Tetenal C-41 bad blix and good luck
Hi all, happy 2020.
Last year I bought my first Tetenal C-41 2.5L pack and with careful use it lasted way beyond my expectations and gave me great results. About halfway through the pack I heard about Tetenal's financial woes and bought in a second pack for safety.
Wind forward to the end of the first pack and the first mix from the second pack, all conditions identical. The first film (Lomo 400, 120) was terrible but I was shooting with a potentially leaky folder and put it down to the camera. The next two films, however were with good equipment and they were also bad. What I was seeing were white (in reversal) spots and streaks on the scans. I looked at the negs and they were covered in small black dots. I rewashed the negs and with some "scrubbing" these could be reduced but not eliminated. I figured it was something in the mix so I threw all chemicals away, washed the bottles and made a new mix which I then run some test films through, including unexposed areas. The results were identical, tiny black dots all over the negs.
This is where my luck comes in, some time after buying the second C-41 pack but before starting it, I saw advertised some Tetenal blix from the 2.5L pack (that is to say nominally identical to that which I had in my C-41 kit) and I bought it with the intention of replacing blix more frequently to keep overall times down. I thus ran some more test negs using the same developer and stab but with blix from this separate source; this time the negs were perfect so logically the problem was with the blix in the second pack.
So in short:
Tetenal C-41 2.5L Pack 1 - perfect for 50+ films (so normaly no problems with my technique)
Tetenal C-41 2.5L Pack 2 Mix 1 - black spots from film 1 onwards
Tetenal C-41 2.5L Pack 2 Mix 2 - black spots from film 1 onwards
Tetenal C-41 2.5L Pack 2 Mix 2, alternative sourced Tetenal blix - perfect
All mixes were with deionised water from the same source, bottles were washed between mixes, all temperatures and processes were identical. All tests were made on multiple film stocks (Lomo and Kodak). All mixes were fresh and stored using protectan gas.
I can thus only assume that the blix supplied in pack 2 was somehow bad, and reproducibly so, from the moment of opening.
Has anyone else seen this problem or have any idea where it stems from?