help with image processing

[daine042]

I took a few exposures of m42 last night and i thought id have a go at processing them today theres 9x 30 sec exposures and 15x 5 min ones with 2 darks i used my nikon d90 for them, i have stacked both image sets individually using deep sky stacker in the hope to merge the final 2 images in photoshop that was going fine until i tried adjusting the curves and colour both options are not available what have i done wrong?

[RickS]

Your image is probably 32-bits per channel. I think you'll need to convert it to 8 or 16 bits per channel before you can use those tools.

[LewisM]

Yup,32 bit TIFFs. Save them as 16 bit TIFFsin DSS, or convert them to 16 bit TIFF in Photoshop (Image:Mode:16 bits/channel). It will go into an HDR routine if you use PS to do the conversion, so be prepared to go minimalist (which is why I save in 16 bits in DSS)