This probably counts as the weirdest question I've ever asked here, but I'm going to ask it anyway :) A while ago I managed to pick up a Polaroid HR-6000 film recorder. Basically, it's a white CRT, an RGB filter wheel and a 35mm (or Polaroid packfilm) camera and a controller board with a SCSI port. Image data is sent from the host (PC, Mac, whatever) as a {x}*{y}*3 array of bytes (usually 4096x2732xRGB for 35mm). This data is fed to an 8:8 translation LUT (which converts a byte to a byte, thus allowing PseudoColor images to be printed without applying the palette data), and then on to an 8:11 LUT which converts the final pixel values into an exposure level value for that colour channel. The problem is, all the LUTs I have are for ancient and long-obsolete film stock. I'd like to create some new ones for more modern films (i.e. stuff I can still buy - Fuji FP100C packfilm is my main target). I can load a linear LUT into the printer and expose a piece of film to whatever image I like, then measure the density levels (either with my Xrite 890 or the flatbed scanner -- colour calibrated with a Wolf-Faust target). The problem is... how would I go about turning the "exposure value E produced density D" data (I think this might count as a Hurter-Driffield curve) and converting it into a LUT? Can I do this with Argyll? If not, then what algorithms should I be looking at implementing? All the curves I've decrypted and dumped seem to follow the same format: a steep rise at the beginning, a pseudo-linear ramp, and a second steep rise towards the end. I get the impression this is somehow an inverse of the H-D curve, but I have no idea how to calculate it... About four hours of Google searching hasn't revealed anything useful :( Thanks, -- Phil. philpem@xxxxxxxxxxxxx http://www.philpem.me.uk/