Acidic acid causes "vinegar syndrom" and will not happen with most films. The film has to have acid fixer left in it, caused by inadequate washing of the film at the time it was being processed. Most films that haven't already developed this smell most likely never will. Some older prints can have some unusual light smells such as musty or moth ball type smells. Pre-1953 blue sound track IB Technicolor prints can have what I call a pukey like smell. Agfa and Gevaert Belgium black and white film has a unique pleasent scent from the time it is a newly processed film. These other smells are common on films and have nothing to do with the acid fixer (vinegar like) smell, and they do not indicate anything is going bad.
Films in any condition might have a some curl depending on how old the print is or how bright or hot the lamp was during projection. This is common and does not cause problems or indicate anything. Some films I have had for up to 50 years, I bought them used and they had a curl to them. They are exactly the same today and are fine.
MINT or NEW - Means just that. It may have been run, but still physically looks mint, untouched by a projector.
NEAR MINT - Only the slightest physical signs of having been run. Appears mint when projected on the screen.
LIKE NEW - Can be an older print that was well taken care of. May have only the slightest signs of use, occasional minor light line or splice or minor cue mark, if any. Starting at this level, older prints may have a little curl to the film, which is common.
EXCELLENT+ - Very minimal wear or light lines at times with an occasional, although seldom, splice. No major repairs or missing scene transitions from TV use.
EXCELLENT - Will have some minimal wear or light lines and may have an occasional temporary light emulsion line, splice or minor repair. Possibly some short lap dissolves or minor cue marks around transitional scenes if it was used by a TV station, but still highly acceptable condition.
VERY GOOD - Will have some wear and lines, cue marks, minor repairs and usually more splices than desirable. An occasional emulsion scratch.
GOOD - The same as very good but with more scratches, wear and some spots that may be splicy from having been damaged. Still watchable.
FAIR or POOR - Will need to be checked for extensive repairs before running. I usually will never even list anything in this condition, only if a very desirable title.
Vintage Movie Films