Originally posted by Vertex Ninja In the end, these photos can't really tell us all that much anyway. Since they are digital files, who knows what's been done to them or how they where scanned. In a blind test of various images I'd be hard pressed to pick what was developed with what, and this goes for any images I post too. I think it's best to test Yourself where you know the workflow will be the same or at least similar; the differences are much easier to spot then.
Edit: I do like how Sandy King and other BTZS users test film/dev combos. A characteristic curve removes the scanning and processing variable, and makes any differences in effective film speed and contrast clearly visible. Too bad a curve tells you nothing about acutance or grain pattern.
Very true, though you can't make a silk purse out of a sow's ear, not even in PP. Blown highlights are generally not fixable and neither are zero density shadows. No data = no data. When evaluating images from a particular film and developer, I look for:
- how the density extremes are handled
- tonality in the midrange
- grain (hard to gauge without the negative in hand)
- acuity
A person might argue that the last point can be made up in PP, but my experience is that this is hard to do with artifact.
Probably the best evidence I can offer for seeing the impact of processing on final image qualities is to look at some of the excellent pyro and stand/semi-stand work that is regularly posted on this forum. Those images all bear the hallmarks of the techniques that produced them and are hard to duplicate using other than those techniques.
As for Sandy King and the BTZS crowd...They do excellent work and you can approximate their process for fine tuning your own flow. For accuracy's sake, I would point out that the characteristic curve is nothing more than a plotted scan of a "density wedge" and that processing details (developer, time, temperature, and agitation) determine the shape of that curve for a particular film. Being able to see the curve is nice, but not essential since you can accomplish much the same thing with a standardized target subject. One of these days I should post an article here on how to determine development times and EI for a particular film/developer combo using common objects and direct examination of the negative.
The role of the scanner and PP is analogous to traditional darkroom printing, but has advantages due to much more flexible controls for handling contrast.
Steve