Klett-Summerson photoelectric colorimeter
Date: circa 1950
Inventory Number: 2006-1-0003
Classification: Colorimeter
Maker: Klett Manufacturing Corporation (fl. 1890 - 1990)
Seller: Will Corporation (1919-circa 1970)
Cultural Region:
City of Use:
Dimensions:
without cord: 22 × 16.3 × 44.7 cm (8 11/16 × 6 7/16 × 17 5/8 in.)
DescriptionThe colorimeter sits on top of a metallic base, rectangular and moderately thick. The entire base is propped up by four rubber feet - one on each corner. The base's front face is inclined at a forty-five degree slope.
Covering the front three quarters of the base is an enclosed aluminum box, the right side of which features a switch; the front face of the box, which is similarly sloped, has at its center a large black circular dial made of plastic, underneath which is a slim horizontal window featuring scaled units (in the hundreds).
The front half of the top of the box is covered by another enclosed metallic box, smaller and flatter than the main box; its front face, again similarly sloped, features another slim horizontal window, outside of which is a dark red arrow meant to be calibrated to align with the thin vertical line inside the window.
On the top of the back half of the main box are several smaller dials.
The back quarter of the base is covered by a metallic arch, enclosed, although with many circular holes perforated into it. On the front face of the enclosed arch, atop another smaller metallic box connecting it to the main box, is another switch.
A power chord is attached to the back of the arch.
Stickers and a plaque identify this object as being used at Brandeis University.
Covering the front three quarters of the base is an enclosed aluminum box, the right side of which features a switch; the front face of the box, which is similarly sloped, has at its center a large black circular dial made of plastic, underneath which is a slim horizontal window featuring scaled units (in the hundreds).
The front half of the top of the box is covered by another enclosed metallic box, smaller and flatter than the main box; its front face, again similarly sloped, features another slim horizontal window, outside of which is a dark red arrow meant to be calibrated to align with the thin vertical line inside the window.
On the top of the back half of the main box are several smaller dials.
The back quarter of the base is covered by a metallic arch, enclosed, although with many circular holes perforated into it. On the front face of the enclosed arch, atop another smaller metallic box connecting it to the main box, is another switch.
A power chord is attached to the back of the arch.
Stickers and a plaque identify this object as being used at Brandeis University.
In Collection(s)
Signedon plaque, front: KLETT MFG. CO.
on plaque, back: WILL CORPORATION and subsidiaries / Rochester 3, NY. Atlanta 1, GA. New York 12, NY. Baltimore 3, MD. Buffalo 5, NY.
on plaque, back: WILL CORPORATION and subsidiaries / Rochester 3, NY. Atlanta 1, GA. New York 12, NY. Baltimore 3, MD. Buffalo 5, NY.
Inscribedon plaque, front: PHOTOELECTIC COLORIMETER / PAT. NO. 2193437-1940, KLETT MFG. CO. N.Y. U.S.A. / MODEL 800-3 / VOLTS 115 / SERIAL 18900 / MAX. WATTS 100.
FunctionA photoelectric colorimeter measures the absorption of particular wavelengths of light by a specific solution - put plainly, that solution's color. By precisely quantifying the solution's color, one may thereby derive more information about the solution - most commonly, the turbidity and/or the concentration of a known solute. The latter is measured using the Beer-Lambert Law which states that the
absorption of light is proportional to the properties of the material through which it is travelling, To do so, one would compare a sample of solution with a known amount of the known solute with a sample of the solution with an unknown amount of the known solute and quantify the difference.
The photoelectric colorimeter is composed of: a phototube or photocell (see 1996-1-0440 and 1996-1-0441), a color filter (used to select the wavelength of light which the solute absorbs the most in order to maximize accuracy), an amplifier, and an indicating meter. The Klett-Summerson colorimeter had its own arbitrary unit to measure optical density (dubbed the 'Klett Unit'); Klett colorimetry instruments were widely used in American biology and chemistry labs in the 1940s, 50s, and 60s,
allowing the units to be shared among their users.
absorption of light is proportional to the properties of the material through which it is travelling, To do so, one would compare a sample of solution with a known amount of the known solute with a sample of the solution with an unknown amount of the known solute and quantify the difference.
The photoelectric colorimeter is composed of: a phototube or photocell (see 1996-1-0440 and 1996-1-0441), a color filter (used to select the wavelength of light which the solute absorbs the most in order to maximize accuracy), an amplifier, and an indicating meter. The Klett-Summerson colorimeter had its own arbitrary unit to measure optical density (dubbed the 'Klett Unit'); Klett colorimetry instruments were widely used in American biology and chemistry labs in the 1940s, 50s, and 60s,
allowing the units to be shared among their users.
Curatorial RemarksCopy of instruction manual is in the instrument file, CHSI Library. Pricelist included in said book is dated January 1, 1950.
The patent of this instrument can be seen online here.
The patent of this instrument can be seen online here.
ProvenanceUsed by the Department of Microbiology, Brandeis University. Given to CHSI by Toby Sommer, Freidland 203, MS009, Brandeis University, Waltham, MA 02454-9110.