Developing different films, together.

Hi,

I have returned to photography after a long break and have shot and developed my first half a dozen films. Everything seems to be going fine and I am looking forward to printing my negatives.

But....I mostly used to develop films in pairs. It is more conveinient that way.
Last night I developed an AGFA 100 and a TRI-X, both in Rodinal. These are both new films to me, I Just happened to aquire some TRI-X and agfa 100. Developing them together meant an extra minute over the recommended time for tri-x, but I fancied a gritty, high contrast effect as these were documentary type portraits, so that was fine.

When I emptied out the developer I was a big shocked by the amount of very deep purple dye that must have come out of one of the films. I assume it was the agfa? (despite prolonged fixing and washing it still has a slight bluish stain, the tri-x is quite clear)

So, the tri-x has been developed in rodinal & agfa film sensitizing dye and whatever else washes out of each emulsion. DUH! :rolleyes:

I did it without really thinking, previously the films I developed together were usually the same.

Curiously, both films look pretty good at first glance, so no major harm done - but has anyone any idea how much affect mixing films together like this would have? Does it make much difference?

My initial reaction is that it can't be a good idea, but I suppose in the days of busy commercial labs processing BW films, a lot of stock must have got dunked together in big tanks of developer.

Any thoughts?

Steve

I, too, have developed 400TX (also 320TXP) in the same tank with another film (in my case it was FP4+) using Rodinal (1+100, semi-stand for 1 hour at about 72F) and had the purple runoff. No harm done AFAIK. My thinking is that if that runoff doesn't harm the "source" film itself, then I can't think of a reason why it would harm the other film. But I'm not a chemist.

You can develop anything you want at the same time in Diafine!

Good Afternoon, Steve,

Do you use a pre-soak? I suspect not from your description. It sounds as the color you observed is simply the anti-halation layers from the film. It's highly unlikely that the dye from either roll had any deleterious effect on the other. If you had used a pre-soak, you would have noticed the color when you dumped the water prior to developing.

Generally, there's no particular reason not to process different kinds of film simultaneously--provided that the development times are reasonably similar. If different times are required, just be sure that the film requiring the shorter time is on the top reel; then open the tank (lights out, of course) at the appropriate time and drop that reel into the washer while you complete developing for the film requiring more time. Is this a hassle? Not really. I always pour developer in and out by removing the tank top and operating in the dark for a few moments anyway. It's a little easier to get fairly precise development times that way than by pouring through the light trap in the tank lid.

One thing to keep in mind--T-grain film requires a longer fixing time than the traditional stuff. If you process, say, Tri-X and T-Max, be sure to go with the longer time required by T-Max.

Konical

There is a recent discussion about the dye and washing, the consensus is that it's not a problem. With sufficient washing it should mostly, if not entirely, come out.

The dye in film is easily removed by the developer solution, and the remainder by fresh fixer or washing aid. If you like to have clean negative, washing aid is very useful for this purpose.

Although rare, there are cases where developing different kinds of films in a single solution can ruin at least one kind of film in the tank. Usually, the slower speed of the two comes out thinner than when they were developed separately for the same time. Most developers don't have this problem though. (One of my favorite developer does this when I develop Tri-X and T-MAX 100 together, for example.)