The pdf14 compositor currently does not support blend color spaces when the target device is a separation device (e.g. tiffsep or psdcmyk). When Ray completes his overprint compositor the overprint compositor will appear to the pdf14 compositor as a separation device and we will have issues with that work flow also. There are several items that need to be addressed. 1) If the blend space is RGB or Gray based, then we need to ensure that the alternate tint transform is not used when we encounter a separation or DeviceN color space. (assuming we have not run out of spot color space at the target device). Note that if the any of the spot colors in a DeviceN color space are CMYK process colorants and the blend space is Gray or RGB, the alternate tint transform IS used. 2) The pdf14 compositor must be able to handle a mixture of additive and subtractive components. I.e. RGB + spots or Gray + spots. 3) If the blend mode is non white preserving or not separable, then the spot colors use the normal blend mode while the process colorants use the specified blend mode. 4) The color swapping code could use some major cleaning and that will be a part of this work.
Fixed with http://git.ghostscript.com/?p=ghostpdl.git;a=commit;h=c9d8618934ebf682f72dd9b3ebef48b2be535a8d and http://git.ghostscript.com/?p=ghostpdl.git;a=commit;h=47294ff5b168d25bfc7db64f51572d64b8ebde91