120 roll failed to develop

I developed 10 rolls of 120 using a large Paterson tank that can hold 5 reels by loading 2 films sequentially with tape lightly placed to hold the 2 films together. I loaded until the 2nd film just cleared the loading tabs.

The developer was Rodinal 1+50 (50cc total) so 5cc/roll for 8 minutes. I agitated using the included spin agitator every minute for 10 seconds after the initial 30 seconds of continuous initially. (this is the first time I tried this instead of inverting the tank completely)

The bottom reel had both films develop fully while the rest, only the outside (last loaded) film developed. The inside films were mostly completely transparent.

I did another tank with Xtol 1:1 as well and a similar thing occurred.

I think this exemplifies that there is a need for more vigorous agitation or is loading 2 films on a single reel fraught with the risks of failure? Is there a more fool proof way to load 2 films on a single reel since I have many rolls to develop?

Did the inside films have any signs of a neg and was the film type etc developed on the film edges?

The use of the word mostly suggests that there was something on the film albeit very faint. Apart from the bottom two films where the tape kept them apart and were successfully developed could the others have separated from the tape and the outer film then covered the inner film?

It is all I can think of. Can't be lack of developer the way you describe the results nor faulty dev if some developed OK

Can't see agitation being the issue either. On a continuous reel the inner film has to receive as much dev flow as the outer.



pentaxuser

Do I understand you correctly to be saying that you used 2.55 litres of working solution developer (50 ml concentrate diluted into 2500 ml of water)?

How did you ensure that the working solution was evenly mixed?

It sounds like insufficient mixing.

I looked at the film rolls as they were pulled off the reels. Most of the film were completely clear, no sign of film brand/type etc. I used 2.5 l of developer which I mixed for minutes with a stirrer as it was sitting in a warm water bath to bring it up to 70 degrees F.

My methodology for loading the films is to load the first film completely past the tabs on the reel a cm or so, then start the 2nd film until it touched the initial film. I then attached a narrow piece of masking tape lengthwise lightly to attach the 2 films together. Either this was not enough to prevent the films to "slide" past one another so only the emulsion of one was exposed to the developer. I know others develop 2 120 rolls on a single reel so it is not impossible. I don't think I can line up both films lengthwise (off the reel) with tape in complete darkness end to end so that it will load on the reel easily since they have to be pretty well aligned and the ends are not always square.

Can anyone who does this regularly give me some tips on how to load the 2 films on the single reel?

My first thoughts are developer failure, too little developer activity for such a large quanity of film. 10 rolls of 120 film in one tank is a lot of silver to reduce. The bottom rolls developed because they received the fresh dev first which became exhausted very quickly as it moved up the tank. Couple that with less than aggressive agitation and you will have problems. Do the developed rolls have normal contrast ( dense highlights) or do they look kind of flat? To me, 8 minutes at 1:50 is not near long enough time for that much film. Are all the films the same type? shot under the same light? Do you have scans of the "good" negs that we can see?

randyB said:

My first thoughts are developer failure, too little developer activity for such a large quanity of film. 10 rolls of 120 film in one tank is a lot of silver to reduce. The bottom rolls developed because they received the fresh dev first which became exhausted very quickly as it moved up the tank. Couple that with less than aggressive agitation and you will have problems. Do the developed rolls have normal contrast ( dense highlights) or do they look kind of flat? To me, 8 minutes at 1:50 is not near long enough time for that much film. Are all the films the same type? shot under the same light? Do you have scans of the "good" negs that we can see?

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You may be right Randy. I think next time, I will use Rodinal 1+25 and agitate with inversions instead of spinning. If I use 1+25, would I use the appropriate time for the more concentrated developer or would my starting point be longer given the large surface area of film involved?

I think Randy hit the nail right square on the head here. Make sure you have enough developer per sq in of film as per instructions. Rodie's stats fail me at the moment. But, um, +1.

My take is that there was enough developer per film - after all, 5cc in 250cc is the normal 1:50 Rodinal usage for a single reel 80 sq in 35mm/36 load in a stainless tank.

I think the OP's suggestion that the films didn't load sequentially but that the second film slid behind (or in front) of the first is correct.

I take it these are "walk-in" ratcheting reels? A reasonable bit of force is needed to slide the whole of a film into the reel, and a light application of masking tape may not have been strong enough. A stronger tape may make the trick work - try using Scotch tape on both sides of the join. The tape Kodak uses to secure 35mm film to the spool would be ideal.

It might be a good idea to do a practice run with the lights on and using scrap film - it might show just what did happen when the reels were loaded.