sorry for double post, I thought it was not posted correctly...
actually - a lot of the modern emulsions (Delta 100, 400, 3200, Neopan 400, 1600) have compressed characteristic and the developer used only affects intensity od compression or actual emulsion speed (measured on ISO standards).
older emulsions tends to be compressed too, but at higher densites (3-4) so it is extremely hard to make compressed image with them and to print it, of course.
If you operate the zone system the N-, N, N+ development along with the altered exposure values is quite a neat way of tweaking the curves.
I may finally have an advantage over you guys....
I'm a relative novice in the darkroom, only the last year, and I clearly see a different curve using different specific developers.
I mean the shape of the curve. Yes, CI defines compression but CI is just one form of average gradient, thus two different films with complete different curve shape can have same CI.
Originally Posted by keithwms
Now, having more time to study link I found something that actually shows what I am looking for: The shape of curve can be altered by developer. At least some degree.
Here's the APX-100 developed in FX-39:
And here's in Rodinal:
The overall shape of the curve is S with these developers, but with rodinal, the shoulder is much straighten than with FX-39 and TMAX. That is kind of differences I am looking for.
However, the really interesting is differences of middle tones - 'the straight' section.
Can it altered to be more unswept, or curved? According to new edition of the Adams's Basic Technique Of Photography Book 2 and various web sites - Yes. Mainly with HC-110 which gives unswept curve for films that usually has S shaped curve.
So far, it seems that Puts website cannot taken seriously. These all shows that curve shape is not entirely defined by emulsion of the film but developer also has own impact to it.
But how far we can go and with which film and developers? Can straight charasteristic curve (like curve of TMAX 100) altered to have both, more curved toe and shoulder?
This is interisting issue, I have calibrated lot of films for ZS, drawn charasteristic curves, studied them etc... But always with one developer + film combo. Never had time or interest to do same test for given film with another developer. Except one case: when I changed D-76 to XTOL, I had to recalibrate developing of some films, but with XTOL the shape of the curve didn't changed.
it is important to not overdevelop too much because you will get high density negatives with shoulder as like the apx100 + rodinal (you can be sure the shoulder IS there but far far away from easily printable range of the negative)
talking about this - friend of mine never had a problems with printing the lightest areas, never needed preflashing and other tweaks.... why?
everything on his negatives is straightly printable.... he uses delta 400 + dd-x at most. sometimes tri-x 400 in microphen od neopan 1600. nothing else at all.
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And any one of them, according to the manor in which
Originally Posted by Ian Grant
it is used, will allow for curve alteration. Dan
Here is an example of what Nicholas is describing. Same film, two different developers, similar gamma:
Originally Posted by Nicholas Lindan
In many cases, the differences are quite significant. Also note the differences in film speed for the various developers.
Rodinal alters the toe that much! That was new to me. Thank you!
(actually same information is on the on the chart's of the Foto Import site if I take my eye to the hand and look closer)
Now I have really something to study and test. Should even do some testing with my mostly used films with rodinal, xtol and pyrocat-hd. Then I will be wiser - I hope.
Last edited by Usagi; 05-25-2009 at 02:33 PM. Click to view previous post history.
How much can you alter the characteristic "curve" with developer?....
Mr. Puts is quite wrong, if this is what he meant.
Its possible what he meant was the "character" of the film is unchanged.
Originally Posted by Usagi
Last edited by dr5chrome; 05-25-2009 at 03:20 PM. Click to view previous post history.