Thank's Alastair, I tried modifying my command lie to add the -e parameter with 3, for 3 channels, I guess (Lab = 3)? >cctiff -v -ia -e3 test.icm it8_73_basic.tif it8_73_Lab.tif But I'm still getting the same error from cctiff: > Possible photometrics for output colorspace Lab are: > 1: CIELab > 2: ICCLab > > cctiff: Error - An output photometric must be selected with the -e parameter Oops! Does that mean I should try "1" or "2" with the -e parameter? I'll try that... Roger Breton