View Full Version : Identifying a Darkroom Error?

24-May-2018, 17:29
I am shooting through my first box of film as I evaluate equipment and learn to develop at home. The first 2 shots (day interiors) were developed by a friend in a Patterson tank - no problems. The next six (day exteriors) I did by myself, also in a Patterson tank; Initial loading into holders and then into tank was done in a converted bathroom. Scans of all the negatives I developed have a blue cast which worsens in the center, but it doesn't appear to have a drastic effect on the negative's density as in shots I have with leaky film holders. Am I seeing the results of a light leak from when I was loading into my tank, some sort of mistake in the dev process (timing, temperature), a bellows leak that wasn't evident inside, or something else? I developed two at a time, folded inward along the long side and secured with rubber bands. I have two exposures left in the box that I can use for testing.



HT Finley
24-May-2018, 17:48
Invalid attachment, it says.

24-May-2018, 18:07
Invalid attachment, it says.
Fixed with embed.

Gary Beasley
24-May-2018, 18:30
What film and process, brand of kits?

24-May-2018, 18:54
What film and process, brand of kits?

Portra 400 developed with Jobo C-41 press kit, dish soap used in lieu of stabilizer at advice of person who did first development. Instructions advise 3:30 development and 6:30 blix @ 102 degrees Fahrenheit.

Jim Andrada
24-May-2018, 19:58
I thought C41 was always supposed to be developed at 100 degrees F. If temp is off I'd expect color shifts.

Gary Beasley
24-May-2018, 20:30
Are these scans of the negative or wet prints? And why would anyone replace the stabilizer with dish soap if you have it available? Its there as a preservative, not just a wetting agent like the dish soap is.
You would want to check the accuracy of the thermometer against a known standard if you can, still C-41 can stand some inaccuracy.

24-May-2018, 21:45
Blix your negatives again. If it's a fresh kit I am surprised it would have Blix issues, unless you mixed it wrong, or perhaps your temps drifted/dropped once you got to the Blixing. Regardless, put it back in (it won't hurt anything, unless you leave it in for days). Report back if that fixes it, but I am almost 100% sure that's your issue. It's come up many times wrt home developing. Generally, Blix longer than suggested and add time every time you use the kit as it oxidizes.

Mark Sampson
24-May-2018, 21:47
Hmm. I recall that the correct development time for C-41 was 3'15" @ 100.5F. That was in several different processing machines. But your process regimen is a bit different. I see no light leaks... your troubles might be from development, or perhaps improper or inadequate bleach/fix stages. Using dish soap can't be good although I ]have no ideas what problems that might cause. Within Kodak (where I ran a C-41 line) we went by the book, which of course was written by our colleagues. Try shooting an X-rite color checker (or similar) under known conditions, like sunlight. That may help determine what's going on, and may help to suggest a fix.

Jim Andrada
24-May-2018, 22:13
Otherwise known as 38 C no doubt! That's where I always set the Jobo and what I checked with the Kodak process thermometer I set next to the drum. Do you remember the official tolerance for C-41?

Anyhow, I think the time/temperature could be causing a color shift.

By the way - found something that gave 37.8 C +/- .5 C for 3:15

25-May-2018, 01:22
37.8 and 3:15 thatīs what the paper sayīs in the tetenal kit....

well, agitation??? temperature maitenance???

jobo probably is giving you times for continuous agitation... in a rotary processor...

the atl 1000 that i use came with an already programed time and temp for c41 and it was 3:15 @ 37.8...

i would separate the bleach and the fixer... they last longer that way (iīve been using the same ten liters of bleach for 3 years now, just correcting ph and agitating each development) but then... in a kit itīs the same...

25-May-2018, 12:39
Looking at the instructions for the Jobo kit and it advises 39C for 3:30 using hand tank, agitating 4 cycles every 30 seconds after the first 10 - Their rotary instructions however are 3:15 @ 38C. Hand tank is also supposed to be done in tempered water bath which I failed to do, so I'm guessing my blix cooled too quickly, I am going to try and reblix tonight. Their own troubleshooting also suggests that magenta negatives are a sign of overagitation or developer being to warm, next batch will be done at lower time & temp in a tempered bath but it's interesting that they suggest developing hotter and longer, maybe to account for cooling?