Heat and humidity are not kind to historic photos and documents.
Karen Keehr, photography curator for History Nebraska, spoke to the 2019 Nebraska Country Schools Association conference attendees on Friday, July 19, about how to conserve old photos and documents.
Keehr said the ideal archive environment for photos and documents is about 65 degrees Fahrenheit with about 40 percent relative humidity.
Photos exposed to higher humidity levels are prone to fading and fungus, said Keehr, while those kept in low-hummidity conditions may become brittle.
Historic photos and documents should not be stored in basements, garages, attics, or barns, said Keehr, because temperature and relative humidity cannot be controlled successfully in these situations.
Keehr suggested storing such items under the bed, where the mattress and bedding can help stabilize the temperatures.
“All light is bad for photos,” said Keehr, adding that any light damage is permanent.
She noted that albumen prints and cyanotypes, which are older types of photographs, are particularly susceptible to light damage.
She added that color photo prints from the 1960s and 1970s may seem to be turning yellow, which is partly true.
Two of the four colors used in printing process, cyan (blue) and magenta (red), are fading more quickly than the yellow colors in the prints, said Keehr.
Keehr advised the audience to display copies of historic photos whenever possible while storing the originals in complete darkness.
Other photo display tips she offered included not hanging or displaying photos in direct sunlight, choosing glass with UV protection, using archival frames and mats, and monitoring fading by occasionally removing the photo from the frame to see if the area under the mat looks darker or different than the unmatted area.
Keehr said the Ford Conservation Center in Omaha is a good resource for photo preservation questions. Call 402-595-1180 or email hn.fordcenter@ nebraska.gov with your questions.

People cause the most damage to historic photos and documents, said Keehr, who recommended wearing cotton or nitrile gloves when handling historic materials.
She suggested using both hands when handling old photos, supporting the photo on its long edges, and moving it or carrying it on piece of acid-free paper.
Other speakers for the two-day conference included Taryn and Jon Vanderford, hosts of “Pure Nebraska,” who discussed country schools they have toured; Gloria Christensen, who spoke on the Antelope County Country  School District No. 70; Ardis Yost and Suzi Schulz, who told stories of North Star School in Red Cloud; and Mary Ann Gabel and Caroline Allen, who talked about bringing the country school experience alive for students today. The Lied Lodge and the Wirth Foundation provided sponsorship support for the conference.