Boulder, Col.; founded in 1877; reported at the end of 1919: Professors and instructors, 200; students, 1868; volumes in the library, 118,500; income, $600,000; president, George Norlin, Ph. D.
COLOR BLINDNESS, a peculiar defect of sight in which those who are affected are incapable of distinguishing different colors. Some see everything either to be light or dark, and have no conception of any other colors. This condition is, however, happily rare.
COLOR HEARING, a vision of colors, which in some persons is thought to accompany their perception of sounds. Known also as Color Audition.
COLOR LINE, a line of social distinction drawn between the white people and negroes in the United States.
COLOR PHOTOGRAPHY, a system of photographic reproduction of objects in their own colors, which should not be confused with colored photographs. The successful accomplishment of this has long been desired, and has been the subject of much research and investigation, but even to-day it is generally felt that the best solution has not been found. Although one large manufacturer of photographic apparatus and camera has had a staff of scientists at work on this problem for years, and has had several exhibitions of the work of this laboratory, there has been no introduction of a popular system of color photography.
Early experimenters, such as Edmond Becquerel, G. W. Sempson, and Robert Hunt, produced daguerreotypes and other prints in which colors other than the customary gray or brown appeared.
Modern investigation is along two general lines, one the principles of which were laid down by Gabriel Lippmann, of Paris, which system utilizes the difference in wave number of the different colors.
The other system is founded upon the work of Dr. J. Clark Maxwell, of Cambridge, who proved that, by the proper adjustment of red, green, and blue, any desired color of the spectrum could be produced.
In 1915 Frederick E. Ives introduced a process in which the print is made directly from the negatives upon the print paper, which was a marked improvement. In the Ives process a camera with plates sensitized to red, green, and blue. After exposure the three plates are developed in a tank, and the print from the blue plate is made upon specially prepared paper, while the prints of the red and green negatives are made upon transparent films, which are then laid over the blue print and properly located. From this combined film, any number of prints may be made.
COLOR PRINTING, the art of producing pictures, designs, cards, etc., in various colors by means of lithography, printing from metal blocks, etc. The ordinary methods are: (1) the chromo-lithographic, in which a tracing of the original picture, or the like, is first made and a copy transferred to as many stones as there are colors in the original, every color requiring a fresh stone. The drawing on each stone is made to fit in, or register, with the preceding one, and as the paper passes through the machine an additional color is added every time, and thus the picture is built up color upon color (each being allowed to dry before the next is put on) until it is completed. Some chromos or oleographs may have as many as 25 or 30 printings or colors. (2) Block or surface color-printing is specially adapted for book illustrations or similar work where nicety of detail or rapidity is required. As in chromo-lithography various printings are necessary; but these, while producing similar effects, are reduced in number by a method of printing several tints of the same color at one operation. Each block, which is usually of zinc and prepared in the usual way, is capable of producing three or more gradations of the same color; the darkest shade from the normal surface, lighter shades being got from parts which have been bitten or corroded in an almost imperceptible degree—the deeper corrosions giving, of course, the lightest shade. When all the tints of one color are thus printed from one block and at one operation, a second block with gradations, in the same way, is used, registering as in chromo-lithography, and so on until the picture is finished.
COLOSSÆ, an ancient town of Asia Minor, in the S. part of the province of Phrygia, on the Lycus river 12 miles E. of Laodicea. It is mentioned by Xenophon as “a populous city, prosperous and great,” but in the time of Strabo had become “a small town.” It was ruined by an earthquake in 61 A. D.; but it was again rebuilt, and in the Middle Ages was named Chonæ.
COLOSSIANS, EPISTLE TO THE, a letter written to the Colossians by the Apostle Paul either from Rome or Cæsarea, at the same time that he wrote the epistles to the Ephesians and to Philemon. The epistle contains a summary of Christian doctrine, especially dwelling on the divine power and majesty of Christ, and a series of practical exhorta-
