Hello everybody,
I've tried last week my Sinar F2 for the first time, with four sheets. And I've finished with four failures!
3 of the failures come from exposure errors due to, probably:
  • failure in "reprocity failure" compensation. My sheets are Arista EDU 100 and I've used a table found for fomapan 100. Meter gave 2s and I exposed 5s. Sure not enough.
  • forgotten the bellow extension. Hard to be a beginner and to think to everything. Reaching Large Format Heaven is a hard path ...

These 3 failures provide almost dark negatives, without details.

For development I've used (unfortunately) Taco method. I was sure it was an easy method for developing sheets in tanks. But after failing and reading LF forum, it seems this is not an easy method for beginners.
  • First, I've forgotten to check if tacos were well disposed in tanks. Unfortunately 2 tacos were nested.
  • Next, following what I've read in forum, it is suitable to use a bigger tank because sheets can move during process, and it is advised to block them. I've used the tank for 2 120mm reels. Probably the 3 120mm reels should be better.

My interogatons are about this 4th sheet. I've used a flash oriented toward ceiling. The right part of sheet is (relatively) well exposed and developed. But in the middle there is a white mark on the sheet. And below and around this mark, negative is pure transparent, we can see my finger place behind the negative.
Click image for larger version.  Name: IMG_20200102_153519.jpg  Views: 62  Size: 19.3 KB  ID: 198977
Click image for larger version.  Name: IMG_20200102_153631.jpg  Views: 64  Size: 20.0 KB  ID: 198976

So, my questions are:
  • What is this white mark? Is it related to the other nested sheet during process? Does it come from elastic used for taco?
  • What is the reason of the lack of exposition in the middle of the sheet, leading to transparent place? I can understand the black parts of the negative, due probably to lack of development during process (nested tacos). But not the transparency part.


I've decided to try, next time, developing sheets one by one in tray, preventing accumulating errors (installation in holder, exposure, development)

I hope I was clear in my explanations.
Thanks for your help.