I get this message when I have -dBitsPerPixel on the command line Unexpected interpreter error -15. Error object: .putdeviceprops example call: cat /usr/lib/rhs/rhs-printfilters/testpage.ps | gs -sDEVICE=cdj500 -sPAPERSIZE=letter -r300x300 -dNOPAUSE -dSAFER -dBitsPerPixel=1 -sOutp utFile=- - > testfile
You're using one of the HP Deskjet drivers, and you're setting bpp=1, correct? The driver is broken in this respect. Try bpp=8 (that's still monochrome), or using a different driver if that's the case.
rhs-printfilters 1.46-4 no longer allows 1bpp for cdj-based drivers. This should fix the problem.