Designers usually work in RGB, while printers use CMYK+N with a color space that does not fully cover the RGB color space used for display. This can be a problem in production, especially when colors cannot be printed as the designer expects.
Caldera's RGBWorkflow is an optional color management feature allowing digital printers to carry out print profiles in RGB to avoid the previous problem.
Using the same RGB profile from creation to production ensures you meet the designer’s expectations in terms of color accuracy and, as a result, the number of attempts to achieve the right color is significantly reduced, which saves time, especially for the textile industry, where pre and post-treatment of the fabric is quite important.
Good to know
The RGBWorkflow option has been available since CalderaRIP V10.1 and requires the corresponding profiling license for most users (except for those who still have the TextilePro RIP package, which included the option for free).
You might be interested in reading:
- Technical glossary (to learn about the terms mentioned above)
- Color management (to read more about the basics of color theory)
- EasyMedia (quick start to using the module)
How does it work?
By converting profiles. The color reproduction is simplified when we use ICC profiles using the same independent color space called LAB. In this case, only two conversions are made:
- Input: From RGB to LAB. For this conversion, we usually use the ICC profile embedded in the image.
- Output: From LAB to CMYK+N. The ICC profile created for the print configuration is used (considering the printer, media, and mechanical parameters).
RGB workflow overview
For the RGB output profile, two output conversions are made: from LAB to RGB, and then from RGB to CMYK+N for the printing process.
The RGB output profile can easily be exported to be used by the designers, so they can work directly in an RGB profile that considers the print configuration.
The main difference between an RGB output profile and a CMYK+N output profile is the ability to choose the desired Black before printing the profiling chart.
This chart directly takes into account the type of black you want, so you can define it as Black Only or Black Mixing depending on your media and its intended use.
Once the RGB profile is created in the EasyMedia module (or ProfileExpert in the TextilePro interface), you can export it to be used in the design process.
1. RGB output profile setup
Activate RGB profiling
- Open EasyMedia.
- Click on the wrench icon ( ) then check the box Allow RGB profiling for all printers:
Info
This option is enabled by default on some printer models.
Turn on Export of all ICC profiles automatically to quickly locate and use them for prepress tasks.
Select RGB profiling
- In EasyMedia, double-click on the printer icon.
- Select your printer then create your media.
- Create your project and choose any printing mode.
- If your profile has light inks, the first step will be the Transition between dark and light inks.
- Proceed with the Linearization and Ink limit steps.
- In the Profiling tab, select the Profiling Target (RGB with 1500 patches is recommended). Then, select RGB on Profiling Space:
- When you click Next, you will notice that the Black Separation Method is applied before printing the chart. This applies only to RGB profiles.
2. Select a black separation method
CalderaRIP allows you to fully edit and adjust your black according to the media and desired outcome.
This method uses black and light black inks only, which means that the other inks will not be part of the black reproduction:
Recommendations
- This method can be used when the black ink is good and neutral.
- Can help you to increase ink savings.
- Click here to see recommendations while working with dye-sub and textiles.
The Black Mixing method lets you choose your ink mixing to create black. While the black ink curve remains constant, you can adjust the curves of other components and incorporate small amounts of other ink colors using the corresponding fields:
- Color Start: The ink percentage at which colors begin to mix with Black.
- Smoothness: Controls how gradually the colors are mixed with the Black.
- Cyan, Magenta, Yellow: Adjust the percentage of each color to create Black. If you set it to 0, the component will not be used for black mixing.
- Black Chart... This button opens the Black Chart window (read on for more information).
Recommendations
- Use it when your combination of inks is better than pure black.
- Click here to see recommendations while working with dye-sub and textiles.
Similar to Black Mixing, GCR (Grey Component Replacement) enables you to establish a black composed of both black and colored inks. The key difference lies in creating the black with mixed ink first before adding black ink.
This method is typically employed to reduce graininess, especially in the absence of light black.
The GCR options are:
- Black Start: The ink percentage at which the black begins to mix with the sample
- GCR: Adjusts how quickly colored inks (CMY) are replaced by black ink by altering the curve's slope
- Cyan, Magenta, Yellow. Adjust the percentage of each color to create Black. If you set it to 0, the component will not be used.
- Black Chart... This button opens the Black Chart window (read on for more information).
Recommendations
- Use it when your combination of inks is better than pure black.
- Click here to see recommendations while working with dye-sub and textiles.
With this method, no black ink is used to create the Black (only colored inks are part of the mix).
The options are:
- Cyan, Magenta, Yellow. Adjust the percentage of each color to create Black. If you set it to 0, the component will not be used.
- Black Chart... This button opens the Black Chart window (read on for more information).
Recommendations
- Use it in the absence of black ink.
- It is a good choice for ceramics.
- Click here to see recommendations while working with dye-sub and textiles.
The Black Chart window is designed to help you create a reference guide, also called a Swatch Book, to help you choose the proper parameters for ink mixing.
The window is divided into three areas: Ink variations, Swatches, and Print Settings.
When all parameters are set, click the Print button to launch the Swatch Book printing.
Ink Variations
In this space, indicate for each component if its type is Variable or Fixed.
- If the color is Fixed, indicate its value in percentage.
- If the color is Variable, indicate its starting/ending values and the number of steps to get from start to end.
The number of steps tells you how many stops you will make between your ink's lightness and darkness values:
For example, if the step is 1, there will be only 2 ink tones or values (the starting and ending values). In this case, you will stop at every whole number and increase the ink's lightness and darkness values by 1 in each step. With a step of 2, there will be 3 variations: the starting tone, the median tone, and the ending tone. This means you will skip every other number by increasing the ink tone by 2 in each step. You cannot set a step above 20.
If you activate the option Same variations for all inks, the same parameters will be applied to every Variable color. If the colors (CMY) have different settings before you activate the option, the first component settings will be applied to all variable inks.
Swatches
In this area, define the size and spacing of the swatches using the Width, Height, Horizontal, and Vertical Space fields.
The option "Overinking Swatches" allows you to define your Swatch Book behavior regarding over-inking (Black Chart uses the Ink Limit set previously during the profile creation). Options are:
- Print normally: The swatch is printed despite over-inking.
- Print White: The swatch is not printed; its area is left blank.
- Remove: The swatch is removed; it will not appear on the print.
Print Settings
This section lets you adjust print parameters for your Swatch Book. There are two tabs, Standard and Special, each offering different options:
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Complete the Profile
Once you have configured the Black settings, you can finish your profile and save it for future use.
If you opt to automatically export the ICC profile in the EasyMedia Settings, it will be automatically transferred to the export folder:
3. Export and use in design software
(Photoshop example)
- Once your profile is ready, and if you want to automatically export it, you can find it in your export folder:
- You can then copy and install it on your Photoshop workstation:
- To install a profile on Windows, right-click on it and select the action Install Profile.
- To install it on Mac, copy it in the appropriate folder:
System Folder/Color Sync FolderUser Library/ColorSync Profiles - Open Photoshop and open your document. Restart if it was open during the profile installation:
- Go to Edit then select Assign Profile. Select your profile in the list:
- Click Ok. The profile is now applied to your image.
If you open the color picker, you'll notice that your color choice has been adjusted. You are now working within the gamut of your printer and the colors achievable with your print setup.