What Do We Mean by Room, Cool, Cold, and Frozen?
Currently, there are no standard definitions for the terms room, cool, cold, and frozen when used in the field of preservation. The terms are relative and ambiguous, even though we all have a personal sense of what they might mean. The only exception is “frozen” which refers to the temperature at which water becomes solid. This is 0°C or 32°F. But to someone living in a hot climate, room temperature may mean 77°F, but to another living in a cold climate it could mean 65°F. The only thing we seem to have in agreement is the order of the terms with frozen being the coldest, followed by cold, cool, and finally room as the warmest of the four.
To address this, IPI uses a set of temperature “anchor-points” with allowable deviations both up and down the scale to describe the four terms and help institutions quantify their various storage areas. They can be found in IPI’s Media Storage Quick Reference (MSQR), 2nd Edition.
The anchor points for ROOM, COOL, COLD, and FROZEN are shown in the chart on the right. Using the chart and data gathered through your own environmental assessments, you should be able to place each of your storage environments in one of the four categories. Of course, it’s very likely that your storage temperatures will not exactly match any of the four anchor-points shown in the chart. In this case, if your real-life average temperature is closer to one anchor-point temperature than another, simply apply the closer category. For example, if your storage temperature is 50°F (10°C), your environment would be considered COOL.
The MSQR also provides a chart to show the appropriateness of each storage condition for a variety of imaging media as well as magnetic tape and optical discs. For inkjet-printed photographs the guide indicates that room and cool are “Fair” for inkjet but cold is “Good” and frozen is “Very Good”. However, data generated since the publication of the MSQR in 2009 would now suggest that inkjet should not be stored at room temperature, but at least at cool.