Vintage Kodak Darkroom Thermometer, Made in USA, 1970s-1980s - Tested

This vintage darkroom thermometer still works – see photos for its reaction to hot and cold water.
 
Kodak produced various thermometers specifically for darkroom use in photography, ensuring precise temperature control for developing chemicals. These items are no longer manufactured. 
 
They were designed to be easily read in the dim light of a darkroom, with a high-contrast ink fill in the tube. 
 
This one features a yellow background and dark blue liquid column, which we believe is blue-dyed alcohol rather than mercury, but we could be wrong. According to our online research,the "yellow background with blue dye" Kodak darkroom thermometer was a version specifically designed for color photographic processing, particularly for the C-41 process, which Kodak introduced in 1972. That would date this piece from 1972 to the early 1990s, when digital photography began its takeover.
 
Measurements are in Farenheight from -40 to 120°F, with 10° increments. Stars mark correct developer temperature at 70°. The back of the thermometer is marked KODAK DARKROOM THERMOMETER /  MADE IN USA FOR EASTMAN KODAK COMPANY ROCHESTER , NY / TRADE MARK REG. US PAT. OFF.  
 
H 5 3/4” x W 1/2” x D 1/8”
 
Disclaimer: We have tried to make sure colors shown in photos are representative of the real colors of each item. We have tried to identify all imperfections in descriptions, but we may have missed some. If you are unhappy with your purchase, let us know.