It's not the film base, more the relatively thin emulsion (if it's anything like APX 200s, 7.5 micron total), and probably the silver/m2 needed to deliver higher average gradients than film designed to deliver normal contrast at sea level.
thinness of Aviphot
YupIt's not the film base, more the relatively thin emulsion (if it's anything like APX 200s, 7.5 micron total), and probably the silver/m2 needed to deliver higher average gradients than film designed to deliver normal contrast at sea level.
Wait a moment, this is interesting and not OT to me.
Are you stating that the finest grain a film has (or a developer imparts to a film - it comes to mind Perceptol for example) the less sharp a film is?
On the contrary, Rodinal and Ilfosol 3 are the most sharp developers around?
That's only a part of the story.
The high frequency information transmission capacity of a given emulsion is effectively limited by the granularity (quite severely) and/ or where the MTF response falls off (as that enhances the visibility of the granularity).
Therefore if you design an emulsion that has extremely high low frequency MTF response, and a slightly faster roll off at high frequencies it'll look both much sharper and finer grained than one that has a less strong MTF response at lower frequencies and a longer roll-off at higher frequencies.
In the real world, despite what high contrast resolution tests might suggest, there are very real limitations as to how much useful resolution a given opto-mechanical system can record on film, but getting the highest possible MTF below 40 cyc/mm will look dramatically better perceptually than any of the claims over whether an extra 10 lp/mm at high frequencies makes a difference.
And that is what really matters in making convincing big enlargements - not whether a film can resolve a high contrast target at 110 or 120 lp/mm (the micro-fine detail difference is of no matter to viewers who aren't aerial recon analysts),
You can see the effect I summarised in your results too - while the midtone gradient is being brought down to a reasonable level, the toe and shoulder remain very sharp - very much a fundamental function of the emulsion - and not something that process alteration is probably going to alter significantly. In the right circumstances it can be aesthetically successful. With neg/pos, it's possible to get round that problem more effectively (squeeze more on to the straight line), but for reversal it's a problem.
For the record, Ilfosol 3 is much sharper than Rodinal, and finer grained - but because of the heightened sharpness the grain is more visible than something like D-76.
Emulsion thinness is one of the biggest reasons that Kodachrome was as sharp as it was - those individual layers were very thin, for their time.
@miha, I'm curious if this thread answered your question? That is, based on what is posted here, or on your own experience -- have you decided which one of the three B&W Film Reversal Kits is best for you -- Foma, Adox Scala, or Bellini?
And if you have picked one as a favorite, what attributes were the deciding factors for you?
I'm afraid it doesn't. I'll have to search for the grail myself. I'm glad Henning shared his results with the Adox film and demonstrated how it best represents slide film.
Henning, I agree, monitors suck. This is why I print negs and project slides, and why I need to explore different combos by trying out several options.
And yes, I would be more than happy to meet a fellow photographer, whether in Germany or Slovenia, if the opportunity ever comes along.
Then there are really small rooms - like filling 1.75m screen from 3m distance and 90mm would produce half of that
Yes, Foma R100.
Looking forward to trying the film out. Any tips on what EI to use if it's different from the box speed?
I have just developed the first roll, rated at EI 100, and everything seems to have gone perfectly. I exposed the film using my Canon A1. According to Foma's instructions, gentle agitation is recommended, so I performed five inversions every 30 seconds. The temperature was closely controlled, though it was held at 21C instead of the suggested 20C.
For the second exposure, the film was on a white plastic JOBO reel, exposed for 60 seconds with a 150W opal bulb at a distance of 50 cm. So far, the results look great, and the film appears to have developed beautifully.
Update: I tried 3 films of the Scala 50 in Rodinal. 1+25 10 minute 22C semi-stand with a gentle turn at 5 minutes.Excellent, you've made me want to take out Scala 50 as my next film...
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