Thanks for your input Roger 🙂
Ehhh do you mean overdevelop rather than overexposure?
The sample I have seen also shows the combo's between over / under exposure and over/under development...
No: exposure. Overdevelopment has a similar effect but normally considerably slighter when it comes to sharpness and grain, though some films respond much worse than others, especially where big grain is concerned. EDIT: Of course more development also gives a higher Dmax: I just added that because I realized I'd misunderstood your question, mostly because I don't scan small negs (I scan 8x10 occasionally).
Obviously there are 9 possibilities, compounded of over-, optimum and under-exposure and over-, optimum, and under-development. Over/Over with be contrastiest, densest, grainiest and least sharp, and Under/Under will be thinnest and least contrasty, but it
may also be sharpest, if the contrast of the test target is sufficient and if the lens is adequately contrasty.
The trouble is, tonality can fight with all of them in different ways, so there's never an absolute optimum film speed or development time that is good for all subjects at all times. Many photographers prefer more exposure, and take the hit on grain and sharpness. Indeed, many LF Zonies have to take that hit, because they always overexpose as a matter of course: they're saved by the inherent latitude of neg/pos photography, especially when it comes to a stop or two of overexposure, rather than being as precise as they think they are.
There is also a popular internet myth that manufacturers' dev times are
always too long, though in the words of a manufacturer's spokesman, "Why would we do that? Spite? Do people think we WANT them to get anthing other than the best results of which our materials are capable?" Yes, many find they're happier with shorter dev times -- but others find they're happier with longer ones.
Being intimidated into under-developing because that's what "the experts" do is on a par with always trusting your exposure meter implicitly, at the box film speed, regardless of developer. The best negs are the ones that give YOU the pictures YOU like, and I firmly believe that the only way to do that is by simple, iterative testing.
Bracket to see which exposures work best (+/- 1 stop will do to begin with, though you can narrow it to +/- 1/2 stop or even +/- 1/3 stop later if you like) and vary your development times by +/- 10-15% to see which negs print best: they should still be eminently printable at either extreme.
To make them 'read' after photomechanical reproduction, the sample negs in books are typically
at least +/- 1 stop on exposure (and the 'over' may be 2 stops over), while dev times may be -25%, +50%
or more.
It's an exercise worth doing for yourself, but I grievously doubt that you can learn much from pics in books. They are at best a way to help you visualize the differences qualitatively, but I really don't think they are much use qualitatively.
Cheers,
R.