>>2693088iirc this was my good flow.
crop into the image enough so it's just your shot (no borders)
set your white balance on something that's as close to neutral grey as you can find
adjust each RGB channels curves so you top and tail the histogram for each colour
invert your main curve to invert the negative
adjust the levels of each RGB channel again paying close attention to colour shifts in the highlights/shadows
if you upload a raw I'll see what I can get and screen shot my settings. The pic attached is one I just did using JUST the workflow above and no other changes to the image except brightened by 0.3 and saturation at -10. I would usually then go onto my normal (inverted) lightroom digital workflow.
