Fomapan 100 4x5

I just developed some fomapan 100 4x5 b&w testshots. Some came out as exected and one did seem to be very thin. At first I thought I must have made a mistake when taking the shot, though I could not think of any.
Anyway I was just about to throw the negative away and redo my series of testshots when I took a closer look.
The faint image visable on the developed negative is a positive. Somehow a reversal must have found its way into the negatives, or how else can a negative develop into a positive? This is really strange. The negative/positive has the same notch as the other negatives.
I hope this does not happen too often, that would be a real pain.
I am quite new to lf format and thought I use a more economical film to practice with but it would be no good if 'some' of the film turns out to be positives and ruin a potentially nice shot.
Has anyone had similar problems?
Christian

it sounds lik eyou're blaming the film?

Most likely this is an error in your processing or exposure.

Please provide more details...

What chemistry did you use to develop the film?
What was your development method?

What was the measured light?
What was your exposure?

How far away were you focused?
The more details you provide, the better chance people will have in helping you figure out what you did wrong.

It could be you haven't fixed all the silver out of the emulsion. This could then look like a 'positive' in reflected light, at a certain angle etc.

Try fixing one of those sheets again, for more than double the clearing time, and see what it looks like then.

Any chance that you loaded the film into the sheet film holder backwards?

Thin negatives show a positive when held in the correct orientation to the light. If your image has shadow detail, then you probably under developed. If all you have are highlights, then it is probably under-exposure also.

Many thanks for the tips what could have gone wrong.

Here is what I did: I took a series of 4 shots of the same scene for a personal EI for fomapan 100 4x5.
I took my meter reading from the shadow area I want to render as Zone III.
I took my shots carefully, checking all settings etc, changing from ISO 100 to ISO 50 with each shot.
So far so good.
I marked all the negatives before developing by cutting of a corner of each negative according to which number of shot it was, i.e. one corner for the first shot, two corners for the second shot etc, so that I could easily identify them later. I then put the negatives insight of an old 4x5 negative box and the box inside an old black back to protect them from the light, while I set up my chemicals etc.
To develop my negatives I use home-made PVC tubes (1.5 inches in diameter), black ones used for plumbing which I bought in a DIY shop and cut to 5 inch in length.
The tubes are open and the negatives are inserted into the tubes in total darkness and then the tubes go into and old Durst Codrum paper daylight development drum, which takes 3 tubes at a time.
This is the first time I did develop this way. I used the tray method before, but I wanted to try a method to develop in daylight.
The first 3 negatives that I developed (R09 at 1:50 for 7 Minutes) where shot no 1, no 3 and no 4. There is no reason to it, just the way I took them out of the film box.
These negatives developed okay, as I said already, they developed as expected.
When I insert the negatives into the tubes I feel for the notch, make sure it is in the upper right corner and then curl the negatives to fit into the tube, emulsion side up.
The next negatives I developed were shot no 2 and a blank negative.
Here no 2 shot was almost clear with just the faint 'positive' looking image and the blank negative was clear (as expected).
I wonder now as chazzy said, whether I had a lapse of concentration and inserted this negative the wrong way into the tube.

Anyway I learned something new, many thanks for all your answers.

I've used the stuff 4x5" as Arista EDU Ultra, never really liked it, mine came out kinda thin as well, I'd recommend increased development.

If you want cheap film in 4x5 I'd recommend picking up Shanghai 4x5 or ERA 4x5.

Acoording to your dilution of rodinal, 7mns (1+50) is okay for Foma rated at 50iso but way too short if it is rated at 100 iso, in that case, try 10mns..
Foma 100 is not as easy to process as , say, FP4+, but if you learn how to process this film , you will not be disappointed , considering that it is also the most affordable.
Recently i discoverede how foma 100 and Pyrocat Hd . It is a superb combo...
Keep that in mind for later experiments.
Cheers.
Angelo

Now that you know you had a problem with one specific negative, and have reason to question whether or not you made a mistake, the next step is to see whether or not you can reproduce the mistake (the thin negative.) You should re-shoot the shot and then re-process it, making sure you insert film correctly into holder, cannister, etc. If the negative comes out correctly then you assume you made a mistake the first time and write it off. If the negative comes out thin again then you can begin analyzing exposure and processing to try to isolate the cause. But my guess is that the second time around, the negative will be fine.

Mike

Coming late to this thread but I though I would add my experience. I use Fomapan 100 rated at 50iso and developed in Pyrocat HD (1:5:94) for 11 minutes at 20 degrees C. This time was on the helpful recommendation of another APUG member. My dilution is because I use Sodium Carbonate in part B rather than Potassium Carbonate. I found that the negatives on first inspection seemed a little thin but when I printed them I got sufficient shadow detail at zone III and good open shadows at zone IV. Zone II shadows showed a hint of texture. I feel that had I rated it any higher the zone II shadows would have dropped off the scale and end up as a featureless black.

One thing I did notice was that it was a contrasty film and I can print these negatives at grade 2 in a diffuser enlarger. I anticipate that I would have needed grade 1 if using a condenser enlarger.

What disappointed me the most was that 5 out of six of the sheets I shot had defects which ruined the shot. I am investigating these but do not believe that they are processing errors. Ilford FP4 processed using the same methodology came out fine.