(v13) GGS extension, HalftoneType 195

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

The RIP supports a HalftoneType, 195 which allows screens to be defined for object types:

TEXT

              <<
                /HalftoneType 195
                /Text <halftone>
                /Picture <halftone>
                /Linework <halftone>
                /Vignette <halftone>
                /Default <halftone>
              >>
            sethalftone

where <halftone> is any valid halftone dictionary.

The individual halftones are optional. Therefore, you could provide only a Text halftone if desired. The /Default entry for HalftoneType 195 is not optional.

The halftones used for object types can be any valid halftone. One expected usage is where the child halftones are HalftoneType 199 referring to standard HalftoneType 5 screens.

When both HalftoneType 195 and HalftoneType 5 are used in the same halftone directory, type 5 must be inside type 195; otherwise, the RIP errors.

There is no TransferFunction key. Transfer functions are always attached to the component dictionary that actually defines the halftoning patterns.

Screen names to match calibration sets

When installing calibration sets for any type 5 or 195 screens with multiple names, typically Halftone type 5 screens containing 199s, the RIP always matches the outermost name, which is also the one reported in the RIP monitor. For example, with the following screen definition which contains multiple names (Hds-c-gen and HDS-C) you should install the calibrations under the outermost name (HDS-C):

TEXT

            /HDS-C <<
              /HalftoneType 5
              /HalftoneName /HDS-C
              /Cyan << /HalftoneType 199 /Halftone /Hds-c-gen /HalftoneColor /A >>
              /Magenta << /HalftoneType 199 /Halftone /Hds-c-gen /HalftoneColor /B >>
              /Yellow << /HalftoneType 199 /Halftone /Hds-c-gen /HalftoneColor /C >>
              /Black << /HalftoneType 199 /Halftone /Hds-c-gen /HalftoneColor /D >>
              /Default << /HalftoneType 199 /Halftone /Hds-c-gen /HalftoneColor /Default >>
            >> def

Screen names of the type *_TS (such as /HDS-C_TS) are generated internally by the RIP. Therefore, you should avoid creating screen names suffixing _TS.