Avoid using libtiff which cannot handle cctiff’s output
Avoid using libtiff which cannot handle cctiff’s output

Besides, this makes the cctiff call faster.  The libtiff error was:

    convert-im6.q16: Sorry, can not handle image with Samples/pixel=3, colorchannels=3 and Bits/sample=16. `/tmp/tmpsxstgfgu/000001-temp.tiff' @ error/tiff.c/TIFFErrors/606

bronger/kamscan,bronger/kamscan,bronger/kamscan