Green spots with "taco method"

carbo73

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Hi,

I've used the "taco method" for LF development a couple of times, and my main problem was that I shaked the Paterson tank so much that most of the bands ended in the bottom and the sheets mixed. This was not quite good as uneven development appeared.


Last time I tried a much more gentle shaking BUT I reused the bands. And ended with negatives like this one (taken with a newly arrived 4x5 Crown Graphic), with a weird circle (only this negative in 5) and green spots.



Anybody has seen this with the "taco method"? I would not reuse bands again, but maybe even better use plain rubber bands, not the ones covered in textile (hair bands).


med_U73997I1539206315.SEQ.0.jpg
 
The green area is unremoved anti-halation backing, that dye may come off with additional washing. Or, you could pre-wash prior to development.

The circle... guessing that it might be from chemical residue contamination, possibly fixer, on your bands.
 
Well. Yours came out better than my attempt at the "taco method". Never again :mad:

The Mod54 or something like that is probably what I'll have to get. Tray method in mean time. Of course, I haven't been shooting LF for a while now, and probably won't until early next year. :(
 
The green marks appear to be residual anti-halation backing, as Larry mentioned. Usually occurs when the back of the film is touching something during processing. I tube-process 5x7 film and see these marks occasionally, but a 1 or 2 minute dip in a tray of Hypo clear takes care of it.

I've used BTZS tubes to process 4x5 for years, and my own homemade tubes for 5x7 film, and never once had an issue with uneven development.
 
Thanks to all. I will try the pre soak (water appears bluegreen when you pour it, right?), and probably change to a proper adaptor for 4x5 in the Paterson. But these only work with the larger ones, for a couple 120 rolls, right?
 
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