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#1
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A positive form negative
piterengel wrote:
Hi everybody. I need for a certain work to obtain some positives from negatives. I can't treat all film with positive method, because a part of photos must remain negatives. I have a Contax Auto PC Bellow with slide duplicator, and a RTS II camera. Photos are taken using an Ilford Delta 100 film, developed in ID11. I want to use the same film for positives. My questions a The film to use for making positives on 35mm film is Eastman 5302 Fine Grain Release Positive. I bought some from Kodak in Toronto a few years ago for something like $CAN 17 for a 100 foot roll. Kodak Motion Imaging will probably still be willing to sell you a roll, it is also listed for sale at electron microscope suppliers because it is used by some models of electron microscopes as well as by the motion picture industry. The speed of 5302 is somewhere around 3 ASA, but this depends a bit on development and how much blue and violet are in the light source. Develop in Dektol 1:1 for 5 minutes. You can adjust contrast a little by playing around with different developers. The film looks like white plastic. It can be handled fairly freely under any safelight for B&W enlarging paper. You should have no trouble bulk loading it into 135 cartridges by hand. Peter. -- |
#2
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A positive form negative
"Peter Irwin" wrote in message ... piterengel wrote: Hi everybody. I need for a certain work to obtain some positives from negatives. I can't treat all film with positive method, because a part of photos must remain negatives. I have a Contax Auto PC Bellow with slide duplicator, and a RTS II camera. Photos are taken using an Ilford Delta 100 film, developed in ID11. I want to use the same film for positives. My questions a The film to use for making positives on 35mm film is Eastman 5302 Fine Grain Release Positive. I bought some from Kodak in Toronto a few years ago for something like $CAN 17 for a 100 foot roll. Kodak Motion Imaging will probably still be willing to sell you a roll, it is also listed for sale at electron microscope suppliers because it is used by some models of electron microscopes as well as by the motion picture industry. The speed of 5302 is somewhere around 3 ASA, but this depends a bit on development and how much blue and violet are in the light source. Develop in Dektol 1:1 for 5 minutes. You can adjust contrast a little by playing around with different developers. The film looks like white plastic. It can be handled fairly freely under any safelight for B&W enlarging paper. You should have no trouble bulk loading it into 135 cartridges by hand. Peter. -- The problem is that this film may now be available only in 1000 foot spools but do check. Kodak may still have a data sheet for it. The sheet gives development instructions for various degrees of contrast, all using readily available developers. While not many B&W movies are made now the film was also used for special effects masks and other purposes. The speed is comparable to fast enlarging paper and its handled about the same way. Because the spectral sensitivity is confined to the blue it can be handled under an OC safelight although I think Kodak recommends a red light. Processing is very much like RC printing paper. If you can obtain it economically its definitely the stuff to use. -- -- Richard Knoppow Los Angeles, CA, USA |
#3
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A positive form negative
Richard Knoppow wrote:
The problem is that this film may now be available only in 1000 foot spools but do check. I hadn't known that. The Jan 31 2008 Price Change Bulletin would seem to show 1000 feet rolls as a minimum quantity. That may not be a complete disaster though. 5302 is one of the cheapest films made, so I think that 1000 foot roll might be around $120. It also may still be possible to buy an 100 foot roll from a microscope specialty store for around $20. I bought 100 feet of 5360 from Ted Pella, since Kodak had a minimum order of 1000 feet of 5360. The PDF for 5302 is at: http://www.motion.kodak.com/motion/uploadedFiles/US_plugins_acrobat_en_motion_products_lab_h15302.p df Peter. -- |
#4
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A positive form negative
"piterengel" wrote in message ... On 31 Ago, 04:26, "Richard Knoppow" wrote: "Peter Irwin" wrote in message ... piterengel wrote: Hi everybody. I need for a certain work to obtain some positives from negatives. I can't treat all film with positive method, because a part of photos must remain negatives. I have aContaxAuto PC Bellow with slide duplicator, and a RTS II camera. Photos are taken using an Ilford Delta 100 film, developed in ID11. I want to use the same film for positives. My questions a The film to use for making positives on 35mm film is Eastman 5302 Fine Grain Release Positive. I bought some from Kodak in Toronto a few years ago for something like $CAN 17 for a 100 foot roll. Kodak Motion Imaging will probably still be willing to sell you a roll, it is also listed for sale at electron microscope suppliers because it is used by some models of electron microscopes as well as by the motion picture industry. The speed of 5302 is somewhere around 3 ASA, but this depends a bit on development and how much blue and violet are in the light source. Develop in Dektol 1:1 for 5 minutes. You can adjust contrast a little by playing around with different developers. The film looks like white plastic. It can be handled fairly freely under any safelight for B&W enlarging paper. You should have no trouble bulk loading it into 135 cartridges by hand. Peter. -- The problem is that this film may now be available only in 1000 foot spools but do check. Kodak may still have a data sheet for it. The sheet gives development instructions for various degrees of contrast, all using readily available developers. While not many B&W movies are made now the film was also used for special effects masks and other purposes. The speed is comparable to fast enlarging paper and its handled about the same way. Because the spectral sensitivity is confined to the blue it can be handled under an OC safelight although I think Kodak recommends a red light. Processing is very much like RC printing paper. If you can obtain it economically its definitely the stuff to use. -- -- Richard Knoppow Los Angeles, CA, USA After a bit of time I'm back with few news. I've tried to obtain positive from negative as follow. NEGATIVE I've used Ilford Delta 100 film developer in Perceptol full strength fo 15 mins. Subjects were macro images of iron dust modelled with a magnet. Camera: Contax RTS II, lens Zeiss Planar 60 f/2.8 Macro. Negatives are good, reach of details, a little bit dark but this is not a problem. POSITIVE Equipment: Contax auto bellows with slice copier tool, RTS II mounted and Planar 50 f/1.7 as lens. I've extended bellows for 50 mm to obtain 1:1 macro ratio. The lens was set on f/16, the minimum aperture available. I've used a TTL flash as light source (I've tried with a high power incandescend light source but results were worst). Film: Efke 25 developed in Rodinal 1+100, prebath of 1 min in water, than developer for 18 mins. This was a test film, for the final work I want to use Kodak Tech Pan filam (yes, I've few of them in my refrigerator...). Problems: I've noted, as said, taht it is better to work with flash light; but the most important problem is that the center of the pictire is in focus and edges are not. This is a very big problem for me. I've not the bellows instructions manual but I don't think I'm doing something wrong. Before using my precious Kodak TP film I hope somebody can help me. Thanks all P. This may be due to using the lens so far from its optimum distance. All lenses with fixed position elements can be optimized for only one distance and at others begin to pick up aberrations. One of these is curvature of field. In general, the faster the lens the worse the problem. If you can adapt an enlarger lens to the camera it will probably give you better results. but you really need a lens optimized for a distance suitable for unity magnification. You might get better results by contact printing. Leitz made a small contact printing device for making 35mm slides from negatives. Its called an eldia and I found one at a local sale for not much. -- -- Richard Knoppow Los Angeles, CA, USA |
#5
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A positive form negative
"piterengel" wrote
Contax auto bellows with slice copier tool, RTS II mounted and Planar 50 f/1.7 as lens ... problem is that the center of the pictire is in focus and edges are not. As Richard mentioned, try using an enlarging lens. To mount an enlarging lens on a bellows just cut a hole in a body cap and thread the lens into the cap and mount the cap on the bellows. -- Nicholas O. Lindan, Cleveland, Ohio Darkroom Automation: F-Stop Timers, Enlarging Meters http://www.darkroomautomation.com/da-main.htm n o lindan at ix dot netcom dot com |
#6
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A positive form negative
In article ,
piterengel wrote: Mr. Knoppow, as any other time you're right. The problem was lens. I've adapted Planar 60 Macro to slide copier, working at f/22. Results are very good. In the meanwhile I've ordered on eBay from England an adapter ring from M42 to Contax to be able to mount enlarger lens on bellows. Till now it is not arrived but surely I'll try with this too. This may work. But it is unduly complex. I would second Richard's suggestion of contact-printing the film. With a sufficiently dim light, even standard 25ASA film will work to make the positives. Simply cut lengths of the unexposed film to match the lengths of the cut strips of developed negative film, align them carefully, and place them in a standard glass-front, foam or rubber-backed contact printer, or, if you do not have a contact printing frame, use a heavy sheet of glass (1/4" or thicker) on top of the two pieces of film, on top of a clean, black surface. It will take a few tries to calibrate exposure but you can use normal development times and will achieve excelent results. And there will be no focus or sharpness problems -- guaranteed. Slide copiers exist really only to deal with the annoyance of copying already cut and mounted slides, which are too thick to be contact printed as I describe above with good results. -- Thor Lancelot Simon "Even experienced UNIX users occasionally enter rm *.* at the UNIX prompt only to realize too late that they have removed the wrong segment of the directory structure." - Microsoft WSS whitepaper |
#7
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A positive form negative
"piterengel" wrote in message ... On 24 Ott, 01:27, (Thor Lancelot Simon) wrote: In article , piterengel wrote: Very long previous thread snipped............... Today it is arrived the adapter ring I've described above. So I'll try with 50 mm enlarger lens first, then with contact print too. In this last acse, do you have an approximate idea on time of exposure? I think to place the column at least 10 in high with completely close diafragm of lens (f/22). so how long could be the exposition? or can I try to use an external exposimeter to determine this? Use an enlarger as your light source. You may have to put something in to cut down the light. Even a sheet of thin paper in the negative holder will work. Most exposure meters will not read low enough to be useful for this but you can get some idea of needed exposure by knowing that most variable contrast enlarging papers are around ISO-6 when used without a filter and around ISO-3 with a medium contrast filter. Find the exposure for a good print and divide that by the ratio of paper speed to film speed. Otherwise you will have to find the exposure by making a test strip, that is making several exposures about one stop apart (each double or half the last). You really only have to do this once to calibrate the setup. Also, I think it may be possible to use a SLR camera with a through the lens exposure meter to make the measurement by laying it under the enlarger and exposing for about 5 times the white light reading made with a clear negative (no image) in the enlarger. The reason for the clear negative is to account for the density of the support which is considerable for most 35mm negative films due to the anti-light-piping pigment in them. I suggested the Leitz Eldia contact printer before because I think they are not too difficult to find and are very convenient for this. They were originally meant to print onto non-color-sensitized slow film of the sort meant for making B&W motion picture prints. One of these films, Kodak Fine Grain Release Positive, is ideal but is now available only in 1000 foot spools. This film has about the same speed as fast enlarging paper is processed in print chemicals. Agfa and Ilford made similar films but I suspect they are long off the market. Slow, fine grain, pictorial film works fine but most 35mm negative films have a pigment in the support which can not be removed and makes the slides just a little darker than the clear support on the printing film. Not a real problem but you should be aware of it. For projection the positive needs to be rather contrasty compared to normal negative contrast. Most of the very slow fine grain films are inherently contrasty and its possible to get the necessary contrast and high shadow density with films like T-Max 100 by processing them is somewhat high contrast developers like Dektol. I think Kodak has some limited information on this use but don't know specifically where it is. All this makes the procedure look more complicated than it is. Positive slides for projection were the rule for many years before 35mm reversal films came on the market, hence the Eldia and similar devices. -- -- Richard Knoppow Los Angeles, CA, USA |
#8
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A positive form negative
In article ,
Richard Knoppow wrote: contrast filter. Find the exposure for a good print and divide that by the ratio of paper speed to film speed. That would be, of course, "the exposure for a good print of the same size as the lighted area cast by the enlarger set to cover the contact frame" -- the exposure with the enlarger column at the same height, basically. I'm sure Richard knows this but I got it wrong the first time I tried this process so I thought I should elucidate. Otherwise you will have to find the exposure by making a test strip, that is making several exposures about one stop apart (each double or half the last). You really only have to do this once to calibrate the setup. This is what I have always found simplest. Slow, fine grain, pictorial film works fine but most 35mm negative films have a pigment in the support which can not be removed and makes the slides just a little darker than the clear support on the printing film. Not a real problem but you should be aware of it. For projection the positive needs to be rather contrasty compared to normal negative contrast. Most of the very slow fine grain films are inherently contrasty and its possible to get the necessary contrast and high shadow density with films like T-Max 100 by processing them is somewhat high contrast developers like Dektol. Another option which occurs to me is to use Kodalith. Is it still sold in 35mm roll film? For the longest time, it was, but under a different (and strange) product name. It does not have a pigmented base, and if developed in a very dilute developer (HC110 dilution F works; POTA would probably work better) will in fact give negatives of slightly higher than standard contrast. It's also *very* slow, and can be handled under a dim red safelight. Perhaps it is almost ideal for this use. The disadvantage is that more work will be needed to calibrate exposure and development since Kodak's tables won't be helpful. What I did last time I needed nice snappy slides from copied small format negatives was develop normally and then intensify with very strong selenium toner (1:3). This gives a color change, which is not ideal, and is wasteful of the somewhat expensive toner, but I was in a hurry and it got the job done with the materials I had on hand, and I didn't have to recalibrate my development system for some oddball developer like Dektol 1:10. Chromium intensifier, if you can still get it, would probably work better. -- Thor Lancelot Simon "Even experienced UNIX users occasionally enter rm *.* at the UNIX prompt only to realize too late that they have removed the wrong segment of the directory structure." - Microsoft WSS whitepaper |
#9
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A positive form negative
"Thor Lancelot Simon" wrote in message ... In article , Richard Knoppow wrote: contrast filter. Find the exposure for a good print and divide that by the ratio of paper speed to film speed. That would be, of course, "the exposure for a good print of the same size as the lighted area cast by the enlarger set to cover the contact frame" -- the exposure with the enlarger column at the same height, basically. I'm sure Richard knows this but I got it wrong the first time I tried this process so I thought I should elucidate. Otherwise you will have to find the exposure by making a test strip, that is making several exposures about one stop apart (each double or half the last). You really only have to do this once to calibrate the setup. This is what I have always found simplest. Slow, fine grain, pictorial film works fine but most 35mm negative films have a pigment in the support which can not be removed and makes the slides just a little darker than the clear support on the printing film. Not a real problem but you should be aware of it. For projection the positive needs to be rather contrasty compared to normal negative contrast. Most of the very slow fine grain films are inherently contrasty and its possible to get the necessary contrast and high shadow density with films like T-Max 100 by processing them is somewhat high contrast developers like Dektol. Another option which occurs to me is to use Kodalith. Is it still sold in 35mm roll film? For the longest time, it was, but under a different (and strange) product name. It does not have a pigmented base, and if developed in a very dilute developer (HC110 dilution F works; POTA would probably work better) will in fact give negatives of slightly higher than standard contrast. It's also *very* slow, and can be handled under a dim red safelight. Perhaps it is almost ideal for this use. The disadvantage is that more work will be needed to calibrate exposure and development since Kodak's tables won't be helpful. What I did last time I needed nice snappy slides from copied small format negatives was develop normally and then intensify with very strong selenium toner (1:3). This gives a color change, which is not ideal, and is wasteful of the somewhat expensive toner, but I was in a hurry and it got the job done with the materials I had on hand, and I didn't have to recalibrate my development system for some oddball developer like Dektol 1:10. Chromium intensifier, if you can still get it, would probably work better. The exposure ratio I used is one Kodak recommended for calculating exposure when copying. Whte paper is placed on the easel and measured. The exposure is then multiplied by a factor of 5. Actually, this is the same as making the measurement with an 18% gray card. In the case of an enlarger the light measured is that light falling on the film so some correction is necessary. I like the idea of using lith film. By choice of developer the contrast might be made the same as positive printing films. Kodak Fine-Grain Release Positive used to be dirt cheap and came in 100 foot spools. No more but there may be FGRP available outdated. Because it is so slow the chances are it can be quite old without being fogged. Its ideal for making B&W slides from B&W negatives but won't work for color negatives because it is sensitive only to blue light. In fact, it can be handled under a red safelight. Some lith film is blue sensitive but panchromatic lith film has been made (maybe still?) and might be quite useful. -- -- Richard Knoppow Los Angeles, CA, USA |
#10
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A positive form negative
In article ,
Richard Knoppow wrote: I like the idea of using lith film. By choice of developer the contrast might be made the same as positive printing films. Kodak Fine-Grain Release Positive used to be dirt cheap and came in 100 foot spools. No more but there may be FGRP available outdated. Because it is so slow the chances are it can be quite old without being fogged. Its ideal for making B&W slides from B&W negatives but won't work for color negatives because it is sensitive only to blue light. In fact, it can be handled under a red safelight. Some lith film is blue sensitive but panchromatic lith film has been made (maybe still?) and might be quite useful. The 35mm Kodalith I remember was "Kodak Ektagraphic HC". It's been discontinued and I am not sure *any* Kodalith remains in production. Wow. -- Thor Lancelot Simon "Even experienced UNIX users occasionally enter rm *.* at the UNIX prompt only to realize too late that they have removed the wrong segment of the directory structure." - Microsoft WSS whitepaper |
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