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oil immersion?
Sorry, but I don't know what to call it - the technique where one immerses the negative in a fluid in order to surpress dust. Pointers to information? |
#2
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oil immersion?
Check under "Carlwen" he
http://www.phototechmag.com/buying_drkroom.htm This information was published in 1998 so I don't know if it's still current. njb On Wed, 11 Feb 2004 18:53:02 -0600, (jjs) wrote: Sorry, but I don't know what to call it - the technique where one immerses the negative in a fluid in order to surpress dust. Pointers to information? |
#3
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oil immersion?
In article , Nacio Jan Brown
wrote: Check under "Carlwen" he http://www.phototechmag.com/buying_drkroom.htm This information was published in 1998 so I don't know if it's still current. njb Very helpful, thank you. It turns out they are currently listed, and by gosh, right here in my home state. |
#4
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oil immersion?
"jjs" wrote in message ... Sorry, but I don't know what to call it - the technique where one immerses the negative in a fluid in order to surpress dust. Pointers to information? Ctein wrote in _Post Exposure_ about using Edwal No-Scratch on the whole negative to reduce dust. If you have the book, his explanation was pretty convincing, but I haven't needed to do it yet. I wonder if the stuff will act as a dust magnet, however. PEC-12 removes it. Edwal's No-Scratch should be in every darkroom. I've always had a bottle next to the enlarger (replace when it begins to yellow). It smells like turpentine and in fact, I think that is what it is (was) made of. __________________________________________________ _____________________________ Posted Via Uncensored-News.Com - Accounts Starting At $6.95 - http://www.uncensored-news.com The Worlds Uncensored News Source |
#5
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oil immersion?
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#6
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oil immersion?
On Wednesday 11 February 2004 04:53 pm, jjs wrote:
Sorry, but I don't know what to call it - the technique where one immerses the negative in a fluid in order to surpress dust. Pointers to information? You're referring to an oil negative carrier, the primary advantage of which is the elimination of scratches on the negative. Any dust just floats off. Traditional oil carriers are VERY messy. It uses real oil, but a special type, that has the same index of refraction as the film base. The negative HAS to be cleaned after printing. Some time ago -- 20 years, IIRC, there was a company (in Texas???) that had come out with an "oil" that worked just as well as the traditional oil, but would evaporate from the negative, when set aside after printing and, thus, no cleaning was required. -- Stefan Patric |
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oil immersion?
Wet Gate Printing. Invented in the end of the 70s, early 80s for
printing release prints of movies. Actually wet gate printing has been around for the last 100 years. Some gates use oil and some others, a sort of dry cleaning fluid. In most motion picture work, they use 100 proof grain alcohol and true the motion picture industry started using it in the early 80's Larry |
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oil immersion?
The other "messy" part is that any dust that falls on the negative is going
to stick to the oil and you won't be able to blow it off. -- darkroommike ---------- "Stefan Patric" wrote in message news:e%7Xb.1296$Mf.1262@okepread04... On Wednesday 11 February 2004 04:53 pm, jjs wrote: Sorry, but I don't know what to call it - the technique where one immerses the negative in a fluid in order to surpress dust. Pointers to information? You're referring to an oil negative carrier, the primary advantage of which is the elimination of scratches on the negative. Any dust just floats off. Traditional oil carriers are VERY messy. It uses real oil, but a special type, that has the same index of refraction as the film base. The negative HAS to be cleaned after printing. Some time ago -- 20 years, IIRC, there was a company (in Texas???) that had come out with an "oil" that worked just as well as the traditional oil, but would evaporate from the negative, when set aside after printing and, thus, no cleaning was required. -- Stefan Patric |
#9
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oil immersion?
ObContEd:
Oil immersion has applications in imaging beyond scratch 'n dust. The oil allows a 50% increase in numerical aperture, with a corresponding increase in resolution with decreased diffraction. A little javap from Nikon shows the effect of immersion oil in a microscope: http://www.microscopyu.com/tutorials...ion/index.html To bad Nikon doesn't have a 'photographyu'. -- Nicholas O. Lindan, Cleveland, Ohio Consulting Engineer: Electronics; Informatics; Photonics. |
#10
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oil immersion?
"Nicholas O. Lindan" wrote in message ink.net... ObContEd: Oil immersion has applications in imaging beyond scratch 'n dust. The oil allows a 50% increase in numerical aperture, with a corresponding increase in resolution with decreased diffraction. A little javap from Nikon shows the effect of immersion oil in a microscope: http://www.microscopyu.com/tutorials...ion/index.html To bad Nikon doesn't have a 'photographyu'. -- Nicholas O. Lindan, Cleveland, Ohio Consulting Engineer: Electronics; Informatics; Photonics. Oil immersion for microscope objectives is a different thing from wet gate printing. The oil used has an index of refraction higher than air so the angle of incidence at the entrance pupil of the objectective can be larger. An actual oil is used. Wet gate printing uses an alcohol. The index of refraction is chosen to be near that of the support. So, the liquid fills in the scratches on the support with a material which does not diffract light at the scratches. There have been several solvents used in the past, most of which are now considered environmental hazards. 1,1,1,trichlorethane and perchlorethane were common for this application as well as film cleaning. Now very dry Isopropyl alcohol is used for both cleaning and wet gate printing. Because the liquid matches the support its most effective on scratches on the back of the film. It has little benefit for scratches in the emulsion. Emulsion scratches tend to disrupt the image anyway so even a liquid matching the index of the gelatin would be of limited benefit. -- --- Richard Knoppow Los Angeles, CA, USA |
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