Benrido’s collotype technique combines digital imaging, photochemical processing, and pigment printmaking to produce remarkably rich, finely detailed images of the highest quality.
Collotypes are printed from plates prepared using a photochemical process. First, a glass plate is coated with bichromated gelatin, dried, and exposed to light under a negative. Then the plate is washed, causing the gelatin to swell and harden in proportion to the degree of exposure. As it hardens, the gelatin reticulates into the collotype’s hallmark pattern of microscopic wrinkles. This extremely fine natural reticulation renders the photographic image in continuous tones, distinguishing collotypes from prints made using today’s typical halftone processes. Continuous tone images like collotypes may display a practically infinite range of tonal values to reproduce extremely fine detail.
Collotypes are made by applying pigmented oil-based ink to paper or other media using a lithographic printing process. Such a process depends on the mutual repulsion of water and oil: the hardened areas of the plate accept ink in the shadow areas, while the unhardened gelatin repels ink in the highlights. Hand- operated presses transfer the pigment ink from plate to paper, where it bonds to the surface to produce remarkably dense shadow tones. Because each ink color is mixed to match the artist’s specifications, the Benrido printers can produce hues that are impossible to achieve using standard CMYK printing.
Benrido is the world’s only producer of full-color collotype prints. Collotypes may produce color in a variety of ways. For many years the process has been used to combine spot colors for a graphic effect similar to that of woodblock printing. More recently, the Benrido Atelier has developed a method of using color separations to produce full-color photographic collotypes. The full-color collotype printing technique may also be applied to produce subtly colored duotone, tritone or quadtone images, as multiple layers of ink may be combined.
Benrido provides today’s artists with a unique printing process that combines time-tested artisanship with the newest technology. As increasing numbers of photographers shoot and edit digitally, the Benrido printers now print collotypes from digital files. Prepress technicians output digital negatives to acetate film that is used to produce collotype plates for printing. Because negatives are produced from digital files, artists can easily send their images electronically to Benrido from anywhere in the world.