A-1671 Use of KODAK Brown Toner to Extend the Life of Microfilm
Introduction Methodology Microscopic Blemishes Molecular Sieves Some processed silver gelatin microfilms in storage from two to twenty years have developed microscopically small colored spots or blemishes. The fogged leader at the outside of the roll is most frequently affected by the blemishes, which are generally red or yellow in color and are smaller in size than the image characters (for example, a typewritten letter reduced 20X) on the microfilm.
The Image Permanence Institute (IPI) at the Rochester Institute of Technology (RIT) in Rochester, New York, extensively researched redox blemishes in microfilms.7 IPIs research showed that selenium toning did not effectively stop the spread of redox. IPI then looked at a polysulfide solution and Kodak Brown Toner solution in place of selenium. IPIs testing showed both solutions stopped the migration of redox blemishes into the roll of microfilm.
For Table Top Processors* Conclusion Mix the brown toner solution at a dilution of 1:25 (1 part brown toner to 25 parts water). The temperature of the brown toner solution should be 1000F. If the machine speed varies, adjust it to allow for a minimum of 25 seconds of dwell time in the brown toner solution. Kodak Brown Toner, using the procedures described above, has been shown to meet ANSI specifications for satisfactorily toned film as described in ANSI/NAPM IT 9.15-1993.
References 1. Inspection of Processed Photographic Record Films for Aging Blemishes, C.S. McCamy, National Bureau of Standards Handbook 96, January 24, 1964. 2. Microscopic SpotsA Progress Report, D.G. Wiest and R.W. Henn, National Micro-News, 70, 249257, June 1964. 3. Microscopic Spots in Processed Microfilm Their Nature and Prevention, D.G. Wiest and R.W. Henn, Photographic Science and Engineering, 7 (5), 253-261 (1963) and Micrographic Spots in Processed Microfilm: The Effect of Iodide, R.W.
