Test Method for Rating Abrasiveness of Photographic Interleaving and Enclosure Materials

Test Method for Rating Abrasiveness of Photographic Interleaving and Enclosure Materials Test Method for Rating Abrasiveness of Photographic Interleaving and Enclosure Materials By Maria S. Holden, Conservator Uew York State Archives This paper is a progress report of research into the abrading propensity of some materials used in the interleaving of historic photographic albums and prints. The aims of the project are to: - develop a procedure to measure the abrading propensity of interleaving materials and - Systematically rank the 12 or so materials commonly used to interleave according to abrading propensity. A test procedure has been developed and is described in this paper. Three interleaving materials have been tested with satisfactory results. While this project is confined to the testing of album interleaving materials, it is hoped that the findings will be useful in the evaluation of materials used BS enclosures for unbound photographs. Many of the same materials are used for both purposes. There are many features typical to the structure of historic albums which contribute to the deterioration of the photographs housed within them. Some of these are: - the use of potentially harmful materials in the album construction, such BS acidic or ligneous paper or board, and chemically active mounting adhesives; - distortion of the leaves Over time, which can result in the exposure of the photographs to Werse environmental conditions such as high temperature and relative humidity, and pollution; - the presence of gilt borders and ornamentation which has been essociated with image deterioration; - photograph-to-photograph contact, which may cause problems when platinum or platinum-toned photographs are present, - uneven pressure on the photographs due to the disparate contents and parts and - abrasion due to the combination of weight and movement during handling. When deterforetion in the form of staining caused by prolonged page to page, photograph to photograph contact is present, that deterioredion can be arrested with the addition of an interleaving sheet. An interleef should also protect the photographs in rn album from further physical dunage by mitigeting the effects of abrasion arrd urn pressure. The chemlcel interactions between sane historic photographic processes and enclosure 12 materials have been addressed in recent and continuing studies. However, the physical interactions between these two components have been little explored tlethod of abrasion The test procedure developed to measure the abrading propensity of interleaving materials consists of two park the abrasion mechanism or means by which abrasion is produced in a laboratory setting, and the rating of the degree of abrasion to yield a numerical value. The second aspect has turned out to be the more challenging one. The term abrasion is used here to denote all forms of surface marring. The rub testing was carried out at the Image Permanence Institute in Rochester using a manually operated rub tester called the UW abrasion tester, which is manufactured by Huber. This machine enables one to move two contacting surfaces, in this me, the photograph and interleaving paper sample, against each other, producing abrasion. The machine consists of three parts: 1 ) the guiding frame with cycle counter, 2) the abrasion carriage which glides alongthe frame and 3) a metal block with an area of 50 x 52 mm2 and mass of 500 g, producing a total load of .27 lb/ in2. The photographic print is plaaxl face up on a smooth, flat surface under the guiding frame. The interleaving paper sample is placed on the abrasion carriage with the side to be tested facing the photograph's emulsion. The weight is placed in the abrasion carriage, over the paper sample. The abrasion carriage is moved backward and forward manually. The abrasion movement is linear--in a path 2 x 10 cm. The number of cycles is recorded by the counter device. One cycle equals one backward and forward movement. The machine is designed so that hand pressure applied to the carriage does not contribute to the load. Several variable test conditions were tested for their effects on the degree abrasion produced. The rub heavier load was achieved by placing steel weights on the machine's 500 g metallic block. The number of cycles per rub test was also varied; sets of 10,20,40, and 80 cycles were run per paper sample. testing was performed using two different loads, .27 lb/in % and twice that, .54 lb/in2- The The testing was carried out in a climate-controlled room at the Image Permanence Institute. The RH was 50% and the temperature 70a F. Relative humidity can have a significant effect on the abrasion resistance of photographs, as the moisture content of photographic supports and emulsions changes witb changing relative humidity. The effects of humidity on abrasion are discussed at length by Carroll and Paul in their article "Test Methods for Rating the Abrasion Resistance of Photographic Film" in Photoarmhic Science and Enaineerina,volume 5, number 5, 1961. All paper samples and photographic prints were preconditioned in the testing environment for 20 hours prior to testing. Abrasion testers is widely used in textile testing industry.