I use a computer for characteristic curves of film (very useful) and paper (hardly useful at all). I have a database of the images, which helps me to find pictures fairly quickly, and I keep notes of how I make prints, so I can easily make more prints.(posted 8834 days ago)I suppose a densitometer on the negative (or meter on the enlarger baseboard) could give you basic exposure and contrast information, but with experience you should be able to get that in a single print, and that print will then give you information about required local variations in density or contrast.