Yrgbk 2.3 – The Custom Black, White and Gray sliders
In the YRGBK 2.3 script, the Black, White and Gray sliders control the amount of Black, White and Gray ink printing into the colors. The effect is to brighten the image by letting the colors show through. The level of brightness is controlled by the sliders; higher values in the slider increase the amount of ink, while lower numbers decrease the ink levels. Controlling the amount of Black in an image’s colors is useful for images that are either brightly colored or contain a lot of detail.
The Saturation Mask
The adjustment applies only areas of color. The Script generates a mask using the saturation values in the image. The greater the intensity of the colors, the heavier the Saturation Mask will be. Detailed adjustments can be made in the Custom Black dialog, using the Saturation Mask settings, by checking the Custom Black Checkbox.
Using the Black, white and gray sliders
if I need more detail in my colors, or if my colors are highly saturated, I can increase the value in the slider. if I need less, say for instance I have an image with pure solid colors and a black line, I can decrease the black slider to clear the black out of the colors.
The default settings are balanced with the colors assigned to the color channels.
The Use Ink colors option does just what it sounds like, sets the final channel colors to printable ink color values. By unchecking the Use Ink Colors check box we can display a wider gamut of colors, but they will be outside our printable color range.
The YRGBK script splits the colors in an image into Hues and the Values, with all of the Value information going to the Black, White and Gray channels. The Hues are then split into a set of primary colors, and, if the Use Ink Colors box is checked, assigned printable ink colors. The Black channel is adjusted automatically to work with the colors.
When a color in an image falls outside of the color range generated by a color model the color is said to be “Out of Gamut”. The YRGBK script generates a color model whose Gamut is limited by the ink colors used. Colors which can not be created by the inks are printed using the closest color available. By Unchecking the Use Ink Colors check box we can keep the colors in their original, primary state, generating a separation with a much larger color range.
If, when running a separation through the script you notice a large color shift, it can be helpful to turn Use Ink Colors Off to visualize the whole color gamut.
To generate a Primary color separation: • Uncheck the Use Ink Colors checkbox in the main window • Check the Custom Black box • Check the Custom Colors box
Adjust the Black Values
In addition to setting the color values, the YRGBK script makes adjustments to the Black channel to accommodate the brightness of the ink colors. When Unchecking the Use Ink Colors option, there will not be enough Black generated to render the image fully using the default settings. To fix this:
• Set the custom Black slider in the main window to 100. • In the secondary Black Generator window, set both the Midtone and Shadow values to 0.
Adjust the Saturation Levels
Color channels are also adjusted for Saturation levels by the script. The Colors in the primary set have a saturation of 100%. Ink colors, on the other hand, have much lower saturation values based on the selected inks.
For most images the default settings are calibrated to generate good results using the Ink colors. For some images we need to adjust the density of the channels to achieve proper saturation levels. The Color levels sliders in the Color Generator dialog adjusts each channels density individually. To reset the color adjustments for a primary color separation:
• In the Main window, set the Color Density to 0 • In the secondary Color Generator window, set all the color sliders to 0, the Midtone to 100, and uncheck the Transition Mask box.
The Use Ink Colors option is checked by default, and in most cases this is where you will want to leave it. This setting will automatically bring your colors into a printable range that works with the default settings in the rest of the script. Often it is easier to customize the color channels after running the script then it is to run a primary color separation and make it printable. A primary color separation generated in this way would need to be manually adjusted to achieve printable results.
That said, in the case where you have large color shifts, unchecking the Use Ink Color dialog can quickly create a wide gamut, fully saturated color separation. Creating a primary color separation in this way can help to visualize a solution, or can be used as a starting point for working the separation up manually.
The Original The Custom Black script is designed to generate a Black, Light Black and Gray channel as needed. I had found that in my work I occasionally required just a Black or a Gray channel, and that instead of running the full color separation script it would be nice to have a script tailored just for this. And so was born the Custom Black, as well as it’s partner the Custom White.
The New Part of the overhaul of the YRGBK script was a refresh of the Black module. While the core approach remains the same, I spent a lot of time looking at how the interface is used, as well as how to improve the techniques and quality of the channels. The result was a much improved Black generator with better options and usability. The Custom Black script uses the same Black module as the new YRGBK script, with a few additions for generating the channels mid-separation.
The Main Window The first window in the script provides sliders for controlling how much color masking is applied overall to both the Black and the Gray. Most adjustments for a particular type of color separation or set up can be done with these sliders. Bright images with primary colors and key lines can use a black that is turned way down, while photographic images will work best with the default settings. The slider range is now 0% to 100%, with higher values printing more Black into the colors.
In addition to these sliders, you can open open more advanced dialogs as well as generate a Gray, the Gray Component and a Mask channel from the main window.
The Black generator and the new Saturation Mask Options In the secondary window for the Black generator I added more options to control how the Mask is generated and applied. This finer tuned control improves both the results of the script as well as its flexibility. With the addition of Tint, Tone and Shadow sliders, the amount of black printing into the colors can be adjusted for different value ranges, while the color sliders allow adjustments for particular colors.
The Saturation Mask revisited The main component of the Black generator is the mask that limits the amount of black printing into the colors. This is called the Saturation Mask, as it is derived from the color saturation of the image. Starting with the images Luminosity, the mask is applied along with a gain adjustment and color balancing to create a printable black. In the New Black generator I have included more options for adjusting the variables that go into this mask, as well as how the mask itself is applied.
Gray Component remade In addition to Black, the script can generate a light black I have called the Gray Component.
In a CMYK separation, the lighter grays and the neutral mid values are handled by the Cyan, Magenta and Yellow channels. This makes for good tonal qualities, but makes a CMYK Black challenging to use for a spot color separation as it tends to be missing these values. The technique used for this is called Gray Component Replacement, or GCR.
The concept behind the Gray component channel is to generate a channel that prints all these gray values, as well as the values that darken the colors in an image, and to remove these values from the Black channel. This opens the possibility to print the Gray Component as a second Black using a transparent ink, while using a dense Black ink for the key lines. A Custom Black generated with a Gray Component channel will resemble a CMYK black.
While the Custom Black script has always had the Gray Component option, the current version is much more advanced and is optimized for printing. The Black, Gray and Gray Component channels all work together to provide more options for managing the values in a color separation.
Gray Ramp for Gray and Gray Component In addition to the Saturation Mask, the script also uses a curve adjustment to generate the Gray and Gray component, called the Gray Ramp. The Gray Ramp determines which values go to the Gray channels and which go to the Black. With the current build for the Gray channels I moved the Gray ramp to a new window just for generating the Gray and Gray Component.
Balancing act I have also added a function called equalize which balances the black printing over each color. This can be turned off if you prefer to make custom adjustment after the black is generated.
Imagine, implement and calibrate It is hard to overstate the amount of effort I put into the new custom Black module, but I can say with confidence it was worth it. The new Black module is perhaps the most refined component I have created, and I appreciate this every time I use it. A Black screen can make or break a print when it gets on the press, so making sure the Black is perfect may just be the most important part of the color separation process.
For detailed description check out the manual for Custom Black in the tutorials section:
With a major redesign of the main panel, core advances and fixes, the new version of YRGBK provides easier access to advanced options with improved performance and accuracy.
The redesigned interface puts the most common color separation adjustments in the first window, making the process more intuitive and manageable.
The Black, White and Gray sliders control how far into the colors the values print. (These are the saturation mask settings from the last version) The values now go from 0 to 100, with higher values increasing the amount of overprint.
The Four color sliders provide control over the Density and Saturation, as well as the amount of color in Shadow and Highlight areas. Checking the Black, White, Color or Gray boxes opens the advanced settings for that option.
The Advanced options in the secondary dialogs have been retooled as well, with more control and new adjustments. The new Black Generator offers more control over the Saturation mask as well as custom color sliders to fine tune the adjustment.
The new White scripts provide curve values and custom color adjustments all using convenient sliders.
The Color Generator New Transition Mask manages the mixing between colors for smoother transitions and softer blends. The Midtone adjustment and the Auto Option have been added as well, improving the fidelity of the image and the flexibility of the script.
Finally, the Gray Ramp is moved to a Gray dialog, which only displays when the Gray or Gray Component are being generated.
Between the main window controls and the advanced options windows, all the major variables in the color separation process can be adjusted. You can read more about it here:
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.
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.
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 customize the white channel.
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.
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. Looking at YRGBK as a color Mode, which can be printed or used to create custom separations, helps to understand its capabilities and limitations
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.