Getting 'box' speed with Foma 100 and Forte 400

I'm taking a great risk next month: I'm taking my Plaubel 5x7 on it's first trip AND trying two new films at the same time. Because of price/availability in 5x7 and the lack of 5x7 holders, I am ordering these films to be sent to my brother in Illinois and will pick them up there along with holders. I haven't used either film before...I am only trying them because of recommendations I've read here and on other forums. I develop FP4, TX400, and APX100 in Xtol with good result, though I've never gotten FP4 to look exactly the way I want. I am hoping to reduce the variables involved in this experiment by sticking with Xtol.
My question is can I expect to get the rated speeds of 100 and 400 respectively from Foma 100 and Forte 400? I won't really have the opportunity to test since I'll process the film after I return from The States. I wouldn't do it this way if I had a good alternative, so I am asking for help.
I sure appreciate any and all recommendations!
Phil

I get about box speed from both. I have shot more of the 100 than the 400 and I get really good results with it at 100 with D-76 1:1.

I haven't tried it in other developers yet, but I ordered some more so that I could run some experiments.

Best I can suggest is to dilute 1+1 and extend processing as needed to get normal contrast -- perhaps, after you return, shoot a few test sheets in similar lighting to verify your process before committing your travel film. FWIW, I've been pretty happy with these films in HC-110 and Parodinal, using high dilution, reduced agitation, and extended processing (which combination tends to push up the shadows, effectively increasing film speed). I'd expect XTOL at 1+1, or even 1+3, to give excellent results once you arrive at the right time...

As you're probably aware, you're better off using a film with which you're familiar in a situation like you describe. That said, the general reputation of these films is that they should be shot at less than box speed. I've only done one remotely controlled test of the matter with Fomapan 400 in PC-Glycol and found that either ISO 320 or ISO 400 was the proper speed for me, using 35mm film and a diffusion enlarger. (My camera's meter gave me the same shutter speed and aperture for those two speeds, so I couldn't tell them apart in practice.) It's possible that PC-Glycol is better at pulling full speed from this film than most developers, though. Fortunately for you, XTOL also has a speed-increasing reputation, so you might be able to get full speed, or close to it, with XTOL, at least with the Fomapan 100. I have less experience with Forte, so I can't say much about it.

I don't use X-tol so take this with a pinch of (un-iodized) salt but, I rate Classic Pan 400 (which I think is the same as Fortepan 400) at EI-250 or EI-200. Even in Acufine, I only rate it at EI-400, or EI-500. I guess, I'd start by giving the Forte 400 about an extra stop of exposure.

Thanks for the advice gentlemen! I guess I'll just shoots mah films and takes mah chances. I'll rate the films at box speed then when I return home, shoot some more and process the unimportant stuff to find the right times. Or I'll bracket. Wait...forget I said that...no one brackets 5x7! Right?

Thanks again! Phil

Phil Woodney said:

Thanks for the advice gentlemen! I guess I'll just shoots mah films and takes mah chances. I'll rate the films at box speed then when I return home, shoot some more and process the unimportant stuff to find the right times. Or I'll bracket. Wait...forget I said that...no one brackets 5x7! Right?

Thanks again! Phil

Click to expand...

Hi Phil,
While I don't bracket my 8x10, I do tend to shoot both sides of a holder on the same composition. Then If I don't like the first neg, I can change my development of the second.

We can only speak for the Fomapan 100:

Xtol will bring you the iso 100 speed.

Best regards,

Robert

100 speed for Efke 100 seems just about right for me with pyrocat HD