Hi Keith, I'm a bit unclear, are you going to print those negs in the darkroom eventually? If so, then a standard printing time test will quickly evaluate your negatives. That's where you expose a sheet of paper through a blank frame of the same film type, processed the same, until you reach a convincing black. Then just print your negative the same way, without making any changes to the enlarger. That can recommend adjustments in exposure and development. I can go into grater detail if you need it. On the other hand, if you're scanning to go into digital prints, most scanners have a way of changing the scanner settings to maximize the image. I never use the auto settings on the scanner. I adjust the settings to get as much detail in the shadows and highlights as possible, and then adjust the values in Photoshop. Same with sharpening.

Also, the tint on the film backing is caused by the dye that prevents halation. Different fixers and hypo clearing agents remove varying amounts of it. it is not going to interfere with image quality. Sometimes environmental factors will cause the antihalation leuco dyes to reappear over time on films that were originally clearer. It's no biggie.

Best, Doug Schwab