Re: [Cameramakers] Light source for enlarging onto platinum-paladium and Kodak Azo papers
There is a second reason for wanting a shutter, namely, certain (many) kinds of discharge lamps greatly dislike being turned on and off very often. The lifetime can be drastically shortened. Needing a ballast and a lot of UV strongly suggest these are discharge lamps. It is worth checking the manufacturer's specs on this detail. Because the bulbs are fairly expensive this factor may influence your choice of lamp type, or at least your mode of operation (perhaps you will turn it on for the planned working period and depend solely on a shutter for control.) Bob PS Don't forget the power requirements if this is for home use. You can rarely take 10 kW out of the basement socket (that is enough power for a sauna and more than enough for the kitchen oven). In an industrial environment this will be less of a problem. At 16:37 01.02.03 -0800, you wrote: Thanks John, I appreciate all of the information on the El Nikor transmission capabilities. I will look forward to the layout of the bulbs in your lampsource. I have located a source on the east coast that makes lamps for UV curing and they have the capability to target a given UV range. They indicate a wattage output of 300 per inch of arc length. So a couple of 6 inch lamps should kick the output to something on the order of 3600 watts. They indicate that they will sell these in less then ten lots and they appear to be on the order of a hundred and change for each lamp. I have also located a ballast source that produces a variable ballast that achieves it's variance through varying the frequency of the voltage. The problem is that they indicate 450 watts as the upper limits of their ballast. I may need to go with a conventional ballast(s) as that problem is still not resolved. I am presently using a Saunders 4550 XLG as the enlarger for my 4X5 negatives and that has a 250 watt lamp. So I would think that the wattage that I am looking at should work for Azo at least. I do have an older Omega D2 that I will probably work with initially on this project. The problem that still exists so far as I am looking at it is that these lamps need a stabilization period to achieve consistant light output after strike. So it would seem that a shutter of some type may need to be incorporated in the light path. I think that possibly replacing the pneumatic actuator on a Packard shutter with an electrical solonoid would work for the shutter. The problem is that an potential vibration of the solonoid strike would need to be dampened. If you come up with other considerations that I am not addressing, please communicate those to me. Again, I will appreciate your light source configuration and reflector arrangement if one exists. Thanks again for your input. Regards, Donald Miller John Cremati [EMAIL PROTECTED] wrote: Donald, Here are some of the treads on the discussion of UV transmission thru El- Nikor glass from the Alternative Photo list.. I hope this will help... Please keep me informed of your progress as I am extremely interested. I kind of dropped the ball after getting this information and have still not hooked up my enlarger.. I will measure the spacing on the pulsed xenon bulbs.. I believe there were four in parrell close to a ground glass for diffusing and then there were two longer more powerful tubes .. crossing behind the 4 that were perpendicular forming a checker pattern. ... I do not think that these bulbs were on for any length of time as they were intended to expose ortho film which I believe has a ASA rating of about 5 or so and at 10,500 watts , that would not take long.. . I think the infrared will be a problem on long exposures... I was considering rigging some sort of Air conditioning system for the film chamber as I do not know if the fan will be enough... The enlarger will handle up to 11x14 negatives and has a 30x40 vacuumed frame for the enlargements .. .It is 10 feet tall and weighs 3000 pounds..(.This is probably the main reason that I have not hooked it up yet..) John Cremati .. Scientific graphics supply catalog that all Nikon El Nikor Enlarging Lenses were made of a special optical glass to allow passing of UV waves between 350 and 450 nm.. I have also read of Sun enlargers utilizing sunlight as the light source thru a lens to enlarge during the turn of the century in the book Keepers of Light ... Bit lefthanded! If you compare BK7 and UBK7 at 350nm, the difference ... Here's some interesting information I picked up from a Nikon Catalog about their enlarging lenses: EL-Nikkor enlarging lenses are corrected for chromatic aberration beyond the visible spectrum into near ultraviolet wavelengths -- wavelengths to which photographic papers are particularly sensitive. Through the use of special optical glass and matching optical coatings, EL-Nikkor lenses are designed for ultraviolet transmission in the 350 to
Re: [Cameramakers] Light source for enlarging onto platinum-paladium and Kodak Azo papers
Certainly if the material has appreciable sensitivity in the visible range the user would be advised to put as much light as possible in this range, where the optics are properly corrected. Bob At 01:04 02.02.03 +, you wrote: Aren't there other issues concerning the image quality that haven't been addressed? I can think of: (1) The enlarging lens must not only have the ability to transmit the UV radiations which are to expose the paper, it must have the ability to form a high quality, well-focused image in the wavelength range which is relevant. (2) If the photosensitive paper has any appreciable sensitivity to wavelengths outside the UV range, for example to wavelengths in the visible range, then the enlarging lens must bring these other wavelengths to the same focus as the UV or else they must be excluded from the illumination. RKS _ Help STOP SPAM with the new MSN 8 and get 2 months FREE* http://join.msn.com/?page=features/junkmail ___ Cameramakers mailing list [EMAIL PROTECTED] http://rmp.opusis.com/mailman/listinfo/cameramakers ___ Cameramakers mailing list [EMAIL PROTECTED] http://rmp.opusis.com/mailman/listinfo/cameramakers
Re: [Cameramakers] Light source for enlarging onto platinum-paladium and Kodak Azo papers
I know that the famous Fresson studio in France had set up a Enlarger for their secret process which would need a great deal of UV... I believe that they discuss the camera on their site... Click on the English for the Enlgish translation... JC http://photography.about.com/gi/dynamic/offsite.htm?site=http%3A%2F%2Fwww.atelier-fresson.com%2F
Re: [Cameramakers] Light source for enlarging onto platinum-paladium and Kodak Azo papers
Hi Donald , I also know in the silk screen industry that they have projection systems where they eliminate the large negatives used to contact print , and enlarge right on the coated silk screen...I have seen just one of these cameras in a old silk screen catalog but have never tried to research it any further.. The silk screen process requires a great deal of UV light as well .. I know that Ulano ( a mfg of silk screen emulsions ) sell a faster emulsion for the sole purpose of silk screen projection systems I do not know if the lenses used on these cameras are quartz or EL Nikkors... I have heard ( not verified ) that these cameras sell for $50,000 .. I have several high output UV lights intended for the silk screen industry . One at 1000 watts, 2000watts, 5000 watts and then the 10,500watt pulsed xenon ... I was intending to experiment on temperatures at the film plane as well as the enlargement plane once I got the camera set up as I feel this is going to be my biggest obstacle .. The process I am most interested in is Carbon Printing which I believe possibly exceeds platinum as the most beautiful process there is ( only does not have the expense of platinum plus offers a noticeable high relief quality that is found in no other process)The Fresson Process , although secret , is believed to be a form of a carbon printing process. The problem with Carbon is that it will be very temperature sensitive due to the large amount of gelatin used ... . I was thinking of rigging a series of water cooled tubing to the vacuum frame on the enlarger and piping it to a photographic chiller that I have.. ... Another idea is that I would also wash the vacuum frame with the breeze of a small air conditioner.. And refrigerate the blower air that cools the film in the light head... I will photograph the light head on the camera and send pictures off list if you want me to .. Regards, John Cremati ___ Cameramakers mailing list [EMAIL PROTECTED] http://rmp.opusis.com/mailman/listinfo/cameramakers
Re: [Cameramakers] Light source for enlarging onto platinum-paladium and Kodak Azo papers
Somebody was advertising a goerz gotar as a quartz a while ago on ebay. I don't know if it actually is a quartz lens, or if the seller was mis-informed. A quick google search didn't turn up much. Gotars aren't super rare and usually sell for under $100. John -- http://www.enteric.org snip These enlarging lenses don't have the spectral transmission of a true UV quarts lens, but then again they don't cost $3000 US dollars like Nikon's quartz lens ___ Cameramakers mailing list [EMAIL PROTECTED] http://rmp.opusis.com/mailman/listinfo/cameramakers
Re: [Cameramakers] Light source for enlarging onto platinum-paladium and Kodak Azo papers
The heat from a 5000 watt mercury lamp is basically not a factor on a short exposure. I would imagine (even though I haven't contact printed yet), that your exposures would be under a minute with a 5k lamp. I have been in the silk screen industry for 20 years, the shop I work in now has a 5k unit. Our exposures are from 2 minutes up. The distance is approximately 4 feet to the vertical table. Back in the old days we used a carbon arc lamp, love that old ozone smell!!! There are many companies making fast emulsions. The problem is the type. There are diazo and photopolymer emulsions. The latter needs a different spectrum lamp or it will never expose. The cameras you mentioned?? We use Barco laser created positives on acetate, taped to a screen and exposed in the vacuum frame. I tried coating some paper at work with emulsion and exposing it. The screen emulsion doesn't work unless the substrate is porous. Uncoated paper worked the best. I was using a 135 line Offset negative for the contact printing Meant to try more but... - Original Message - From: John Cremati [EMAIL PROTECTED] To: [EMAIL PROTECTED] Sent: Sunday, February 02, 2003 9:30 AM Subject: Re: [Cameramakers] Light source for enlarging onto platinum-paladium and Kodak Azo papers Hi Donald , I also know in the silk screen industry that they have projection systems where they eliminate the large negatives used to contact print , and enlarge right on the coated silk screen...I have seen just one of these cameras in a old silk screen catalog but have never tried to research it any further.. The silk screen process requires a great deal of UV light as well .. I know that Ulano ( a mfg of silk screen emulsions ) sell a faster emulsion for the sole purpose of silk screen projection systems I do not know if the lenses used on these cameras are quartz or EL Nikkors... I have heard ( not verified ) that these cameras sell for $50,000 .. I have several high output UV lights intended for the silk screen industry . One at 1000 watts, 2000watts, 5000 watts and then the 10,500watt pulsed xenon ... I was intending to experiment on temperatures at the film plane as well as the enlargement plane once I got the camera set up as I feel this is going to be my biggest obstacle .. The process I am most interested in is Carbon Printing which I believe possibly exceeds platinum as the most beautiful process there is ( only does not have the expense of platinum plus offers a noticeable high relief quality that is found in no other process)The Fresson Process , although secret , is believed to be a form of a carbon printing process. The problem with Carbon is that it will be very temperature sensitive due to the large amount of gelatin used ... . I was thinking of rigging a series of water cooled tubing to the vacuum frame on the enlarger and piping it to a photographic chiller that I have.. ... Another idea is that I would also wash the vacuum frame with the breeze of a small air conditioner.. And refrigerate the blower air that cools the film in the light head... I will photograph the light head on the camera and send pictures off list if you want me to .. Regards, John Cremati ___ Cameramakers mailing list [EMAIL PROTECTED] http://rmp.opusis.com/mailman/listinfo/cameramakers ___ Cameramakers mailing list [EMAIL PROTECTED] http://rmp.opusis.com/mailman/listinfo/cameramakers
Re: [Cameramakers] Light source for enlarging onto platinum-paladium and Kodak Azo papers
John Cremati [EMAIL PROTECTED] wrote: Hi Donald ,I also know in the silk screen industry that they have projectionsystems where they eliminate the large negatives used to contact print ,and enlarge right on the coated silk screen...I have seen just one ofthese cameras in a old silk screen catalog but have never tried to researchit any further.. The silk screen process requires a great deal of UV lightas well .. I know that Ulano ( a mfg of silk screen emulsions ) sell afaster emulsion for the sole purpose of silk screen projection systemsI do not know if the lenses used on these cameras are quartz or ELNikkors... I have heard ( not verified ) that these cameras sell for $50,000..I have several high output UV lights intended for the silk screenindustry . One at 1000 watts, 2000watts, 5000 watts and then the10,500watt pulsed xenon ... I was intending to experim! ent on temperatures atthe film plane as well as the enlargement plane once I got the camera setup as I feel this is going to be my biggest obstacle ..The process I am most interested in is Carbon Printing which Ibelieve possibly exceeds platinum as the most beautiful process there is( only does not have the expense of platinum plus offers a noticeable highrelief quality that is found in no other process)The Fresson Process ,although secret , is believed to be a form of a carbon printingprocess. The problem with Carbon is that it will be very temperaturesensitive due to the large amount of gelatin used ... . I was thinking ofrigging a series of water cooled tubing to the vacuum frame on theenlarger and piping it to a photographic chiller that I have.. ... Anotheridea is that I would also wash the vacuum frame with the breeze of asmall air conditioner.. And refrigerate the blower air that cools the filmin the light he! ad...I will photograph the light head on the camera and send pictures offlist if you want me to ..Regards,John Cremati___Cameramakers mailing list[EMAIL PROTECTED]http://rmp.opusis.com/mailman/listinfo/cameramakers Hello John, Yes if you have the opportunity to photograph the light head that would be great. My email is [EMAIL PROTECTED]. Thanks again for all of the information. Regards, Donald Miller
[Cameramakers] Light source for enlarging onto platinum-paladium and Kodak Azo papers
I am working on development of a light source to allow enlarging of images onto pt-pd and Azo papers. These papers need a light source in the upper UV band (350-475 nm). The other consideration are that these emulsions are markedly slower then conventional enlarging papers. I have two immediate concerns those being: 1.UV is largely invisible and this presents the problem of focusing the image on the easel. I could incorporate a conventional focusing light. If I do so will I experience focus shift when I switch to the UV lighting? Furthermore, will UV reflect in the same manner as visible light? I ask this because the light source will be diffusion to eliminate the cost of building condensors or buying a condensor enlarger since I already have three diffusion enlargers. 2. Will UV transmit through a conventional multicoated enlarger lens? I have an el-nikor 150 as my primary lens. I also have an older Schneider companon 135 mm which I think is uncoated. My Rodenstock medium format lenses are all coated. Any information or insight that you may provide will be greatly appreciated.
Re: [Cameramakers] Light source for enlarging onto platinum-paladium and Kodak Azo papers
Aside from the glass issue, unless you've got a lot of time and a cement column for your enlarger it won't work. With many UV bulbs 1"-2" from the Pt/Pd paper, the exposuers take minutes. However, I have known people to enlarge to Azo: 2-1/4 negs to 9" prints, and that seemed to work. The exposures will be long. Andy DONALD MILLER [EMAIL PROTECTED] wrote: I am working on development of a light source to allow enlarging of images onto pt-pd and Azo papers. These papers need a light source in the upper UV band (350-475 nm). The other consideration are that these emulsions are markedly slower then conventional enlarging papers. I have two immediate concerns those being: 1.UV is largely invisible and this presents the problem of focusing the image on the easel. I could incorporate a conventional focusing light. If I do so will I experience focus shift when I switch to the UV lighting? Furthermore, will UV reflect in the same manner as visible light? I ask this because the light source will be diffusion to eliminate the cost of building condensors or buying a condensor enlarger since I already have three diffusion enlargers. 2. Will UV transmit through a conventional multicoated enlarger lens? I have an el-nikor 150 as my primary lens. I also have an older Schneider companon 135 mm which I think is uncoated. My Rodenstock medium format lenses are all coated. Any information or insight that you may provide will be greatly appreciated. Do you Yahoo!? Yahoo! Mail Plus - Powerful. Affordable. Sign up now
Re: [Cameramakers] Light source for enlarging onto platinum-paladium and Kodak Azo papers
Thanks for your input everyone. I did speak with the people at Durst Pro yesterday and they are bringing to market in March a 5X7 enlarger that will be capable of enlarging both pt-pd and azo. The light source is primarily UV and is only suitable for the emulsions that I have listed. The cost of the enlarger will be $5,500. I was just thinking that if the technology is there that a light source for my existing enlarging systems would be something to look into. Durst already has and markets their 8X10 enlarger with a 5000 watt light source for enlarging conventional paper and azo. This enlarger goes out the door at $12,000 and the light source alone is $5,500. This enlarger is not suitable for pt-pd, however, since it has a different lamp in it. Andy Buck [EMAIL PROTECTED] wrote: Aside from the glass issue, unless you've got a lot of time and a cement column for your enlarger it won't work. With many UV bulbs 1"-2" from the Pt/Pd paper, the exposuers take minutes. However, I have known people to enlarge to Azo: 2-1/4 negs to 9" prints, and that seemed to work. The exposures will be long. Andy DONALD MILLER [EMAIL PROTECTED] wrote: I am working on development of a light source to allow enlarging of images onto pt-pd and Azo papers. These papers need a light source in the upper UV band (350-475 nm). The other consideration are that these emulsions are markedly slower then conventional enlarging papers. I have two immediate concerns those being: 1.UV is largely invisible and this presents the problem of focusing the image on the easel. I could incorporate a conventional focusing light. If I do so will I experience focus shift when I switch to the UV lighting? Furthermore, will UV reflect in the same manner as visible light? I ask this because the light source will be diffusion to eliminate the cost of building condensors or buying a condensor enlarger since I already have three diffusion enlargers. 2. Will UV transmit through a conventional multicoated enlarger lens? I have an el-nikor 150 as my primary lens. I also have an older Schneider companon 135 mm which I think is uncoated. My Rodenstock medium format lenses are all coated. Any information or insight that you may provide will be greatly appreciated. Do you Yahoo!?Yahoo! Mail Plus - Powerful. Affordable. Sign up now
Re: [Cameramakers] Light source for enlarging onto platinum-paladium and Kodak Azo papers
Hi Donald, The El Nikors will pass the UV light in the necessary range... other lenses will not.. .. There are several threads concerning this on The Alternative Photo list...The El Nikors use a special glass that does not filter UV like the others... We went as far as putting the lens on a UV spectrometer to see what the readings were along with a few other lenses and the only one that would pass the nessisary band width was the El Nikor... ... The information will be on the threads.. I have a old color separation camera with a 10,500 watt pulsed xenon light head on it... It has a 1 hp blower to keep things cool I was going it mount a 240mm El Nikor on this enlarger for the purpose of enlarging directly to make carbon prints.. .. . Also for glass film carriers here is some specs on Shott glass...( this may even be the glass that is used in the El-Nikors... John Cremati For those who are really interested in the exact physical and chemical properties of a sheet of glass with a high UV transmission : 0% at 280 nm 14% at 300 nm 65% at 320 nm 85% at 340 nm 90% from 360 nm and higher. thickness 2.0 mm you can e-mail to [EMAIL PROTECTED] and ask him for the specifications of Schott B270 superwite crown glass.He will send you a large attachment (~800 kB) to his answer. The internet address of an U.S. supplier is http://www.howardglass.com/B270.html Erich - Original Message - From: Gene Johnson To: [EMAIL PROTECTED] Sent: Saturday, February 01, 2003 10:15 AM Subject: Re: [Cameramakers] Light source for enlarging onto platinum-paladium and Kodak Azo papers If I remember right, UV doesn't like to pass through GLASS. Gene - Original Message - From: DONALD MILLER To: [EMAIL PROTECTED] Sent: Saturday, February 01, 2003 6:39 AM Subject: [Cameramakers] Light source for enlarging onto platinum-paladium and Kodak Azo papers I am working on development of a light source to allow enlarging of images onto pt-pd and Azo papers. These papers need a light source in the upper UV band (350-475 nm). The other consideration are that these emulsions are markedly slower then conventional enlarging papers. I have two immediate concerns those being: 1.UV is largely invisible and this presents the problem of focusing the image on the easel. I could incorporate a conventional focusing light. If I do so will I experience focus shift when I switch to the UV lighting? Furthermore, will UV reflect in the same manner as visible light? I ask this because the light source will be diffusion to eliminate the cost of building condensors or buying a condensor enlarger since I already have three diffusion enlargers. 2. Will UV transmit through a conventional multicoated enlarger lens? I have an el-nikor 150 as my primary lens. I also have an older Schneider companon 135 mm which I think is uncoated. My Rodenstock medium format lenses are all coated. Any information or insight that you may provide will be greatly appreciated. ___ Cameramakers mailing list [EMAIL PROTECTED] http://rmp.opusis.com/mailman/listinfo/cameramakers
Re: [Cameramakers] Light source for enlarging onto platinum-paladium and Kodak Azo papers
It depends how far into the UV you go. Many glasses transmit a fair amount of near UV. Which wavelength is needed for this process? Bob At 07:15 01.02.03 -0800, you wrote: If I remember right, UV doesn't like to pass through GLASS. Gene - Original Message - From: DONALD MILLER To: [EMAIL PROTECTED] Sent: Saturday, February 01, 2003 6:39 AM Subject: [Cameramakers] Light source for enlarging onto platinum-paladium and Kodak Azo papers I am working on development of a light source to allow enlarging of images onto pt-pd and Azo papers. These papers need a light source in the upper UV band (350-475 nm). The other consideration are that these emulsions are markedly slower then conventional enlarging papers. I have two immediate concerns those being: 1.UV is largely invisible and this presents the problem of focusing the image on the easel. I could incorporate a conventional focusing light. If I do so will I experience focus shift when I switch to the UV lighting? Furthermore, will UV reflect in the same manner as visible light? I ask this because the light source will be diffusion to eliminate the cost of building condensors or buying a condensor enlarger since I already have three diffusion enlargers. 2. Will UV transmit through a conventional multicoated enlarger lens? I have an el-nikor 150 as my primary lens. I also have an older Schneider companon 135 mm which I think is uncoated. My Rodenstock medium format lenses are all coated. Any information or insight that you may provide will be greatly appreciated.
Re: [Cameramakers] Light source for enlarging onto platinum-paladium and Kodak Azo papers
Further comment, following my previous one! The below listed wavelengths do pass through many glasses. Focusing will be somewhat of a problem, though you might be able to something similar to what is do for IR photography; find the right shift of focus, do it in the visible and then make the shift before exposing. There is another way. You can find fluorescent screens emitting in the visible when bombarded in the UV. Such materials are actually rather common. Many kinds of paper do it because they are deliberately dyed to cause them to do so. It gives the paper a whiter appearance. Better might be some materials which are overbright because they are printed or painted with DAY-GLO colors. (However you spell that!) You would want to suppress the normal part of the light you are viewing so you can see the consequences of the UV light. This could be done with a filter, probably in the light source or between the lens and the paper. Bob At 06:39 01.02.03 -0800, you wrote: I am working on development of a light source to allow enlarging of images onto pt-pd and Azo papers. These papers need a light source in the upper UV band (350-475 nm). The other consideration are that these emulsions are markedly slower then conventional enlarging papers. I have two immediate concerns those being: 1.UV is largely invisible and this presents the problem of focusing the image on the easel. I could incorporate a conventional focusing light. If I do so will I experience focus shift when I switch to the UV lighting? Furthermore, will UV reflect in the same manner as visible light? I ask this because the light source will be diffusion to eliminate the cost of building condensors or buying a condensor enlarger since I already have three diffusion enlargers. 2. Will UV transmit through a conventional multicoated enlarger lens? I have an el-nikor 150 as my primary lens. I also have an older Schneider companon 135 mm which I think is uncoated. My Rodenstock medium format lenses are all coated. Any information or insight that you may provide will be greatly appreciated. ___ Cameramakers mailing list [EMAIL PROTECTED] http://rmp.opusis.com/mailman/listinfo/cameramakers
Re: [Cameramakers] Light source for enlarging onto platinum-paladium and Kodak Azo papers
The spectrum of UV that this would involve are in the 350-450 nm range. Robert Mueller [EMAIL PROTECTED] wrote: Further comment, following my previous one! The below listed wavelengths do pass through many glasses. Focusing will be somewhat of a problem, though you might be able to something similar to what is do for IR photography; find the right shift of focus, do it in the visible and then make the shift before exposing. There is another way. You can find fluorescent screens emitting in the visible when bombarded in the UV. Such materials are actually rather common. Many kinds of paper do it because they are deliberately dyed to cause them to do so. It gives the paper a whiter appearance. Better might be some materials which are "overbright" because they are printed or painted with DAY-GLO colors. (However you spell that!) You would want to suppress the normal part of the light you are viewing so you can see the consequences of the UV light. This could! be done with a filter, probably in the light source or between the lens and the paper.BobAt 06:39 01.02.03 -0800, you wrote:I am working on development of a light source to allow enlarging of images onto pt-pd and Azo papers. These papers need a light source in the upper UV band (350-475 nm). The other consideration are that these emulsions are markedly slower then conventional enlarging papers. I have two immediate concerns those being:1.UV is largely invisible and this presents the problem of focusing the image on the easel. I could incorporate a conventional focusing light. If I do so will I experience focus shift when I switch to the UV lighting? Furthermore, will UV reflect in the same manner as visible light? I ask this because the light source will be diffusion to eliminate the cost of building condensors or buying a condensor enlarg! er since I already have three diffusion enlargers.2. Will UV transmit through a conventional multicoated enlarger lens? I have an el-nikor 150 as my primary lens. I also have an older Schneider companon 135 mm which I think is uncoated. My Rodenstock medium format lenses are all coated.Any information or insight that you may provide will be greatly appreciated.___Cameramakers mailing list[EMAIL PROTECTED]http://rmp.opusis.com/mailman/listinfo/cameramakers
Re: [Cameramakers] Light source for enlarging onto platinum-paladium and Kodak Azo papers
Donald, Here are some of the treads on the discussion of UV transmission thru El- Nikor glass from the Alternative Photo list.. I hope this will help... Please keep me informed of your progress as I am extremely interested. I kind of dropped the ball after getting this information and have still not hooked up my enlarger.. I will measure the spacing on the pulsed xenon bulbs.. I believe there were four in parrell close to a ground glass for diffusing and then there were two longer more powerful tubes .. crossing behind the 4 that were perpendicular forming a checker pattern I do not think that these bulbs were on for any length of time as they were intended to expose ortho film which I believe has a ASA rating of about 5 or so andat 10,500 watts , that would not take long... I think the infrared will be a problem on long exposures... I was considering rigging some sort of Air conditioning system forthe film chamber as I do not know if the fan will be enough... The enlarger will handle up to 11x14 negatives and has a 30x40 vacuumed frame for the enlargements .. .It is 10 feet tall and weighs 3000 pounds..(.This is probably the main reason that I have not hooked it up yet..) John Cremati .. Scientific graphics supply catalog that all Nikon El Nikor Enlarging Lenses were made of a special optical glass to allow passing of UV waves between 350 and 450 nm.. I have also read of Sun enlargers utilizing sunlight as the light source thru a lens to enlarge during the turn of the century in the book "Keepers of Light "... Bit lefthanded! If you compare BK7 and UBK7 at 350nm, the difference ...Here's some interesting information I picked up from a Nikon Catalogabout their enlarging lenses:EL-Nikkor enlarging lenses are corrected for chromatic aberrationbeyond the visible spectrum into near ultraviolet wavelengths --wavelengths to which photographic papers are particularly sensitive. Through the use of special optical glass and matching opticalcoatings, EL-Nikkor lenses are designed for ultraviolet transmissionin the 350 to 450 nm range. This means EL-Nikkor enlarging lenses canbe used for color separation in addition to all other enlargingapplications. EL-Nikkor lenses are also front threaded to accept screwin accessories , and can be used for exceptional small-objectphotography when mounted on a bellows.These enlarging lenses don't have the spectral transmission of a trueUV quarts lens, but then again they don't cost $3000 US dollars likeNikon's quartz lens Folks: I put a relatively new El-Nikkor 210 lens in the path of my UV spectrophotometer today, and am happy to report that the lens passes pretty well all UV radiation above 350 nm. In Comparison, my Fuji 300mm LF lens began to cut UV at around 400 nm, and showed strong absorption by 380 nm. This makes sense, as plain old plate glass shows similar trends. Cheers, Ed Stander
Re: [Cameramakers] Light source for enlarging onto platinum-paladium and Kodak Azo papers
Thanks John, I appreciate all of the information on the El Nikor transmission capabilities. I will look forward to the layout of the bulbs in your lampsource. I have located a source on the east coast that makes lamps for UV curing and they have the capability to target a given UV range. They indicate a wattage output of 300 per inch of arc length. So a couple of 6 inch lamps should kick the output to something on the order of 3600 watts. They indicate that they will sell these in less then ten lots and they appear to be on the order of a hundred and change for each lamp. I have also located a ballast source that produces a variable ballast that achieves it's variance through varying the frequency of the voltage. The problem is that they indicate 450 watts as the upper limits of their ballast. I may need to go with a conventional ballast(s) as that problem is still not resolved. I am presently using a Saunders 4550 XLG as the enlarger for my 4X5 negatives and that has a 250 watt lamp. So I would think that the wattage that I am looking at should work for Azo at least. I do have an older Omega D2 that I will probably work with initially on this project. The problem that still exists so far as I am looking at it is that these lamps need a stabilization period to achieve consistant light output after strike. So it would seem that a shutter of some type may need to be incorporated in the light path. I think that possibly replacing the pneumatic actuator on a Packard shutter with an electrical solonoid would work for the shutter. The problem is that an potential vibration of the solonoid strike would need to be dampened. If you come up with other considerations that I am not addressing, please communicate those to me. Again, I will appreciate your light source configuration and reflector arrangement if one exists. Thanks again for your input. Regards, Donald Miller John Cremati [EMAIL PROTECTED] wrote: Donald, Here are some of the treads on the discussion of UV transmission thru El- Nikor glass from the Alternative Photo list.. I hope this will help... Please keep me informed of your progress as I am extremely interested. I kind of dropped the ball after getting this information and have still not hooked up my enlarger.. I will measure the spacing on the pulsed xenon bulbs.. I believe there were four in parrell close to a ground glass for diffusing and then there were two longer more powerful tubes .. crossing behind the 4 that were perpendicular forming a checker pattern I do not think that these bulbs were on for any length of time as they were intended to expose ortho film which I believe has a ASA rating of about 5 or so andat 10,500 watts , that would not take long... I think the infrared will be a problem on long exposures... I was considering rigging some sort of Air conditioning system forthe film chamber as I do not know if the fan will be enough... The enlarger will handle up to 11x14 negatives and has a 30x40 vacuumed frame for the enlargements .. .It is 10 feet tall and weighs 3000 pounds..(.This is probably the main reason that I have not hooked it up yet..) John Cremati .. Scientific graphics supply catalog that all Nikon El Nikor Enlarging Lenses were made of a special optical glass to allow passing of UV waves between 350 and 450 nm.. I have also read of Sun enlargers utilizing sunlight as the light source thru a lens to enlarge during the turn of the century in the book "Keepers of Light "... Bit lefthanded! If you compare BK7 and UBK7 at 350nm, the difference ...Here's some interesting information I picked up from a Nikon Catalogabout their enlarging lenses:EL-Nikkor enlarging lenses are corrected for chromatic aberrationbeyond the visible spectrum into near ultraviolet wavelengths --wavelengths to which photographic papers are particularly sensitive. Through the use of special optical glass and matching opticalcoatings, EL-Nikkor lenses are designed for ultraviolet transmissionin the 350 to 450! nm range. This means EL-Nikkor enlarging lenses canbe used for color separation in addition to all other enlargingapplications. EL-Nikkor lenses are also front threaded to accept screwin accessories , and can be used for exceptional small-objectphotography when mounted on a bellows.These enlarging lenses don't have the spectral transmission of a trueUV quarts lens, but then again they don't cost $3000 US dollars likeNikon's quartz lens Folks: I put a relatively new El-Nikkor 210 lens in the path of my UV spectrophotometer today, and am happy to report that the lens passes pretty well all UV radiation above 350 nm. In Comparison, my Fuji 300mm LF lens began to cut UV at around 400 nm, and showed strong absorption by 380 nm. This makes sense, as plain old plate glass shows similar trends. Cheers, Ed Stander
Re: [Cameramakers] Light source for enlarging onto platinum-paladium and Kodak Azo papers
Thanks for bringing those issues to bear. I think that you have a valid concern. However in looking at the spectral response on the Kodak Azo data sheet it does show a marked decrease at the 450-475 nm level. I do expose Azo (contact print) with the use of a 300 watt R40 flood. I do not have the spectral range of that lamp but it must carry some UV as part of its output. I do know that Durst Pro is bringing out a 5X7 enlarger in March that will be used only for purposes of Azo and Pt-Pd. I spoke with them yesterday and they stated that while they did not advertise a wattage output of their lightsource of that enlarger since being heavily UV in output that wattage did not directly apply. I do not know enough about light intensity measurement in the UV spectrum to understand why wattage would not be determiner. Their representative after stating wattage was not advertised did say that it would be the equivalent of a 1000 watt source. Obviously a enlarging lens would need to! focus that light onto either Pt-pd or Azo paper. If you have further knowledge about this that would be of benefit, I would certainly appreciate hearing from you about it. Thanks again. Regards, Donald Miller Robert Stoddard [EMAIL PROTECTED] wrote: Aren't there other issues concerning the image quality that haven't been addressed? I can think of:(1) The enlarging lens must not only have the ability to transmit the UV radiations which are to expose the paper, it must have the ability to form a high quality, well-focused image in the wavelength range which is relevant.(2) If the photosensitive paper has any appreciable sensitivity to wavelengths outside the UV range, for example to wavelengths in the visible range, then the enlarging lens must bring these other wavelengths to the same focus as the UV or else they must be excluded from the illumination.RKS_Help STOP SPAM with the new MSN 8 and get 2 months FREE* http://join.msn.com/?page=features/junkmail___Cameramak! ers mailing list[EMAIL PROTECTED]http://rmp.opusis.com/mailman/listinfo/cameramakers
