# duochrome
## English
### Etymology

From duo- +‎ chrome.

### Noun

duochrome (plural duochromes)
* The duochrome test, a test used by opticians to refine the correction of refractive error, in which the subject is asked to compare images presented with red and green backgrounds.
** 2007, Andrew William Keirl, Caroline Christie, Clinical Optics and Refraction, page 108:When using the duochrome, there may not be an exact endpoint because the chances of the spectacle refraction falling into a 0.25 DS endpoint are fairly remote.
** 2004, Nancy B. Carlson, Nancy Carlson, Daniel Kurtz, Clinical Procedures for Ocular Examination, page 99:The duochrome should be used as the endpoint procedure for the initial MPMVA .
** 2020, David B. Elliott, Clinical Procedures in Primary Eye Care, page 82:If the responses are not appropriate, then the duochrome is not reliable for this patient and should be ignored.
* An image composed of varying shades (grayscale) of two colors.
    Coordinate terms: monochrome, polychrome
** 1967, The American Pressman - Volume 77, page 24:Where a color original such as a transparency, color print, or color artwork is furnished, additional impact and interest can be obtained with the duochrome.
** 1980, Algernon Newton, Nicholas Usherwood, Algernon Newton, R.A., 1880-1968, page 1918:[…] used two tints for his underpaintings, a duochrome in effect, probably a cool grey tint for the shadows and a golden buff one for everything in sunlight.
** 1990, Richard M. Schlemmer, Handbook of Advertising Art Production, page 217:The duochrome differs from the duotone in that a fullcolor original is required for its preparation.
** 2010, Richard Misek, Chromatic Cinema: A History of Screen Color, page 21:Films could also be tinted and toned, resulting in color duochromes.
* A piece of pottery decorated in two colors.
** 1931, Studies in Ancient Oriental Civilization - Issues 13-17, page 8:Jugs 9-10 and 15 are obviously the last vestiges of earlier duochrome ware.
** 1944, American Antiquity - Volumes 9-10, page 344:Duochrome consists predominantly of red or brown on brown, buff, or cream.
** 1976, Bruce T. Ellis, Paul Alfred Francis Walter, Journal of the Museum of New Mexico, the Archaeological Society of New Mexico, the Santa Fe Society of the Archaeological Institute of America, page 16:These bowls were usually red slipped from rim edge down to several inches below the widest diameter, making the bowl a duochrome with red upper-body and tan lower-body.
** 1986, J. Charles Kelly, Jumano and Patarabueye: Relations at La Junta de los Rios, page 148:Unidentified black-on-gray (probably a duochrome related to the Chihuahua series), La Junta Focus.
* A color scheme consisting of only two hues.
** 2010, Roger Williams, The Royal Albert Hall: A Masterpiece for the 21st Century:All was immaculately in keeping, a duochrome of terracotta and brick, with niches for Elizabeth II matching those of her great-great grandparents, Victoria and Albert, on the North Porch.
** 2018, Jonathan Kellerman, Jesse Kellerman, A Measure of Darkness:A dank duochrome prevailed, matte silver and green-black, curled fog strangling the pines.
* Fabric that shifts between two colors, depending on the angle of light, also, by extension, something made with such fabric.
** 2016, Opal Carew, Meat:So she'd worn one of her own creations, a duochrome that shifted from turquoise to a rich blue depending on how the light hit it.
** 2019, Dahlia Adler, His Hideous Heart:Duochrome flecks sparkled yellow on the plane's dark seats.
** 2020, 10 Things I Hate about Pinky, page 61:I'm like—like boring old burlap and you're a duochrome, ombre, brilliant rainbow.
* A fluorochrome that shows up in either of two colors, depending on the type of biological material it stains.
** 1997, Ivan Lefkovits, Immunology Methods Manual, page 1851:[…] which seem to be positive for two fluorochromes, i.e., the intact duochrome and the first component of the disintegrated duochrome.
** 2008, Hua Gu, Klaus Rajewsky, B Cell Protocols, page 185:Commercially available Cy7 duochromes have highly variable fluorescence properties from batch to batch as there appears to be little regard to standardization with respect to conjugation ratios used.

### Adjective

duochrome (not comparable)
* Pertaining to the red and green colors of the duochrome test.
** 1960, George Henry Giles, The Principles and Practice of Refraction, page 173:Cockerham claims that there are a number of advantages with his duochrome fixation attachment over the ordinary illuminated target.
** 1976, South African Archives of Ophthalmology, page 94:the operator begins at the centre, chooses a colour, follows the colour out to duochrome balance, then proceeds to the periphery.
** 2006, William J. Benjamin, Borish's Clinical Refraction:One standard on duochrome filters recommends a green filter having a peak luminosity of approximately 535 nm and a red filter of approximately 620 nm
* Composed of two colors.
** 1998, Holly Hughes, David Román, O Solo Homo: The New Queer Performance, page 73:We were boldly duochrome in our bear-up black sweatpants and white sleeveless T-shirts with crosses and religious medals dangling from our necks, sort of a City Ballet meets St. Mark's Place kind of look.
** 2005, James Greve, Stumble Out On Deck, page 441:Duochrome monotony of gray weather recalling Cage's Four Minutes Thirty-Three Seconds of silence, making Julian hungry to see something with a feeling attached.
** 2012, Robin Boyd, The Australian Ugliness, page 42:A drab series of duochrome fashions reflected the comparatively flat progression of the country through the first half of this century.
** 2014, James Meek, Private Island: Why Britain Now Belongs to Someone Else, page 202:The initial effect is of some vast, elegant set of combination locks, or duochrome Rubik's cubes, poised at any moment to whirr and counterspin, floor by floor,
** 2022, Emma Smith, Portable Magic: A History of Books and their Readers:This required each duochrome page to go through the printing press twice, and it was soon discovered that it was more efficient to pay scribes to add the rubrication.

### Adverb

duochrome (not comparable)
* In two colors.
** 2014, Will Self, Will Self's Collected Fiction:Mark showed his father how you could push down two of the coloured ballpoints at once, and so write duochrome.