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You can not develop Delta 3200 to match contrast of any film, because its characteristic curve is very concave, i.e. it has high contrast in weakly exposed areas and very weak contrast in strongly exposed areas. This weak contrast in strongly exposed areas will not go up with longer development times either. If your main subject matter is in the mid or highlight regions, you will have to print/postprocess to higher contrast. In this comparison the P3200 scan shot looks nicer because it has better contrast to match the scene, whereas Delta3200 scan shows much better shadow contrast.
If you increase Delta 3200 scan contrast to match the P3200 scan,
If you decrease P3200 scan contrast,
- Shadow regions may be shoved down to black
- Highlight regions will hold up because Delta 3200 is almost flat in highlight regions
- Grain will become more apparent
Could you please post raw non-inverted scans of these two negatives? This would allow us to look at shadow detail. Since most of us would use either film in low light situations, half a stop more or less sensitivity would be a big deal.
- Shadow regions which are now pitch black may show detail again - that's the big unknown here!
- Highlight regions will look more modest
- Grain will become less apparent
Ilford's Delta 3200 data sheet gives numbers for Kodak XTol, and for some Ilford developers the data sheet also gives characteristic curve and even C.I. plots over dev time. All these characteristic curves are strongly concave and by no means well approximated or represented by a straight line.I totallly disagree. I’m actually in the middle of generating a development regime for delta 3200 for replenished XTOL because Kodak does not have any published times for delta 3200 like they do for P3200.
You will have the same C.I. but different contrast in most areas of your image - your C.I. number is completely meaningless for Delta 3200.Kodak’s contrast index for EI 3200 is 0.72 for P3200 and you can in fact develop delta 3200 so that it’s contrast index is also 0.72 (measured exactly the same way as Kodak measures all contrast indexes). You may or may not get the same speed as P3200 at that CI, however, by that measurement regime, it will have the same contrast index.
You will have the same C.I. but different contrast in most areas of your image - your C.I. number is completely meaningless for Delta 3200.
You will agree that most film's characteristic curves have some straight section which covers most of regular subject matter except for deep shadows and strong highlights. Yes, there is a toe and a shoulder, but they are many stops apart, and in between there is a straight section in which you can establish a near constant slope and a C.I.That is the entire point. I’ve generated my own characteristic curves for most films available today for replenished XTOL and very few of them are actually all that straight. So, you pick a measurement standard and develop them to that same standard and look at the differences when developed to that standard.
Most films can be compared because they have long straight lines in their characteristic curves. Delta 3200 is the exception to this, and judging it with conventional procedures will do injustice to both the film and to your images.By your logic, no films can be compared because the characteristic curves don’t match. Yet somehow people have been evaluating films against each other for a lot longer than I’ve been alive.
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