PE - my denatured alcohol uses Gameaux mixture .25% as the denaturant.
This is mostly methyl isobutyl ketone and tiny amts. of other things. Do you mean this denaturant is incompatible with photographic chems?
If you pour some of the alcohol into water and see a cloudiness form, then one of the ingredients can harm negatives. The cloudy particles can get into the negative, dry there, and leave white spots on your prints.