ColorGPS: Dynamic Profiling Charts Instead of IT8

Why Does ColorGPS Use Dynamic Profiling Charts Instead of IT8?

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

Answer

ColorGPS calculates a new profiling chart for each printer, media and ink configuration, based on the Density Linearization measurements. Fixed standard charts such as IT8 are not used for ICC profile generation. If you need the same layout every time, ColorGPS can lock the chart to a fixed layout.

Details

How ColorGPS creates the chart:

  1. ColorGPS loads the spectral measurements of the Density Linearization.
  2. It builds a model of the printer color space and calculates the separations for all profile channels.
  3. It decides which color areas need measurements and which areas it can predict reliably.
  4. It places the chart automatically into a print job.

Why this approach:

  • The pure ink channels are already measured in the Density Linearization, so ColorGPS does not measure them again.
  • More patches go to difficult areas, for example dark colors and combinations of many inks. Simple areas need fewer patches.
  • With each additional ink channel, a uniform chart grows exponentially. A dynamic chart keeps multicolor charts at a practical size.
  • The chart is printed by ColorGPS itself, so there are no unwanted color changes or channel mapping errors. These are common when external multicolor charts are imported.

Chart size: In ColorGPS, under Calibration Chart Presets, select the Precision of calibration chart and click Calculate calibration chart. Under Size of calibration chart, No. of Patches shows the result; adjust it with the slider if the chart must fit a number of pages. Fewer patches give a less accurate profile.

Fixed chart layout: In ColorGPS, go to Options > Calibration Chart.... In the Calibration Chart Print Options dialog, enable Use fixed chart layout (no optimization to reduce number of calibration patches). ColorGPS then does not remove similar patches, and the chart quality is locked to 100%. The chart has many more patches. Use it, for example:

  • for printers with a limited ink capacity, where the dynamic chart has very few patches
  • for conventional printing, where existing screens or plates must be reused

Info
Note: ColorGPS uses the linearization data for every chart. A correct Density Linearization is the basis of every ColorGPS profile.

FAQ

Can I import an IT8 measurement to create a profile?
No. ColorGPS creates ICC profiles from its own charts only.

Can I create a profile without printing a profiling chart?
Yes, a QuickColor profile uses only the Density Linearization measurements. It is faster but less accurate. See What Is a QuickColor Profile in ColorGPS?.

Can I profile a multicolor printer with CMYK only?
Yes. On the first ColorGPS configuration page, exclude all additional profile channels. The chart and the profile then use only CMYK. Applies to: Ergosoft RIP 17.7.2.0465 and later.

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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 profiling session; only CMYK is used for the chart and the profile.
  • Changelog #15370 – Ergosoft RIP 17.5.2.0098: Ink Mixing Model, an advanced option for the dynamic ICC print chart generation (light scattering).