consdistlist Digest, Vol 31, Issue 46: 5. Cold storage for nitrate negatives (Amy Minger)
Amy Minger said: "We recently purchased a commercial grade freezer to utilize as cold storage for nitrate negatives .......runs a defrost cycle every 6 hours.......The max temperature was recorded as 19.73 degrees Fahrenheit, and the max RH was recorded as 92.33%.........how did you address these concerns?" As an institutional conservator, I had the care of nitrates in a freezer for some years. I placed them within a double bagged corrugated card acid free box with visible humidity card indicators, the contents having been pre-conditioned to somewhere between 40% and 50% RH. The box provided an insulating layer to cover any sudden temperature changes; in your case, defrost cycle temperature changes. Were I you, I would try this setup with a datalogger inside to see what RH & T graph results. Like you, I would not be happy with a max RH of 92% or for that matter, an average RH of 75.54%. I would also look into the advisability of including zeolite containing card (eg Bainbridge 'Artcare') in the box to scavenge acid gases / VOCs. James Elwing PMAICCM, private conservator Elwing & Gurney Archival, Lawson, NSW, Australia [email protected] --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus ****** Unsubscribe by sending a message to [email protected] Archives through August 2016 at http://cool.conservation-us.org/byform/mailing-lists/cdl/ Archives from September 2016 onward at https://www.mail-archive.com/[email protected]/
