Combi Tankgreenspun.com : LUSENET : Large format photography : One Thread
So far I've mainly used transparency film in 4x5, but I bought a secondhand HP Combi Tank on ebay recently in an effort to improve my use of black and white film (and to avoid the high cost of getting b/w film developed). I have some basic questions ;
1. It is quite slow to fill the tank - I understand that it will probably be easier to fill the tank with developer first, and then, in the dark, put the film holder in, put the lid on, after which the lights can be turned on. That's fine ; however, it also takes about 30-45 seconds to drain the developer from the tank - how does this time affect the selected developing time? Do you have to factor the drainage time in as part of the development time?
2. After draining the developer, you have to get stop bath and then fixer into the tank. How is this done efficiently? Is it simply best to go back to the dark, remove the lid, pour the chemical in, and then replace the lid? To do this somehow seems to defeat the purpose of having a daylight tank (!) so is there a simpler way that I just haven't fathomed out yet? Pouring the chemical in through the top valve unit is so slow (because the displaced air has to escape) that I can't believe that this is the way to do it!
Sorry that these questions are so basic - I would really appreciate some experienced advice.
-- fw (email@example.com), November 28, 1999
The simplest way is to return the Combi Tank for store credit and get a Beseler Motor Base and several of the accompanying print drums. I have used these to process 4 X 5 to 8 X 10 sheet film with nary a complaint. The entire process can be carried out in room light after loading and you only use 75ml - 150ml/run of chemistry. Very simple and if purchased used inexpensive. I have not used the Combi Tank or the old Yankee - I was advised against both because of the volume of chemistry required, the possibility of bromide drag and uneven agitation, and the general "sloppiness" - spilled chemistry, pouring in and out and so on.
-- Sean yates (firstname.lastname@example.org), November 28, 1999.
P.s. Go tot he archived questions & responses under the topic "Darkroom Film processing" There are a number of posts there which might help.
-- Sean yates (email@example.com), November 28, 1999.
The Combi is the one daylight tank that actually sort of works. I would agree that you might enjoy the whole thing more if you gave up and tried the drums or pvc tubes spun in water bath, but you probably want to get started with what you have so give it a try. They do use a horrendous amount of chemistry but you can reuse D76 if you use care and keep track of what you're doing. As for the time it takes to pour: don't worry about it. Use a dilute enough solution that you have a 9 minute or so development time and 30 seconds either way won't make a whit of difference.
Another thing you might try is stand development, which your tank is ideal for. FX-2 is said to work beautifully but I haven't tried it much yet so I can't give any real answers.
-- Erik Ryberg (firstname.lastname@example.org), November 28, 1999.
I had a Combi-plan tank once and the guy I sold it to still uses it all the time. I found that like with stainless steel tanks, if you just start the timing cycle at the point at which you have just filled the tank, for example, and start emptying at a point in the cycle just shy of the time it takes to get all the liquid out, you can achieve some fairly consistent results. If you haven't discovered this already, you must process at least 4 sheets in that tank. If you are interested in another low capacity (36 oz.) tank processor for 4x5, you might search for an old Nikor stainless tank. These hold 12 sheets and are adjustable for all kinds of cut film 4x5 and smaller. One caviat with the Nikor is that you'll have to bath the negs in a tray of dilute Sodium Sulfite to get rid of some of the antifogging layer that fails to get contacted by the developer. This sounds much worse than it is. I've been using this system with excellent results.
-- Robert A. Zeichner (email@example.com), November 28, 1999.
As for the drain developer and stop opperation, I pull the plug on the bottom and let it run into the sink while I begin adding running water through the funnel on top; washing is occuring simultaniously with draining. And then I just wash it like that for a few min., then fix. The catch comes in agitation which I have never mastered. If you don't get the top of the film anchored in the notches firmly, a sheet of film can stick against a neiboring sheet of film and foul-up the development. This has been my main complaint with the process. Perhaps someone knows the technic which prevents this problem.
-- david clark (firstname.lastname@example.org), November 28, 1999.
I've been usinga Combi-Tank since I took up large format last year and there are a couple tricks to follow. 1) You need to use longish developing times so the slow drain and fill doesn't affect negative contrast. 2) Start your timer when you start filling the tank and begin draining as soon as the timer sounds. This made my negative quality predictable. 3) Refilling the tank requires a funnel (if you didn't get one) and opening the top airway by unscrewing the valve two or thre turns. 4) agitation, get rubber gloves and treat it like a thirty five mm tank. 5) The last thing that really help during development was making sure that the two valves were on opposite ends of the tank. 6) As for film crunching I've had the best success with not putting the top clip on too tight. It doesn't stress the film and warp it in the slot.
The Tank isn't an ideal solution but, if your like me and live in a small apartment its pretty much the only option. I do get solid dependable results but I'm anal about repeating the processing steps each time. If not I get very poor results.
Hope this helps
-- kevin (email@example.com), November 28, 1999.
I have been using the Combi-tank for a few months since taking up LF. So far I have not had any problems with timing of developer etc (with the slow fill-up and drain times). I have found that you can speed up the filling process by using the funnel provided and by turning the valve on the lid until the "arrow" is parallel to the short side of the lid.Does this make sense ? This seems to free the air-lock without allowing daylight into the tank and I am able to fill the tank in less than 30 seconds. The same applies with pouring used chemicals out, I open the plug on the valve and twist it until the "arrow" is parallel to the short side of the lid. The chemicals drain fairly quickly. My only complaints are : the quantity of developer required (especially when using one shot), the fact that sheets of film have regularly escaped from the holder and stuck to the walls of the tank. However, Having spoken to the supplier NOVA (in the U.K.) they suggest the follwing (which I will try this weekend !!) : 1 Do not use the small blue washers on the holder, discard these and the holder sides are free to move a mm or so to hold the film more secure. 2 Do not agitate the tank as you would do for a spiral reel. They suggest rather than a full twist as you would do with (say ) a Jobo or Paterson, try a much gentler tilting motion !! The quantity of chemical in the tank ensures that the film is always covered in developer/fixer etc and therefore "aggressive" agitation is not necessary. I will let you know how I get on !! As yet I have not had any problems with streaking of developer either from slow filling or agitation, even with Pyro developer. Paul
-- Paul Owen (firstname.lastname@example.org), November 29, 1999.
As some of you know we, HP Marketing Corp., are the manufacturers of the HP Combi Plan T tank.
Nova was correct.
If any of you are using the blue washers throw them out. They were for converting the carrier to take 12 sheets of 6x9 cm film. They are not needed for any other size, including 6.5 x 9cm.
Also the description of filling and emptying by opening the air path is correct and very important as is the use of the funnel. Otherwise we would have stopped including it years ago.
If anyone has specific questions on the use and agitation (inversion) with of the Combi Plan we would be happy to answer them. And no we will not bring back the roll tanks or the 57 tanks.
-- Bob Salomon (email@example.com), November 29, 1999.
I have been using mine for years, and I find it a very good system. I don't normally use the slotted loading guide; instead I have learned to feel when the films are correctly loaded in the slots. The guide works fine, I just don't use it. I don't mash down on the top clip, just bring it down until I can feel that the film edges are secure.
The top needs to be pressed down snugly all the way around, so it won't leak when the tank is inverted. The spigot in the lid is light tight if it isn't opened more than a turn or two. It needs to have the funnel placed in the center hole. It allows air to escape around the edge as the chemistry is poured in. The bottom spigot is light tight if it is not unscrewed. Use the little cap to drain the chemistry. Uncap the top opening while draining. It will empty in about 35 -- 45 seconds this way. Just include the times in the processing time as suggested.
I use HC-110 at 1:31 dilution, one shot. My normal times for Arista run around 9 -- 14 minutes depending on scene contrast. I am not concerned about a minute more or less -- I don't see any adverse results either way. This assumes contact printing or cold light enlarging.
I get consistently even development, particularly sky values. The Yankee style non-inverting tanks always leave an area of higher density in smooth areas like skies. I have quit trying to use them.
My agitation schedule with the Combi is about 30 seconds of GENTLE over-and-back cycles the first minute, and about 3 cycles each minute thereafter.
I had the glue separate on the two spigots, one of them while halfway through fixing. I re-glued them with Pliobond, which is MEK based. No problems since.
I can recommend this little tank. It is just right for developing one Grafmatic magazine (6 sheets) I have not tried to crowd more sheets in. I would be afraid that the backs would stick together and result in ruined negs. Stick with 6 at a time.
-- Tony Brent (firstname.lastname@example.org), November 29, 1999.
I find better to use two tank so you don't waste time when you chance bath. so you just have to close the light when you change bath. but if you don't want to have a continuous agitation try tube
-- nze christian (email@example.com), November 30, 1999.
I want to thank everyone who has responded to my original question. The replies are really helpful and constructive - this is a great forum!
-- fw (firstname.lastname@example.org), November 30, 1999.