(v13) Parameters for the LIBTIFF and FRAMETIFF raster backends

This page applies to Harlequin v13.1r0 and later; and to Harlequin Core but not Harlequin MultiRIP.

Some details of the processing performed by these raster backends can be controlled by using RasterParams; see (v13) Structured data parameters for raster handlers.

As from Harlequin v13, you can set three parameters:

1 CompressionType controls how the raster data should be compressed within the TIFF file. The value should be a string - one of: (Flate), (LZW), (PackBits), (CCITT4), or (None . The default is (LZW) . CCITT4, which was added in Harlequin v13.

2 ExpandTo8Bit, if set to true, writes the TIFF file using 8 bits per pixel, if it is screened to 1, 2, or 4 bits per pixel in the RIP and is composite color. It is not applied for separations or for mono output. This can be useful during development, as many TIFF viewers cannot display 2- or 4-bit rasters, or 1-bit composite color. The default is true.

3 PhotoshopFriendly, if set to true adds a Photoshop tag to the TIFF file when outputting spot color channels, which defines the colors and names of the extra channels. In addition, the data of the spot color channels is inverted for CMYK TIFFs. This is for display purposes in Photoshop.

The actual raster data in the spot color channels is inverted, so sending a TIFF file produced with the LIBTIFFPS backend to a printer will not produce the same output as a TIFF file made using the other TIFF backends. We anticipate that PhotoshopFriendly is of most value in rapidly previewing the RIP output during development and test, rather than for production use. The default is false.

For example:

TEXT

                        <<
                          /ExtraPageDeviceKeys <<
                            /RasterParams <<
                                /LIBTIFF <<
                                  /CompressionType (Flate)
                                  /ExpandTo8Bit true
                                  /PhotoshopFriendly true
                                >>
                            >>
                          >>
                        >> setpagedevice

The value of DEMOTIFF is supported for PageBufferType and -o for backwards compatibility; before Harlequin v13, it was a separate raster backend with slightly different properties to LIBTIFF. Its use is deprecated from Harlequin v13 onwards. It uses the LIBTIFF raster backend, but CompressionType defaults to (None) and ExpandTo8Bit defaults to false.

In the same way, the value of LIBTIFFPS is supported for PageBufferType and -o for backwards compatibility; before Harlequin v13 it was a separate raster backend with slightly different properties to LIBTIFF. Its use is deprecated from Harlequin v13 onwards. It uses the LIBTIFF raster backend, but PhotoshopFriendly defaults to true.

The key used in the RasterParams dictionary should match the value of the PageBufferType even if the -o clrip.exe command-line argument is set to a different value.

The same parameters may be used to control FRAMETIFF; to do so, the key used inside RasterParams should be /FRAMETIFF rather than /LIBTIFF.