[S-fotografie] 1. ESHPh - 2. Thread nella lista PhotoHistory
sara.filippin a gmail.com
Ven 27 Apr 2012 14:17:02 CEST
Scrivo alla lista relativamente a due temi diversi:
Ho visto oggi la pagina web della rivista PhotoResearcher,
curata dalla European Society for the History of Photography, fondata nel 1978, e che ha ora base a Vienna.
I numeri dall' 1 (1990) al 14 (2010) sono liberamente scaricabili - ad una prima e veloce esplorazione mi sembra molto seria -; dei successivi si può vedere l'indice e l'editoriale.
Non sapevo dell'esistenza né della rivista né della ESHPh, ma immagino che molti di noi invece ne sappiano qualcosa. Mi interesserebbe quindi avere le loro opinioni sull'attività e la conduzione di questa associazione. Qualcuno può dare qualche informazione?
Ho trovato interessante un recente thread nella lista PhotoHistory e mi permetto di condividerlo. So che alcuni di noi già ne conoscono i contenuti (nel caso scusate il doppione), ma ad altri potrebbe essere utile.
Lo riporto integralmente, dalla prima mail all'ultima, ovviamente cancellando i riferimenti personali. Ecco quanto è stato scritto:
Does anyone know when resin coated photographic papers (b/w or colour) were introduced? I am getting a number of different answers from those in the industry and just wondered if anyone had a reasonably accurate date?
I remember using them starting around 1975, but it seems to me that they were used several years earlier by consumer-level color photo labs.
Cibachrome was introduced in 1963 at Photokina.
Here's a site with patents for resin-coated photographic papers, the earliest listed is 1967:
I recall using some sort of resin-coated paper while serving in the US Army in 1969 and 1970. Also, I believe that cibachrome isn't really a resin coated surface by some form of polyester base rather than paper.
Assuming RC is defined as polyethylene layers coated on both sides of a paper support:
Resin-coated or RC supports were first used by Kodak in their Verifax donor material in the 1950s or early 1960s. The technology was borrowed from the packaging industry, where Kodak had their first RC supports manufactured.
An RC support consists of raw base material (paper) sandwiched between layers of extruded polyethylene. RC supports were introduced for Kodak color prints in 1968 and fiber-base prints were quickly discontinued. It is rare to see fiber-base prints after 1968, although it was still being made as late as 1971 as evidenced by a sample book from that year.
ca 1970 for Kodak B+W RC papers
Any earlier dates would be for patents or other materials with the same name, as there were no photographic printing papers made on RC supports prior to 1968.
There were waterproof supports for gelatin silver prints, sometimes referred to as RC supports in the 1940s and 50s, but we no longer refer to them as RC.
Agfa didn't convert to RC for their chromogenic papers until later in the 1970s, but I don't have an exact date on that.
Cibachrome, when it was introduced in 1963, was on pigmented tri-acetate, so again not an RC by my working definition.
Kodachrome prints (aka Minicolor or Kotavachrome) were introduced in 1941 and they were also on pigmented tri-acetate.
There are other examples of various waterproof or plastic papers, but none were RC.
There was also another paper. The only reference I have is very obtuse. The school I was taking photo classes at had a very large yellow sign in front of the Pako print dryer that read: NO RC or RD papers! I new RC was resin coated, I asked what RD meant and the best answer I got was "Some paper that was supposed to have the benefits of both fiber based and RC papers, but in fact had neither. Either that or it was a proto-RC paper that we've long forgotten about"
Having had a background in the graphic arts, working in London in the late 60s it is worth mentioning that the introduction of Estar-based film material radically alter the foundations upon which the photo-reprographic industries were based. For the first time it was possible to make 4 colour sets using film. Prior to the mid 1860s all colour separation work had to be done from negatives on a glass base. Up to that point film was not dimensionally stable. Kodak cine and still films from 1956 onward were Estar-based. Estar-based films were archival: polyethylene terephthalate (a polyester similar to DuPont's Mylar). Its introduction coincided with the development of Algraphy (aluminium photo-lithographic plates).
As a student I made friends with some of the employees (omissis) one of the leaders in the field. At the time they were still using the wet collodion plates for colour separation because of its stability and sharpness. In spite of the restrictions imposed on the workforce (by the management and the trade unions) I managed to sneak into the workshops and witnessed the coating of the glass sheets, by hand often, one-to-one (20 by 30 inch sheets for art reproductions). Not a very health environment in which to spend your working life.
Kodak's first official RC papers were introduced c.1973 or so, when I was in high school. But before that they made several water-resistant papers called 'Resisto' and 'Resisto Rapid', which to my then teenage-beginner eyes looked and acted very much like RC paper. Perhaps the Resisto papers were an outgrowth of graphic-arts practice-but that's just a guess.
Kodak Resisto and Resisto Rapid are listed in the paper section of the _Kodak Reference Handbook_ for 1946 but not in the second edition, dated 1943. The description of the
processing is the same as for RC papers. However, there is no information on what the paper support was treated with to make it water resistant. Resisto was a contact speed paper and Resisto Rapid an enlarging speed paper.
Its quite possible that similar paper was available earlier for special purposes such as rapid printing of aerial photos.
Cari saluti a tutti.
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