Photoink devices

This page applies to Harlequin v13.1r0 and later; both Harlequin Core and Harlequin MultiRIP

Inkjet devices often improve tonal control by using light and dark inks to cover different tonal ranges for some of the CMYK components. One common method is to use CcMmYK inks that use light and dark inks for cyan and magenta, six inks in total. The general technique of splitting into multiple inks is referred to as “photoink”. These devices require special handling for color management.

For the sake of simplicity and the ability to use standard tools, color management should use a CMYK model. This requires that the splitting into light/dark inks occurs after color management, whilst the colorant configuration and screening requires a /DeviceN device to control the individual inks. This is achieved using the RIP’s photoink mode. The RIP is put into photoink mode with this setpagedevice key:

<< /CalibrationColorModel /DeviceCMYK >> setpagedevice

which will cause the RIP to treat the device as /DeviceCMYK for calibration and color management, and as DeviceN for screening. Therefore, the techniques for color management of CMYK devices may be used unchanged from the examples throughout this chapter.

The RIP supports photoink devices that are /DeviceCMYK, /DeviceRGB, or /DeviceGray. In principle, an XG colorant set could be used in a photoink device. For example, CMYKOG, could be split into light and dark inks, but the RIP does not support these.