dot gain preview for spot colors, and the dot gain adjustment used in the color conversion.  The dot gain for this print is almost 40%, so I am using the Custom Dot Gain option.

At the end you can see the results of the script. The image used is from the original Photoshop document at 300 ppi, which shows in the quality of the channels.

YRGBK Options

It’s been a busy week here reorganizing, updating and adding new projects. I still have a way to go, so I hope you will stay tuned. Here is another quick video of YRGBK in action.

The YRGBK color separator is set up to run using basic default settings. Just click Ok.  For many images this is great, for others the options can be changed. YRGBK has additional option panels for creating custom black, custom whites and adjusting colors. This video shows all three option panels plus the main panel.

With an image like this I could re-run the script and make adjustments to the black setting and adjust the color setting. Often it is possible to merely adjust the channels to balance the image after processing, but in this case there might be some values dropping out. The resulting document contains the original RGB channels, making it easy to repeat the color separation process or run other scripts.


I am very excited to share the all new YRGBK color separation script for Adobe Photoshop® CS3 – CC.
Like the original, the new YRGBK script converts RGB images into multi-channel images for screen printing.
Check out the video…

It’s been a long year and I have been hard at it developing these color separation concepts, and I think they are ready. The new YRGBK script goes beyond my expectations, and really stands on its own as a professional color separation tool. I put a lot of work into the black and white generators with tons of improvements. With a new approach to dot gain and a new color system you can really see the difference.

In the video above you can see the YRGBK script run straight through, in real time on a medium sized image, in Adobe Photoshop CC. This particular image shows how well the subtle transitions are handled. In the coming weeks I will post more on the advanced features and how to use them to adjust for different images and substrates.

Read more here

I want to thank everyone for their support and especially for downloading. You make it happen.

The new SimRip

I am happy to announce a new version of SimRip. Check out the video.

SimRip is all new and improved. Convert any multi-channel or CMYK document to high resolution printable halftones within Adobe Photoshop®. The code has been streamlined for  faster processing. SimRip now works from any open or closed document. Enter angle and dot size settings in a single dialog for all channels. Output resolution and transfer function too.

Quick SimRip video

(Update: this is the previous version of SimRip. Please see the new version above.)

In this video I start with a ready to print color separation. You can see the channels in the top left. First, I close the separation I am about to rip, and load the SimRip script from the Scripts menu. I am presented with an options window, and choose the options I prefer. Next, I am prompted for the document to rip, and select it in the Open window.
The script makes a copy of the file and processes the channels.

Creating a printable color set from the YRGBK script pt 1

(Edit: this post discusses the previous versions of YRGBK.)

The first steps to making a printable color set from the YRGBK color set are to set the black point of each color channel, then adjust for dot gain. In the first, we are making sure that the darkest pixels representing each color are printing at 100%. The second step is to adjust for gain in the printing process.

The concepts apply to custom color separation in general, regardless of how the colors are generated. The YRGBK script merely provides a pretty good head start.

Black point, Dynamic Range, and Ink Coverage
 By setting the darkest value to 100%, we increase the total printable range of each color channel. In addition to increasing the range of values we can represent, setting the black points also ensures good ink coverage in colorful areas of an image. This in turn reduces the amount of pressure needed to get a  good print through a screen, improving both detail and dynamic range on press.

To set the Black point, select a spot color channel
• From the menu choose: Image/Adjustments/Levels
• Move the Black slider to the first set of pixels in the histogram

Dot Gain
With the Black point set, the next step is to adjust for dot gain in the color channel. By applying a curve to reduce the density in the mid range, we can compensate for the gain that occurs on press. A standard adjustment is generally required, although making a custom adjustment for the particular image is best.
(Before making a dot gain adjustment, be sure to set the spot color setting, in the color settings menu, to the correct dot gain for your print setup. This setting modifies the spot color channel preview when more then one color channel is visible.)

To adjust for dot gain:
• Select a spot color channel
• Open Curves from the menu: Image/Adjustment/Curves
• Click on the center (50%) of the diagonal line and move it down to the 30% range.
• This adjustment can be customized to suit the image, spot color, and black point setting.

Setting a custom color
Increasing the value of a channel increases the amount of color printed. The color of a spot color channel should also be considered when setting the pixel density. Using a less saturated, printable ink color compensates for an increase in color density.

• The Use ink colors option in the YRGBK script sets the color channels to printable ink colors.


Color Separations for Screen Printing