PDF transparency
This page applies to Harlequin v13.1r0 and later; both Harlequin Core and Harlequin MultiRIP.
In PDF, the blend space of a transparency group may be /DeviceCMYK, /DeviceRGB, /DeviceGray, /ICCBased, /CalRGB,
or /CalGray.
In some jobs, colors may be converted multiple times between groups with different blend spaces. It is, though, more usual that jobs use a single blend space for all groups.
ICCBased
blend spaces must use bidirectional profiles for converting both into and out of the blend space.