Thermometers

A thermometer stands along with film, reels, paper, tanks and chemical baths as some of the important accessories in a photographer's darkroom.

Most people know that thermometers measure temperature in Fahrenheit and Celsius degrees. The way they do this by using materials, mercury or alcohol, that change when exposed to hot or cold substances.

People have used different types of thermometers since the sixteenth century. Recorded history of thermometers date back to 1596 with Galileo Galilei. Though many historians say he actually invented a thermoscope since his invention indicated temperature differences, not measured them. In 1612, an Italian named Santorio Santorio invented the first recorded thermometer when he applied a degreed scale to an air thermoscope.

The first person to make a mercury thermometer also incorporated a fixed scale to it. Gabriel Fahrenheit divided the freezing and boiling points of water to come up with the Fahrenheit scale. This method is one of two still used today. Anders Celsius created the Celsius scale 1742, but not as it is known today. In 1743, Jean Pierre Cristin used the original Celsius scale to create the Centigrade scale, which is the Celsius measurement still in use today.

Over the years different inventers came out with different types of thermometers. There is the mercury in glass thermometer that once was used to measure body heat. The Basal thermometer is used to take body temperatures upon waking. Alcohol based glass thermometers, electrical resistant thermometers, liquid crystal thermometers, and reversing thermometers all provide specific uses.

An infrared thermometer and a digital thermometer both aid a photographer in the darkroom. Some thermometers use alcohol as the liquid instead of mercury to eliminate any risk of contamination should the thermometer break. Oakton offers an infrared thermometer which measures both non-contact and contact temperatures. The screen lists both temperatures at once for easy processing. The laser sighting helps for precise temperature readings. The distance to target size is a 11:1 ratio. It takes both Fahrenheit and Celsius measurements and can read up to 932 degrees Fahrenheit in infrared mode, and 1999 degrees Fahrenheit when in contact.

Kaiser makes a digital thermometer that includes a probe and LCD display. The four temperature display reads temperature in both Fahrenheit and Celsius degrees. It includes a timer with a maximum setting of ninety nine hours and fifty nine minutes.

Both the Kaiser digital thermometer and the Oakton infrared thermometer run on triple A batteries.