and good to know that we don't pursue figments of imagination but real differences in results.
Dan, such H&D curves are quite easy to make by contact printing a Stouffer wedge and exposing with a uniform light source.
BTW very interesting results you posted with Rodinal and Xtol, and good to know that we don't pursue figments of imagination but real differences in results.
Yes and that means you have actually got to print the negs at large sizes and measure the obtainable in print results otherwise its all theoretically achievable stuff which isn't the same thing.
If the light is the same for the step scale and resolution chart there is no problem.
A step wedge exposure as described above will give you no absolute ISO rating, but you can easily derive relative speed of one developer vs. the other.Printing a step scale to some slide film now with a film recorder, I'd do it directly to T-Max but I dont know what the light values exactly will hit the film for each step.
John, nearly every thread on every forum shows that most pretend to know the details of their materials. What's wrong with a handful of people wanting better information? It doesn't diminish their creative/artistic potentials in the slightest.
Rudi, if an exposure grabs the entire range of density on a chart, any chart, it will work with a step scale.
John, nearly every thread on every forum shows that most pretend to know the details of their materials. What's wrong with a handful of people wanting better information? It doesn't diminish their creative/artistic potentials in the slightest.
I'm still not clear on what you are trying to measure. Resolution or sharpness? Based on what I've read, resolution on its own is a relatively weak objective correlate to subjective sharpness - hence the acutance measurement, then edge effects, later MTF etc. Of course image structure (granularity, sharpness) can impact resolution to some degree.
If you make your own step wedge from exposed film, doesn't such a step wedge have its own granularity which creates incorrect results? I could imagine that especially weakly exposed regions of the target would respond differently to weak and uniform vs. grainy and weak on average exposure.
Oh I see what you're thinking... No. The step wedge is a separate control test. You check for exposure and processing by reading densities. You don't read granularity/graininess/sharpness/resolution from the step wedge exposure. Instead you include a separately-exposed resolution chart developed at the same time. The combination helps explain the conditions of your resolution test.
How do you measure granularity (or acutance) without a microdensitometer?
My scanner allows me to scan in raw mode, from this I can derive density and granularity data with a bit of image processing. As far as acutance and MTF is concerned, I am limited to the few dozen lp/mm that my flat bed scanner can reliably read. For Delta 3200, HP-5+ and Tri-X this shouldn't be a limitation.
For Delta 3200 I managed to hit 50-60 lp/mm off 120.
Exposed at 3200.
You can expose Adox CMS 20 and Pan F+ at EI3200 if you want, just don't expect much shadow detail. Since we know that Delta 3200 is ISO1200-1600 at best, but certainly not ISO 3200, it would be interesting if you gave us complete details for these 50-60 lp/mm result, and that includes ISO speed, either as absolute number, or relative to some well known developer.
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