Color separations are used by major printing companies to reproduce the color images inside magazines, books, brochures, etc. Typical color separations consist of four colors: cyan, magenta, yellow, and black, or CMYK for short. However, large printing companies may use more if a particular color needs to be exact, such as a company color. By printing these four colors, one top of each other, one can create the illusion of a full-color photograph, when in reality, only four colors are shown.
Color separations used to be performed in the darkroom, using expensive and tedious processes. Today, with the technology of computers, scanners, laser printers, and Adobe PhotoShop, one can create a CMYK separation with relatively little time spent in the darkroom, compared to a few years ago.
When a color separations are created in the darkroom from a color photograph, printers use colored filters of CMYK, and halftone screens. Color filters are used to ‘separate’ the colors of the photograph into the CMYK colors. Halftone screens contain vignetted dots, which are dots that vary in darkness from the center out, darker to lighter, respectively. A common, decent quality, halftone screen contains 53 lines of vignetted dots per inch. When making a color separation in the darkroom, a printer has to set the angles of the dots for each CMYK separation at a particular angle in order to avoid a moire pattern (pronounced: mor - ray). This is a phenomen that more-or-less ‘magnifies’ the vignetted dots so it appears that there are large vignetted dots across the whole picture, thus creating a bad quality image. So the screen angles, in degrees, are as follows: Cyan - 45, Magenta - 75, Yellow- 90, and Black - 105.
However, this tedious process can by side-stepped with using Adobe PhotoShop. For example, the photograph is scanned, manipulated, and printed as four separate separations of differing levels of black and white, which represent the different intensities of CMYK for each separation (very much like if this color document were to be printed in black and white). These images are developed with a process camera onto lith film (a transparency-like film) to make a halfone negative, then the rest of the process is exactly the same for the manual and electonic methods.
Once the halftone negatives have been printed, then a color-key proof is made for each color. A ‘color-key’ is another transparency-like film that, instead of being black, like lith film, is almost any color you want, including the four colors of CMYK. This is a film that is used for proofing or previewing a color separation before it is sent through a large press run. So, each CMYK negative is developed with its respective color key material and then all four are laid on top of each other, lined up, thus finishing the process. The final product should be similar to the original color photograph that the printer started with.
Color separations used to be performed in the darkroom, using expensive and tedious processes. Today, with the technology of computers, scanners, laser printers, and Adobe PhotoShop, one can create a CMYK separation with relatively little time spent in the darkroom, compared to a few years ago.
When a color separations are created in the darkroom from a color photograph, printers use colored filters of CMYK, and halftone screens. Color filters are used to ‘separate’ the colors of the photograph into the CMYK colors. Halftone screens contain vignetted dots, which are dots that vary in darkness from the center out, darker to lighter, respectively. A common, decent quality, halftone screen contains 53 lines of vignetted dots per inch. When making a color separation in the darkroom, a printer has to set the angles of the dots for each CMYK separation at a particular angle in order to avoid a moire pattern (pronounced: mor - ray). This is a phenomen that more-or-less ‘magnifies’ the vignetted dots so it appears that there are large vignetted dots across the whole picture, thus creating a bad quality image. So the screen angles, in degrees, are as follows: Cyan - 45, Magenta - 75, Yellow- 90, and Black - 105.
However, this tedious process can by side-stepped with using Adobe PhotoShop. For example, the photograph is scanned, manipulated, and printed as four separate separations of differing levels of black and white, which represent the different intensities of CMYK for each separation (very much like if this color document were to be printed in black and white). These images are developed with a process camera onto lith film (a transparency-like film) to make a halfone negative, then the rest of the process is exactly the same for the manual and electonic methods.
Once the halftone negatives have been printed, then a color-key proof is made for each color. A ‘color-key’ is another transparency-like film that, instead of being black, like lith film, is almost any color you want, including the four colors of CMYK. This is a film that is used for proofing or previewing a color separation before it is sent through a large press run. So, each CMYK negative is developed with its respective color key material and then all four are laid on top of each other, lined up, thus finishing the process. The final product should be similar to the original color photograph that the printer started with.
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