from RAW source
According to hdrsoft.com calibrating response curve of a digital camera is a nonsence. Is that right? This might be true for HDR purposes, but what about raw processing. Application of camera curve does make a difference in UFRaw. But no other software that I have seen uses device curve. All of them use luminosity correction curve. 
I have writen a tutorial on RAW processing using UFRaw. It is located here
I have figured out how to calibrate my Canon RebelXT camera for use with UFRaw. I managed to create .curve file that can be used as Base curve. Curve is in the attachment. I think I can calibrate any camera using this technique.
This shot is made on Eliott Falls in Ontario, Canada. The falls are small and water flow is not significant. But fluctuating water level creates wonderful imagery in sub zero temperatures because all submersed rocks form ice rims. Here is one of those rocks. Doesn’t it look like a gem?