Underdeveloped film - how much to push or pull?

[travelerb]

Just got back from a wonderful trip to Yellowstone, but had a couple little snafus while there that I need some help resolving. I've been trying to get more into film, after rediscovering photography with a dSLR. Here's the problem:

I love my F100 and F5, but I have this little habit of forgetting to check/set the ISO when I change film. For some reason (maybe because they are used), they don't always sense the DX encoding. I sometimes get excited and start shooting without double checking, as if it were a digital camera with instant "results."

This happened twice, and I realized the problem most of the way through the roll. Instead of trying to "fix" it and only get a few "correct" exposures when I had it developed at the listed ISO rating, I just decided to let it ride and see what happened if I had the whole roll developed at the ISO that I shot at. The problem is, I'm having a hard time figuring out what to tell the lab in terms of "push/pull this roll by ___ stops." I've tried, but most of the information I've read about pushing or pulling is written in terms of doing it on purpose, which I have not done. I'm just trying to see what happens.

So, could anyone be so kind as to help me with the instructions to the lab? Here's what I exposed:

1. One roll of Kodak BW400CN was exposed as if it were ISO 40.
2. One roll of Fuji Reala 100 was exposed as if it were ISO 40.

And if anyone can offer any other options or possibilities for developing these two rolls, you are welcome to it. I guess given this has happened before, only having 2 screw ups out of 20 or so rolls isn't awful. Film has certainly made me a little more careful, but apparently not quite careful enough.

 

[Actor]

Here's what I exposed:

1. One roll of Kodak BW400CN was exposed as if it were ISO 40.

Theoretically you should pull it three stops. However, this is a chromagenic film like Ilford XP-2. If it has the same range as the Ilford you might get away with not pulling it at all. Three stops is a lot to pull any film. My instinct is to pull it just one stop (maybe two stops).

2. One roll of Fuji Reala 100 was exposed as if it were ISO 40.

Pull 1 stop.

 

[christopher walrath]

I'm with Actor. The Fuji would probably be fine at one stop but it's gonna be dicey with the BW400CN. I would say two stops as well but I would absolutely not take this to a one hour/send out service. Take it to a shop that sells fixer on the floor and make sure the person that helps you completely understands what you want done and even ask to have the lab they send to if they might be willing to contact you to verify what you want done.

Oh, and I do it myself. Twenty years shoot with MD Minoltas and you'd think I would have it down by now. I do that once or twice a year and smack myself in the forehead upon realization.

 

[travelerb]

Here's what I exposed:

1. One roll of Kodak BW400CN was exposed as if it were ISO 40.

Theoretically you should pull it three stops. However, this is a chromagenic film like Ilford XP-2. If it has the same range as the Ilford you might get away with not pulling it at all. Three stops is a lot to pull any film. My instinct is to pull it just one stop (maybe two stops).

I messed up a little, and this reminded me. That's what I get for posting off of memory. It actually was a roll of Ilford XP-2, not the Kodak, that was exposed as if it were ISO 40.

That being the case, pull 2 stops? Just one?

And thanks for the advice Christopher. I'm actually sending this off to NCPS, who has always done well for me in the past, and really understands everything. When the order form has the option on it to push/pull, as well as to cross process, you've gotta assume they take care in what they are doing.

 

[Actor]

I messed up a little, and this reminded me. That's what I get for posting off of memory. It actually was a roll of Ilford XP-2, not the Kodak, that was exposed as if it were ISO 40.

That being the case, pull 2 stops? Just one?

Ilford's data on XP-2 says that it can be rated as low as ASA 50 without being pulled at all, albeit the negative will be dense. They also state that the rating of ASA 400 is based on "practical considerations" and not the ISO standard. Other sources indicate that the "true" rating of the film is between 250 and 320.

Given that I would not pull it more than one stop.

 

[travelerb]

Thanks actor! I'm finally getting around to sending it off today, with the last few rolls I shot.

The first batch I sent off are already heading back, so I'm keeping my fingers crossed that my first big trip with film has some good results.