Fungus growth on negatives may be prevented or greatly reduced by enclosure in an envelope impregnated with a suitable fungicide. Additional protection is offered by interleaving with treated paper when more than one negative is enclosed. The most successful of the fungicides tested was sodium pentachlorophenate. Envelopes made from paper impregnated with this fungicide protected negatives against fungus growth for periods up to eight years under moist tropical conditions. The use of nonaqueous adhesives, of edge seams, and of flaps closing the envelopes also contributed to stability. Specific recommendations for storage envelopes and interleaves are made.