Subject: Picric acid danger Glue sticks Microfiche, enclosures and ANSI standards
Anyway, I just had a peek to see if I could help you locate the picric acid comments. No wonder you don't remember it - it's dated 9/22/88 and was from one of the "annual" collections (I had requested it to catch up with things since I had only joined about a year ago.) **** Moderator's comments: here is the item in question, which is in Year2.dst: Spot test for collagen: place particle in a drop of FUCHSIN and PICRIC ACID. Soak for 1 minute, rinse with water droplets until clear. Collagen will stain deep red. (From Raff, Leather Cons. News. citation on request.) The mixture you mentioned for collagen spot testing was fuchsin and picric acid. All the bottles of picric acid that I've worked with had several inches of water on top. Merck says: "Keep in a cool place and remote from fire. Explodes when rapidly heated or by percussion! Incompat: All oxidizable substances, albumin, gelatin, alkaloids. Note: For safety in transportation, 10-20% water is usually added." As a short catch up note, I remember seeing a number of postings about glue sticks. We had tested tested the effects of a number of glue sticks on photographic materials during the development of the PAT (Photographic Activity Test) in ANSI IT9.2-1990. Something in the glue sticks tested was quite aggressive. Mainly there seemed to be a non-homogeneous component causing localized attack on the silver detectors. Re: microfiche, enclosures and the ANSI standards: a) individual enclosures do help, but the advantage may not be as noticeable in heavily used collections. Often physical damage is so much worse than anything related to storage that the enclosure (or number of fiche per envelope) doesn't matter. However, for purists, the point of an envelope is to provide individual protection for the object. b) Note that the enclosure used should meet the requirements of ANSI IT9.2-1990. This is the enclosure standard for photographic materials. c) The ANSI standard frequently quoted in library manuals and standards is for storage copies only. Use copies are not included in the standard because of the added problem of physical abuse. However, all other things being equal, storage (and use) under the conditions given for optimum storage should help to promote optimum life even in use copies. However, if the storage and use environments are too different then the fluctuations caused by removing and returning the fiche into storage may cause worse degradation problems. d) ANSI is changing the storage standard (expect the new standard available in late 1991 or early 1992). At the May meeting in Ottawa, the IT9 committee approved a number of changes including: 1) Recommended storage humidity lowered to 20-30% RH. Although this may cause the gelatin to be more brittle, and shrink, studies on rabbit glues, gelatins and related materials seem to show that gelatin can handle quite a bit of tensile stress. In addition, storage copies are not expected to see much handling and therefore brittleness is not expected to be a problem. This change (from the original 15 to 50% RH recommendation) has occurred because of the amount of data that shows that gelatin lasts longer under lower humidity, the gelatin "closes up" and protects the silver much better under lower humidity, dyes last longer under lower humidity and the film support (particularly acetates) last much longer under lower humidity. Data from the safety film project here at IPI, have shown that the benefits of low humidity storage are far more significant than was once thought. The IT9 committee looked at the data and agreed that the benefit seemed to outweigh the added cost of improved dehumidification that the film storage standard was revised. 2) The terms "medium term", "long term" and "archival" have been removed from the text and replaced by "LE" numbers. The LE numbers are very conservative Life Expectancy numbers. *** Conservation DistList Instance 4:56 Distributed: Sunday, April 28, 1991 Message Id: cdl-4-56-009 ***Received on Friday, 26 April, 1991