Developing:
They must not be under or over developed. You can judge the under developing negative by looking at the markings on the side of the negative. If they are very fade, this is the sign of under developing. Under developing can slow down film speed resulting low contrast. Over developing can be seen on the exposed portion of the film leads. You should be able to see through it with a brownish black colour. Over developing can cause high contrast, coarse grain, and poor skin tone, lost of gradation. Old chemistry can cause poor cyan colour. Sky will not appear as blue as it should.

Bleach:
You can judge under bleach by inspecting the film base side if it has a silvery image on it. Over bleach would not cause trouble.

Fix:
The unexposed portion of film should be clear to see through. Traces of white or milky colour left over are caused by under fix. Over fix would not cause any trouble. Old fixer can deposit metal silver back into film.

Stabilizing:
Improper stabilizing can cause colour fading in few years time. Bacteria will grow in the emulsion.

Cleanliness:
There should be no processing marks, dirt, dust, fingerprints left on the negatives.

Developing:
It should have good contrast, darkness, and whiteness, skin tone, gradation. Old chemistry can cause stain. Red colour appears brownish, lost of contrast. Under develop will make black colour looks purple. Over develop will make high contrast, lost of gradation.

Bleach/Fix:
Over bleach can cause lost of black colour. Picture appears brownish. Under bleach will make yellow looks greenish. Skin tone looks dark.

Wash:
Insufficient wash can make colour fade out in short time.

Cleanliness:
There should be no processing marks, dirt, dust, fingerprints left on the paper. The picture on the right has process mark is caused by dirty rollers.>