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#11
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Dumb question processing 4x5
"Ken Hart" wrote
What if the base were tilted just a couple of degrees? Then the drum 'walks' off the roller - at least Jobo drums and a Unicolor base. I find I have to shim the base so the drum stays on top - or at the least to be sure it walks so the cap end rubs up against the base. I use the older style 4x5 Jobo reels (? clear spiral reels holding 6 sheets each) and do not have streaking problems when using them on a motor base (famous last words, I know...). Developer is usually Microdol-X and film is usually TMax 100. -- Nicholas O. Lindan, Cleveland, Ohio Darkroom Automation: F-Stop Timers, Enlarging Meters http://www.darkroomautomation.com/index.htm n o lindan at ix dot netcom dot com |
#12
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Dumb question processing 4x5
On 10/21/2007 2:42 PM Richard Knoppow spake thus:
"darkroommike" wrote in message ... Depends on the volume but for trials (at least) get a 8x10 paper drum, one that has dividers to separate 4x5 sheets, load it in your changing bag (note you may need to invest in a larger bag) and process on the tabletop in room light. i use a Unidrum and Uniroller for roll film and use an Omega Drum (Simmard) on the same base for the little sheet film I do. [snip] I also use Unicolor and Besler print drums for sheet film. I have found that I can get "bromide streaks" on occasion if the drums are rotated using the Unicolor motor base unless they are taken off several times during development and agitated sideways. Evidently there is not enough turbulance in the flow of the developer to move the reaction products away from the development sites in the long direction of the drum. I've had this problem specifically with Rodinal. Its likely it may not happen with other developers but its worth beign aware of. For what it's worth, I also use the Unicolor drum with the same motor base, and I've *never* gotten development streaks, but I've never used Rodinal in the drum. Just D-76, Microdol-X and HC-110, all without any problems. |
#13
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Dumb question processing 4x5
Robert Chin wrote:
I'm sorry if this has been answered before. This is a legit question so please bear with me. My set up is not optimum. I do not have a dedicated darkroom (for now at least). I've done many many rolls of film over the years. I throw everyting into a changing bag, load up a reel and no problem. I'm getting ready to process 4x5 sheet film for the first time. It requires a bit more space to handle the sheet film than rolls. Since I do not have a dedicated darkroom, I can't fill the tanks with the necessary chemicals, leave them on a tabletop, and just lift the film holder from tank to tank in the dark. So my question(s) is/are simple: I've heard that because the processing tanks for 4x5 film take so long to fill, uneven development could result. Is this a real problem, or is it the opinion of someone really obsessive? Would I be better off making a light tight space to do this? Advice welcome from all. Thanks. You can use Polaroid 55 for positive and negatives. Prints very nice, too. And you get that decorative edge without having to use Photoshop. There are dedicated film tanks for 4x5 and they must work or they'd be long gone from the market. Load the tank in the dark, keep your chemistry ready and process as you would 35mm in tank. Cheers |
#14
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Dumb question processing 4x5
"Ken Hart" wrote in message ... "Richard Knoppow" wrote in message ... snip I also use Unicolor and Besler print drums for sheet film. I have found that I can get "bromide streaks" on occasion if the drums are rotated using the Unicolor motor base unless they are taken off several times during development and agitated sideways. Evidently there is not enough turbulance in the flow of the developer to move the reaction products away from the development sites in the long direction of the drum. I've had this problem specifically with Rodinal. Its likely it may not happen with other developers but its worth beign aware of. The streaks show up as lines of lighter density on either side of dense highlights on the negative in the direction of rotation. What if the base were tilted just a couple of degrees? Of course this could make the streaks slightly diagonal, but as the developer 'runs into' the end of the tank perhaps it would agitate it sufficiently to prevent the streaks. I'd try it myself, but I've never experienced the problem. Maybe because I can't seem to level the motor base! (I use either HC-110 or C-41) I don't think this would work. The problem seem to be that there is not enough sideways agitation to dissipate the developer reaction products so they are dragged back and forth across the point where they are being produced. For medium densities there doesn't seem to be much effect but where one has a quite high density the effect is quite noticable. I noticed this first on a cityscape where there were direct reflections of a low sun in some windows. Those windows have streak which show up on both print and negative. Some developer reaction products, bromide and iodide for instance, inhibit development, some accelerate it. I am pretty sure that the negatives I first noticed the effect on were developed with Rodinal. The active ingredient in Rodinal is para aminophenol, related to Metol, which is sensitive to bromide and produces restraining reaction products. In normal use for developing color prints the effect is probably not noticable because prints are developed to the maximum density possible rather than partial development as is the case for film. This probably masks any small uneveness in development. In any case agitating sideways several times during development seems to cure the problem. -- --- Richard Knoppow Los Angeles, CA, USA |
#15
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Dumb question processing 4x5
"Robert Chin" wrote in message
... So my question(s) is/are simple: I've heard that because the processing tanks for 4x5 film take so long to fill, uneven development could result. Not if you use a film and developer you can pre-soak or use high dilutions with long development times. Is this a real problem, or is it the opinion of someone really obsessive? It's a problem for people who use film/developer/temps that yield short development times. Just don't go there. |
#16
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Dumb question processing 4x5
In article , pico pico.pico.net wrote:
"Robert Chin" wrote in message ... So my question(s) is/are simple: I've heard that because the processing tanks for 4x5 film take so long to fill, uneven development could result. Not if you use a film and developer you can pre-soak or use high dilutions with long development times. It's not really an issue with Jobo drums because the drum is _supposed to_ be already rotating, and the processor level (and the water bath properly filled so the drum doesn't float at an angle) before you pour anything into it. The pre-wet once recommended by Jobo can cause serious problems with some processes, for example C41. I have also seen it lower film speed when I was doing film and developer tests. I wouldn't use it. -- Thor Lancelot Simon "The inconsistency is startling, though admittedly, if consistency is to be abandoned or transcended, there is no problem." - Noam Chomsky |
#17
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Dumb question processing 4x5
"pico" pico.pico.net wrote in message ... "Robert Chin" wrote in message ... So my question(s) is/are simple: I've heard that because the processing tanks for 4x5 film take so long to fill, uneven development could result. Not if you use a film and developer you can pre-soak or use high dilutions with long development times. Is this a real problem, or is it the opinion of someone really obsessive? It's a problem for people who use film/developer/temps that yield short development times. Just don't go there. Depends on the tank. Let's assume that it takes thirty seconds to fill the tank. Let's assume you are doing C41, where the developer time is 3:15. The tank filling time is about 1/6 of the total developement time. That's a bad thing. Now let's assume that a different developer/temperatuire combination time is 15:00 That thirty seconds to fill the tank is now only 1/30 of the developement time-- not a big deal. If you are using one of the tanks where the film stands up and the tank requires a quart/liter or so of developer, it's going to take some time to fill. But you can process perhaps a dozen sheets at once. Just fill the tank in advance, load the sheets in the holder, and shove the holder into the full tank- start timing. If you are using one of the tube/roller styles tanks that only require a few ounces of developer (they don't need to be full), the fill time is not an issue. When I develope 120 rolls four at a time in C-41, fill time is an issue. I have two tanks. I load all the rolls on the 'spindle' (long center post that holds the reels). The tank is already filled with the proper amount of developer. I put all the films in the tank, start the timer, close the lid, and turn on the lights. The second tank has the bleach in it. When the timer reaches 3:00, I turn off the lights and get ready to pull the reels out of the developer tank and put them in the bleach tank. Essentially, this procedure makes the 'fill time' for a large tank only a matter of seconds. |
#18
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Thanks to everyone...Follow up Question...
Hi All:
Thanks to everyone who replied. This was a big help. I'm going to filter through some of the suggestions and figure out a better set up than what I have now. For now though I like the idea of a dilution that will allow me long development times. I'm using the Kodak Tmax film now. Mostly the 100, but in the future, I will be using the others. What is a good developer/dilution (preferably using Kodak or Ilford chemistry) that will get me longer development times, like in the range of 10+ minutes? The other problem (sort of) is that I like to work at room temperature because I just don't have a lot of room now. Room temperature for me is 74F. If it's possible, some description of how it will affect grain and contrast is much appreciated. Thanks again! |
#19
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Thanks to everyone...Follow up Question...
"Robert Chin" wrote in message ... Hi All: Thanks to everyone who replied. This was a big help. I'm going to filter through some of the suggestions and figure out a better set up than what I have now. For now though I like the idea of a dilution that will allow me long development times. I'm using the Kodak Tmax film now. Mostly the 100, but in the future, I will be using the others. What is a good developer/dilution (preferably using Kodak or Ilford chemistry) that will get me longer development times, like in the range of 10+ minutes? The other problem (sort of) is that I like to work at room temperature because I just don't have a lot of room now. Room temperature for me is 74F. If it's possible, some description of how it will affect grain and contrast is much appreciated. With Tmax 100, I've always liked Rodinal 1:50 @ 68 degrees for 11 minutes. Agitate continuously first 30 secs, then for 5 secs every 30 secs thereafter. And Rodinal is still available. http://www.freestylephoto.biz/sc_pro...t_id=&pid=4697 http://www.freestylephoto.biz/sc_pro...t_id=&pid=4698 If ambient temperature is a concern, use a water bath of 68 degrees in which you sit your loaded tank between agitation cycles. |
#20
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Thanks to everyone...Follow up Question...
"Lawrence Akutagawa" wrote in message
... If ambient temperature is a concern, use a water bath of 68 degrees in which you sit your loaded tank between agitation cycles. A water bath doesn't work for me because of the lack of workspace. Plus, I'm using those big HP plastic tanks for 4x5 film. Do you have any other formulas that would work? Thanks! |
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