With negative film, the image captured is an inverse of the image taken (i.e. black shows up as white). With black-and-white photography this is a fairly straightforward inverse of the negative to produce a positive.
Color film is more complicated. Looking at the negative directly, there’s a clear color cast†. If we simply invert the image, we have a positive image that is also color casted.
Which means that we’re going to need to adjust the colors. There are ways to do this automatically in software like Photoshop, but I typically do this manually using color curves.
I don’t think the automatic conversion works very well with my work. I’m not sure if that’s a function of my using saturated, unnatural colors and lighting, the film stocks I use, or if the automatic conversion is just not all that great.
With positive images differing so much in color, it does open the opportunity to play with HDR, combining the different color schemes into a new interpretation.