Understanding Neutron Radiography Reading V-Kodak Part 2 of 3

Commercial Keeping
Since definite retention times for radiographs are often specified by applicable
codes, archival keeping may not always be necessary. Recent studies 3 have
indicated that industrial x-ray films, with a residual thiosulfate ion level of up to
5 micrograms/cm 2 , per side (as measured by the methylene blue method
described in ANSI PH4.8) 4, should retain their information for at least 50
years when stored at 0 to 24°C (32 to 75°F) and a relative humidity of 30 to
50 percent. Peak temperatures for short time periods should not exceed 32°C
(90°F) and the relative humidity should not exceed 60 percent. Storage
conditions in excess of these ranges tend to reduce image stability. The
extent of reduced image stability is very difficult to define, due to the great
number of conditions that could exist outside of the above suggested storage
condition ranges. It should be noted that this does not imply that industrial x-
ay films with a total residual thiosulfate content of 5 micrograms/cm 2 , per side,
will have archival keeping characteristics. It does, however, suggest that
these films will fulfill the needs of most current users of industrial x-ray film
requiring a storage life of 50 years or less.
Charlie Chong/ Fion Zhang
Radiography in Modern Industry. Rochester, NY: Eastman Kodak Co. 1980