Applies to: Ergosoft RIP 17 and later · ColorGPS (multicolor)

Answer

Yes. ColorGPS supports up to 12 profile channels (we recommend no more than 8, light inks not counted), also when inks are in the same hue range, for example cyan and royal blue, or orange, red and magenta together. The profiling workflow is the same as for a CMYK printer: select a profile channel for each additional ink in Ink Assignment, run the Density Linearization, and create the profile in ColorGPS.

Details

Why this is a challenge: When two inks have a similar hue, many profiling solutions use the additional ink very little, or ignore it. ColorGPS includes each additional ink as a separate profile channel.

What to expect:

• An additional ink with a similar hue often gives better fill and smoother tones, but only a small gamut gain.
• Inks in other hue areas, for example orange, usually add more gamut.
• Dark inks, for example navy blue, are used less with the factory defaults. ColorGPS reserves an inner area of the gamut for the primaries, so that gradients stay smooth and dark additional inks do not interfere with the black generation and neutral tones.

The illustration shows a dark additional ink (navy blue) with the factory defaults. The blue area is restricted to the primaries; the navy blue ink is used only in a small part of its hue range:

Use the additional inks more: In ColorGPS, go to Options > ICC Color Usage and Limit..., select the additional ink under Color, and enable Soften color restrictions with a percentage. Higher values shrink the restricted area, so ColorGPS uses the ink in more colors. Values above 100% are not recommended. Then generate the profile again – no new chart is needed.

Light tones: If an additional ink causes visible dots (graininess) in light tones, clear No lightness limit in the same dialog and set Max L. ColorGPS then does not use the ink in colors lighter than this value.

Quick alternative: Job Gradation Curves > Auto Vibrancy stretches each profile channel to its full range from 0 to 100%, so the most saturated color of each channel is reached. The additional inks are then clearly visible in the print, but color accuracy is lower than with ICC Color Usage and Limit.

Tip: To see how much gamut the additional inks add, create a second, CMYK-only profile: on the first ColorGPS page, exclude the additional profile channels (Ergosoft RIP 17.7.2.0465 and later). Compare both profiles in the Gamut Viewer.

FAQ

How do I check how much ColorGPS uses an additional ink?
Use Job Gradation Curves > Auto Vibrancy: a large distance between the proposed curve and 100% shows that the ink is not used at full strength. You can also compare the output recipes in the Color Picker, or check the separated Job Preflight.

Do I need a new chart after I change ICC Color Usage and Limit?
No. Generate the profile again from the same measurements.

Related Articles

• Create Color Profiles in ColorGPS (User Guide)
• Best Practice: Fluorescent Inks in Spot Color and ICC Workflows
• Gamut Viewer
• Using the Ink Assignment Chart to find the correct Ink Assignment order

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References

• Changelog #15801 – Ergosoft RIP 17.7.2.0465: for multicolor devices, all additional profile channels can be excluded from a ColorGPS session, so that only the CMYK primaries are used for the chart and the profile.