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Photo Forum / Film Photography / Darkroom / January 2005Black Spots on Print Pre-Soak? or Enlarger?
Can black spots on a print be caused by dirty elements in a condensor enlarger? It's either dirty element, or an air bubble. The thing is, I thought I'd try "pre-soaking" my negs in H2O before developing and I'm wondering if that was a bad idea. > Can black spots on a print be caused by dirty elements in a condensor > enlarger? It's either dirty element, or an air bubble. No, dirty and/or chipped condensers cause white spots. Little bubbles in the condenser glass don't do anything. Do you have little white pinholes in the negative that correspond to the black spots on the print? > The thing is, I thought I'd try "pre-soaking" my negs in H2O > before developing and I'm wondering if that was a bad idea. It shouldn't cause pinholes. The most common cause of pinholes is the use of a strong stop-bath. IME, it seems to happen more often in 120 film than 35 or LF. Try using a water rinse between developer and fix. If you have Spotone colors it is possible to 'spot' the negative. This will usually result in white spots in the print, but white spots are easier to remove with more spotting color than black spots, which have to be scraped/bleached first and then spotted.  SignatureNicholas O. Lindan, Cleveland, Ohio Consulting Engineer: Electronics; Informatics; Photonics. Remove spaces etc. to reply: n o lindan at net com dot com psst.. want to buy an f-stop timer? nolindan.com/da/fstop/ I've got a couple of pinholes in this roll of 35mm TMY. You know, I just mixed up a new batch of Stop bath. I bet that's it. Maybe I screwed-up the ratio. I could dump it and try again. It smell pretty strong down there today. thx. I'll probably resort to scanning to retouch, but a nice silver print would be preferred. Thx again. > > Can black spots on a print be caused by dirty elements in a condensor > > enlarger? It's either dirty element, or an air bubble. [quoted text clipped - 18 lines] > are easier to remove with more spotting color than black spots, which > have to be scraped/bleached first and then spotted. > I've got a couple of pinholes in this roll of 35mm TMY. > You know, I just [quoted text clipped - 5 lines] > but a nice silver > print would be preferred. Thx again. Its extremely unlikely that you got pin holes from stop bath. First of all, the outgassing blamed for pin holes takes place only with developers containing carbonates, very few packaged film developers contain carbonate, in fact I can't think of any, at least those suppled by major manufacturers. Borax and Metaborate do not release gas. Secondly, the amount of gas where it does form must be so large that it can't diffuse out of the emulsion. Also, the emulsion of T-Max films is partly composed of synthetics and is very hard, again making pin holes unlikely. Pin holes were a problem in the 1930's when many film developers contained carbonate and when emulsions were very much softer than they are now. What you are seeing is likely from dust. True pinholes are physical disruptions of the emulsion and are often visible when the surface is examined by reflected light through a strong magnifier. Unless they are very large they will hold back light, in the way that scratched do, producing a light spot rather than a dark spot. Unless you are using some very odd developer the problem is neither the stop bath or pin holes. Signature--- Richard Knoppow Los Angeles, CA, USA dickburk@ix.netcom.com > Pin holes were a problem in the 1930's when many film developers > contained carbonate and when emulsions were very much softer > than they are now. OK, make me feel young... I have a few rolls of 120 with pinholes. Admittedly it has only happened a few times, and it was Arista film, but the developer was HC-110 and the time frame was in the last five years. TTTT, I can't prove the cause: I was startled to see them, as in "I thought this problem went away in the 30's." Even prints don't squeal the way they did in the old days. I think I'll have grits for dinner and see if I can FDR on the Neutrodyne. SignatureNicholas O. Lindan, Cleveland, Ohio Consulting Engineer: Electronics; Informatics; Photonics. Remove spaces etc. to reply: n o lindan at net com dot com psst.. want to buy an f-stop timer? nolindan.com/da/fstop/ >> Pin holes were a problem in the 1930's when many film >> developers [quoted text clipped - 19 lines] > the > Neutrodyne. The pinholes in the Arista may have been due to coating problems at Ilford. Ilford had a period where they evidently were having major coating problems. The Neutrodyne is interesting. It was invented by Hazeltine and was a method of neutralizing inter-electrode coupling in vacuum tubes to prevent unwanted oscillation. This was a very important patent. It probably accounts for the license note on most radios of the period from the mid 1920's to early 1940's. RCA owned most of the early radio patents but had to license this one from Hazeltine Labs. My hearing (once "golden ear") isn't good enough to hear paper hissing even if it did it. Signature--- Richard Knoppow Los Angeles, CA, USA dickburk@ix.netcom.com > What you are seeing is likely from dust. True pinholes > are physical disruptions of the emulsion and are often [quoted text clipped - 4 lines] > Unless you are using some very odd developer the problem > is neither the stop bath or pin holes. It may very well be dust on the film as I do hand load re-useable plastic cassettes (35mm). Upon closer examination one of the specks was "thread like" in nature and not perfectly round. Recently I had just disassembled my condensor head and was thinking that maybe some dust had resettled on the elements after reassembly, but these spots were "in focus" if a condensor head is using a diffuse light source it's probably not my problem. Thx. I was also seeing what I thought was a weird pattern, reticulation? could stop cause that too? > > Can black spots on a print be caused by dirty elements in a condensor > > enlarger? It's either dirty element, or an air bubble. [quoted text clipped - 18 lines] > are easier to remove with more spotting color than black spots, which > have to be scraped/bleached first and then spotted. >I was also seeing what I thought was a weird pattern, >reticulation? could > stop cause that too? No, reticulation is a physical wrinkling of the emulsion. Its generally caused by very large temperature differences, several degrees at least. Its very hard to reticulate modern film because the emulsions are so hard, but it is possible. Older Tri-X was notorious be being vulnerable to reticulation, T-Max films are almost impossible to reticulate, they are designed for 100F processing like color films. Other causes of patterns on the negatives are incomplete fixing, and, if you travel, possibly x-ray exposure. As with true pin holes reticulation, being mechanical, will be visible as a wrinkling of the film surface under examination with a strong magnifier. Signature--- Richard Knoppow Los Angeles, CA, USA dickburk@ix.netcom.com > >I was also seeing what I thought was a weird pattern, > >reticulation? could [quoted text clipped - 13 lines] > will be visible as a wrinkling of the film surface under > examination with a strong magnifier. My fix is fresh. Could going from 68F water bath to 64F ambient room air cause problems? My darkroom is fully below grade and fairly dry (<40RH) and cool in the winter. >> >I was also seeing what I thought was a weird pattern, >> >reticulation? could [quoted text clipped - 25 lines] > fairly dry (<40RH) and > cool in the winter. No, I mean _really_ big temperature differences, like going from 68F fixer to 90F wash water. Even then only a few films will reticulate. T-Max, and many other films, have a certain amount of polymers replacing part of the gelatin. They also have much more effective hardening agents than were used prior to about 1940. About all that was available before that was Chrome alum, which is not used in modern emulsions. The melting temperature of 1930's emulsions was probably not much more than 80F and it would be very soft well below that. Modern color and some B&W emulsions are hard enough to withstand processing at 100F so are not much stressed by a few degrees variation in solution temperatures. Actually, getting modern film to reticulate as a special effect is not very easy. Signature--- Richard Knoppow Los Angeles, CA, USA dickburk@ix.netcom.com > Can black spots on a print be caused by dirty elements in > a condensor [quoted text clipped - 3 lines] > developing and I'm > wondering if that was a bad idea. If you are working with negatives blemishes in the glass will result in white spots on the print. White spots sound more like there was dust on the negative during exposure. Check the negatives for dust or hair marks. Of course, if you are enlarging from transparencies anything holding back light in printing will show up as dark. Presoaking won't help if the negatives had dust on them in the camera. Air bells on the negative, from air bubbles forming during development, also leave dark marks since development is held back inside the bubble. Presoaking help to eliminate air bells but, again, they aren't the problem here. Signature--- Richard Knoppow Los Angeles, CA, USA dickburk@ix.netcom.com > "Can black spots on a print be caused by ... " ... light, unimpeded, exposing the paper. Yes. Black spots on the paper are because the paper is exposed. I use a water stop or none at all and a neutral to slightly alkalin fix. I don't worry about gas being generated in the emulsion. Chemicals are not 100% pure. Dan What film? |
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