Photochromic printing
The Photochrom print is a surface printing method for reproducing halftones in screenless multi-color printing with the use of the light sensitivity of Syrian asphalt .
technology
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The technology was developed ready for the market in the 1880s by the Zurich lithographer Hans Jakob Schmid (1856–1924) at Photochrom Zurich ( Orell Füssli ). For nearly a hundred years, photochromic printing was the most effective screenless planographic printing process for producing high-quality color reproductions, and its heyday came before the First World War .
The term is a few decades older than the technology used today. As a combination of the Greek φωτός (photos = genitive of light ) and the Χρώμα (chroma color ) and it means nothing else than color light image. Although for decades manufacturers wanted to give the impression that photochromic printing was a type of color photography , photochromic printing is actually a flat printing process . The negative of a black and white photograph is exposed on a litho stone coated with an asphalt mixture . The asphalt used becomes harder when exposed. The unexposed, still soft asphalt is washed off with a solvent. The exposed areas are then etched and no longer take on any color. A plate is made for each color to be printed. Then the stone is colored with the respective color and the motif is printed in the different shades on top of each other on paper or cardboard.
The complicated process was registered for a patent in France and Austria-Hungary at the same time in 1888 , but details of the inventor or the use of the asphalt were kept secret for decades. Photochromic printing has remained one of the best quality printing processes to this day, but the process is now very expensive and is only rarely used and for special prints.
See also
literature
- Bruno Weber: Around the world in photochrom. In: Max Mittler (ed.): Germany at the turn of the century. Zurich 1990, pp. 145–150 (reprinted by Museums Maur, Maur 2002, digitized version ).
- Sabine Arqué, Nathalie Boulouch, John Vincent Jezierski, Bruno Weber (eds.): Voyage en couleur. Photochromy 1876–1914 . Eyrolles et al., Paris 2009, ISBN 978-2-212-54270-7 (exhibition catalog with numerous illustrations and articles in German, French and English).
- Agnès Couzy (Ed.): Alpes Alpi Alps Alps . Photoglob et al., Zurich et al. 2007, ISBN 978-2-916231-07-5 (large-format color reproductions based on 100 years of hand-colored old black and white photos from the Photoglob archive).
- Peter Kunz: The photochromic print from the litho stone. Instructions and two original photochromic prints. With a conversation about photochromic and a glossary of technical terms . Edition Gilde Gutenberg, Küsnacht et al. 2006, ISBN 3-9523176-0-8 .
- Adrian Scherrer (Ed.): Schweiz = Suisse = Svizzera = Switzerland. 1889-1911 . Photoglob, Zurich 2009, ISBN 978-3-905873-05-4 (large-format color reproductions based on 100-year-old black and white photographs from the considerable archive of Photoglob AG in Zurich).
- Daniela Wegmann, Marc Walter, Sabine Arqué: PZ Photoglob Zurich - 125 years of Photochrom innovation . Ed .: Daniela Wegmann, Marc Walter, Sabine Arqué. Photoglob et al., Zurich et al. 2014, ISBN 978-3-905873-37-5 (The development of Photochrom products in the Belle Epoque around the world. From the first Photochroms, the formats and the various societies.).
Web links
- Digitized photochromic prints in the catalog of the Zurich Central Library (with 10,000 prints one of the world's largest collections)
- Photochrom collection of the Library of Congress , Washington
- Photochrom (English)
Individual evidence
- ↑ Peter Kunz: The photochromic print from the litho stone. 2006, pp. 20-36.