Tank Capacity

marsbars · Jun 3, 2007

I am getting a list together of equipment to start processing my own film. I was going to start with a single reel tank until I get the hang of it and am getting consistent results. I figure at least if I screw up I only ruin one roll at a time. However everywhere I go I don't see a capacity listed on the tanks I am looking at online. I am talking about fluid capacity. I want to know how much developer solution will be used for each roll. For example if I am using Ilford DDX @ 1:4 and the tank that I buy holds 250-ml would I mix up only enough developer and water to make 250-ml. I am a newbie to development and haven't figured all of this out yet. I am mostly trying to justify the cost. I know that I lose some in the initial set up but I am looking at cost per roll just for chem. If it is close to what my lab charges then I will go for it but if it get s up there then it isn't worth it. I searched for tank capacity in the forums but didn't find what I was looking for. So if anyone has a rough idea of how much a single reel tank holds.

Kevin Caulfield · Jun 3, 2007

It depends on what kind of tank you are using. If it's a Paterson plastic tank, then the capacity will be moulded onto the bottom. From memory it's 290 ml for each 35mm roll. Some people will fill the whole tank to about 600ml even if processing just one film. You need to be aware that the tank can "ride" up the centre spiral during development, so either fill the whole tank, or use just a bit more than recommended volume, say 300ml, and use one of those clips above the reel, or an extra reel above the lower reel.

Edwardv · Jun 3, 2007

If the tanks states it holds 250ml of solution; then that is what you make to process the film. Paterson offers different tank sizes that can handle one, two, three, five and 8 for 35mm film, requiring 290ml per roll. When using 120/200 film some tanks can handle one, two, three and five rolls requiring 500ml per roll. At any rate, all the information is on the bottom of the tanks like Kevin Caulfied stated. If you are gonna use a larger tank to process and you are minus a roll or two, alway place more reels at the top so the reel with film will not slide when agitating. Best to fill the tanks completely full. Chemistry is cheap.

Kevin Caulfield · Jun 3, 2007

Oops, I meant the reel, not the tank, can "ride" up the centre spindle, not spiral.

srs5694 · Jun 3, 2007

The stainless steel tanks I've got both take 250ml for a single 35mm roll of film. Additional rolls add a bit less than the initial one, for both stainless steel and plastic; about 475ml is plenty for two rolls in my stainless steel tank, for instance. My stainless steel tanks, unlike the plastic tanks I've got, do not have capacities printed or stamped on them. Of course, it's a simple enough matter to measure it yourself.

IMHO, there's not much point to buying a single-roll tank for the reasons stated in the first post; you can always process a single roll in a two-roll tank. (That's how I've done 95% or so of the rolls I've processed.) I generally put an empty reel on top of the one I'm doing in my stainless steel tank, but I've forgotten a few times with no obvious ill effects. Plastic reels can reportedly "ride" up their spindles under some circumstances, though, so it's more important to have that spare reel -- or some other means to prevent this from happening -- when using a plastic tank and reels. (Stainless steel tanks lack the center spindle, so this isn't an issue with them.)

marsbars · Jun 3, 2007

So if I buy a 2 reel tank an only have one roll to develop I don't have to use the amount of chemistry that one would use for two rolls? Like I said I am new to all of this. I know that Chemistry is fairly cheap but I don't like to waste things if I don't have to. I like to get all the mileage that i can out of my gas and everything else that is consumable.

Kevin Caulfield · Jun 3, 2007

Yeah, just make sure the reel cannot move up the centre spindle. The easiest way to do that is to place another reel on top in a two reel tank.

fschifano · Jun 4, 2007

Look, you only need enough chemistry to comfortably cover the film in the tank. If that's 290 ml. for 1 reel in a 2 reel tank, then that's all you need to use. If you are using a plastic tank watch out that the reel doesn't creep up on the cnter core. If you don't have a clip to hold the reel in place, simply wrapping a rubber band around the core above the reel is a more than acceptable substitute.

I won't go into the relative advantages/disadvantages of the plastic vs. stainless steel tanks. Promoting one over the other can start a religious war almost as intense, and ultimately as fruitless, as the "what's your favorite film and developer combination" war. I have and use both types. Both have strengths and weaknesses. I use whichever has advantages that outweight the disadvantages for the job at hand.

What I will do is caution you against starting out with single 35mm reel tanks. They are too small and too limiting. There are advantages to using larger tanks. For starters, you might want to use dilute developers. You need a minimum amount of stock solution to insure that the developer does not become completely exhausted before development is complete. With D-76, that number is about 150 ml for each 80 sq. in. (equivalent to 1 roll of 135-36 or 120) of film. So a 1+3 dilution adds up to 600 ml. of total volume. Clearly that's not going to work in a small 250 ml. tank.

Monophoto · Jun 4, 2007

One of the things you need to strive for in the darkroom is absolute consistency in processing film.

If you have a tank that holds two reels, you should always put both reels in even if you are only developing one roll of film. The reason for this is that if you only have one roll in the tank (and depending on the design of the tank), it is possible that the reel would slip from one end of the tank to the other when you agitate it by inversion. That would result in more vigorous agitation than would be the case if you had two reels in the tank. And more vigorous agitation translates into greater contrast. Therefore, for consistency, always fill the tank with the rated number of reels.

It is also probably a good idea to use the full liquid capacity of the tank regardless of the number of rolls being developed. And for the same reason - if are developing one roll in a two roll tank, with only enough liquid for that one roll, it will slosh around as you agitate resulting in more contrast.

Edwardv · Jun 4, 2007

You may consider buying extra reels like 5, 6 or more and one larger tank that will allow you process more film to back up your standard tank.

eddie gunks · Jun 5, 2007

i mix up just enough cev. to develop the films i need. i use hc110 at high dilutions. i have had very good results with 1:119 and 1:63. i use ilford, kodak and foma films all with nice results. this will help you save on chemicals. it also make the dev. times longer. i agitate for the first 30 sec and then 15 sec every 3rd min. i like hc110 cause the syrup lasts for a long time and can be mixed as needed. D76 is also good, but you need to mix a stock solution. (be sure you have enough developer for the film. there is a min. required. google hc110. also google "the massive development chart. both are life savers)

now to answer your question......sorry. i fill my tank, pour it into a measuring device and you are away.

eddie

k_jupiter · Jun 6, 2007

Well, first off.. measure. Water in a tank with one or two reels. Pour it in, pour it out into a graduated cylinder or measuring cup. You will answer your question right there.

Second. Chemicals are cheap. Always fill the tank. Why? Because a partial filled tank induces swirling eddies and affects the processing of the film. Only developing one film with a full tank of chemicals also affects the processing, but to a much smaller degree.

Consistency is the hallmark to even, repeatable development.

tim in san jose

srs5694 · Jun 6, 2007

k_jupiter said:
Second. Chemicals are cheap. Always fill the tank. Why? Because a partial filled tank induces swirling eddies and affects the processing of the film. Only developing one film with a full tank of chemicals also affects the processing, but to a much smaller degree.

When processing fewer rolls than the tank's capacity, I never fill the tank to capacity. I've never noticed differences compared to rolls processed in full tanks (two rolls in a two-roll tank). Perhaps the effects you mention are just too subtle for my eyes. In any event, I'll take that small cost savings and the small environmental benefits of using less chemistry over some development effect that I can't see.

k_jupiter · Jun 7, 2007

srs5694 said:
When processing fewer rolls than the tank's capacity, I never fill the tank to capacity. I've never noticed differences compared to rolls processed in full tanks (two rolls in a two-roll tank). Perhaps the effects you mention are just too subtle for my eyes. In any event, I'll take that small cost savings and the small environmental benefits of using less chemistry over some development effect that I can't see.

If you can't see it, it don't exist. But if you want constancy, break rules only after you understand them. Obviously not an issue in your case. What I would be looking for is streaks across the film from over development because of developer movement.

tim in san jose

srs5694 · Jun 7, 2007

k_jupiter said:
If you can't see it, it don't exist. But if you want constancy, break rules only after you understand them. Obviously not an issue in your case. What I would be looking for is streaks across the film from over development because of developer movement.

Certainly I've seen none of that, except in the case of one roll, which had a crease in it that disrupted the fluid flow, resulting in regular vertical bars in about 1/3 of the roll. It was very odd. I'm not sure what created the crease, but I only saw it that once.

Shifting this back a bit to the original poster's situation, most people do make mistakes when learning to process film, and some fairly subtle things can cause problems. If you see problems like the streaks that k_jupiter describes, changing to using a full tank of developer could be one solution; but my own experience (and that of others who do as I do) suggests that there are other solutions -- perhaps a change in your agitation pattern, for instance, could correct the problem. All of this is just part of learning to develop film.

Mahler_one · Jun 7, 2007

Suggestion: Put both film reels in the tank. With the tank level, pour water in so that the water level in the tank is comfortably above the top of the bottom reel in the stack ( when you are developing, the bottom reel has your film which is about to be developed ). Now, pour the water out into a measuring cyclinder, and record the volume. The volume measured is what you need to cover the one roll of film loaded on the bottom of the two reels! Thus, if you find that the volume you need to completely cover the bottom reel when both reels are in the tank is, for example, 300 cc then make up your developing solution so that the total is 300cc. So, if you are using DDX at 1 plus 4, simply take 60cc of undiluted DDX and add 240 cc of water. Problem solved, and the very best of luck. Check to be certain that no minimum volume is needed in your particular tank-usually the details will indeed be on the bottom of the tank. Let us know how you make out.

Edwin

Mahler_one · Jun 7, 2007

I neglected to add that I believe that for each roll of 35mm or 120 film, or each sheet of 4x5 film, one needs two ounces of whatever dilution your developer is made up to. Obviously in most cases your volume will be well above the requisite two ounces. One of the times the "two ounce" dictum comes into play is when you might be developing multiple sheets of sheet film in one of the expert Jobo drums, or multiple reels with several rolls of film loaded on each reel in the Jobo or another system.

Edwin

Mahler_one · Jun 7, 2007

Might I amplify what I mean by two ounces of the correct dilution of developer? I arrived at the correct dilution and correct developing time by meticulous testing of my film and the construction of density curves. If one does not do such testing then I suppose that one should use, as a starting point, the suggestions of the manufacturer of the developer as to the dilution and time of development at a given temperature.

m

Tank Capacity

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