2014.03.23 20:52 "Re: [Tiff] Spot colors in TIFF", by Kai-Uwe Behrmann
With PHOTOMETRIC_SEPARATED + TIFFTAG_SAMPLESPERPIXEL == 4 + EXTRASAMPLE_UNSPECIFIED == 2 (4+2) it would be possible to some a convention.
In order to display the data a viewer would need a link of a name for the separate colour (say gold + silver) to a actual CIE*Lab value. This can be supplied by a additional ICC Named colour profile (ncl2) beside your normal ICC profile for the Cmyk data. The normal ICC profile is that residing inside the TIFFTAG_ICCPROFILE of the actual IFD. I am not sure how a second named colour profile can be defined inside one Tiff IFD.
Perhaps a completely different Tiff tag is already defined, ready to describe the colorant of the additional spot colour channels.
Am 23.03.2014 20:37, schrieb Oncaphillis:
Actually for now I just need a way to view the output of my own AGG based rendering engine which should support DeviceN and other kinds of higher dimension colour spaces. If one could point me to another tool that displays this kind of data or to a simple way to generate PSD or PDF from an in-memory bitmap representation it would be highly appreciated.