View Full Version : C-41 is a gas

Jim Andrada
7-Sep-2014, 23:44
Well, maybe more of an outgas!!!

I've been running Tetenal C-41 in my Jobo for years with nary a problem

Last night I ran a batch and noticed that the Blix bottle seemed a bit swollen but didn't think too much of it when I uncapped it. But when I dumped the Blix I got a whiff of something BAD! Almost felt like inhaling Ammonia. My sinuses burned for hours and I just dumped in a load of wash water and left the room. The exhaust fan had been on the whole time.

The only thing I did differently this time was to prepare the solution (from the powder kit) the day before instead of shortly before running the film. Also might have had the agitation set a bit faster than usual. I've heard of Blix outgassing issues including sometimes popping the lid of a daylight tank, but had never experienced a problem myself. I had no idea it would be so dramatic, but I felt sick for a few hours afterwards and even had some residual burning sensation in the sinuses this morning. Very unpleasant.

The negs look great, but I'm a bit gun shy about running the next batch. I think I'll take a few precautions next time just in case. A hundred years ago I was a chem/physics major and I've worked with some nasty stuff in the lab with proper precautions, but this was really unexpected and unpleasant.

David Lobato
8-Sep-2014, 01:36
Was it possible the bottle was contaminated? Another thought, could exposure to high temperature have caused the outgas?

Jim Andrada
8-Sep-2014, 10:25
I used a new bottle so I don't think that was it. I've heard that agitation or shaking can cause the Blix to outgas and have heard of it popping the lid off of a Jobo tank, but this was pretty extreme. I'll try slower rotation the next time, and wear a mask, but this was bad enough that there should have been a serious warning in the box. Something that outgasses like this should probably only be used under a laboratory hood or with direct vapor extraction. I felt sick for more than 24 hours.

Temperature may also be a possibility but it never got as hot as summer daytime temperatures in Tucson.

Negatives on the other hand were very happy.

8-Sep-2014, 10:38
its not C-41 in general. Its Blix. Look at the chemistry list. Think what mixture does when heating. Act accordingly. I mean its school chemistry in there, so you can certainly see what would react.

Jim Andrada
8-Sep-2014, 11:25
If it had been heated much above the operating temperature I could understand it - but at no time during the process was the temperature above 100.5. I keep a lab thermometer in the water bath itself as a check on the Jobo temperature control and check the individual chems before pouring them and everything was within tolerance. Jobo's instructions actually say to mix the chems slightly above operating temperature. The temperature did fluctuate a couple of degrees high before stabilizing and starting the process, but during the process everything was in tolerance - this is why I'm so surprised. There was no significant/noticeable outgassing from the open Blix bottle after I removed the cap and released the slight pressure buildup before starting the developer.

One thing though - there was still developer in the waste tank when I poured out the Blix. I hadn't thought of that as a possibility.

8-Sep-2014, 11:46
Wow, that's quite nasty! I don't have a "real" darkroom as I (currently) only do film dev using a Jobo so I don't even have a ventilator in the garage. Hopefully there's no lasting effect.

I mixed C41 at their recommended temp and E-6 at ~125 degrees (C). No problem yet.

Jim Andrada
8-Sep-2014, 15:25
I feel fine today so it appears not to have been life threatening. But it was quite a surprise. Hopefully I won't have any more such surprises.

I think the garage should be OK - I was set up in a guest bathroom which is pretty confined.

Terry Christian
9-Sep-2014, 06:53
Yes, blix does create gases. Be sure to burp the tank every so often. Freshly-mixed blix tends to outgas much more than raft which has been reused a time or two.

10-Sep-2014, 18:32
Fresh blix will outgas like a volcano science experiment. First few rolls of fresh blix, I leave my fill cap off of my SS tanks between agitations. Otherwise it will leak out from the gassing anyhow.