methods for more contrast???

[Q.G.]

Of course it does, but I think what 2F/2F is saying is that on camera filtration doesn't change the slope of the film's characteristic curve, and that's an important distinction to point out. [...]

It is.
As long as it is clear that Monophoto was right.
What we're after (unless we aren't photographers) is a picture that looks different, more contrasty. That can also be achieved by filtration.

 

[markbarendt]

So you were addressing what aspect of any of the methods mentioned exactly?

Reducing exposure reduces negative density, potential contrast is lost.

The highest contrast available is when the film's curve is full. This provides the greatest total contrast. The straight line portion of the curve provides the largest tone-to-tone separation/contrast.

When less than the whole curve is used, contrast is reduced. Midtones slide onto the lower contrast toe, shadow details that were on the toe drop to black, and the white point gets closer to the black point.

To be able to use the whole film curve reliably, we need to test. We each need to define for ourselves where the limits of each process are and how our metering relates to that or we won't know what we may be giving up.

Once I define my limits and EI's for my film/development combos, I will have the tools that can help me reliably place a specific SBR on a specific film curve.

Barring a tested understanding of the limits of my films, if I just want a bit more contrast from my film, all I need is a bit of over-development.

You and I don't know if anyone reading this is actually exposing their films fully. For all either of us know, their problem with contrast may be that they are underexposing; not filling the curve.

Given that, simply falling back on the old rule of thumb of advising an underexposure hard coupled with over-development may mean that the reader ends up with both a loss of shadow detail (things they might not want to lose) and a loss of the overall contrast (that they were looking for).

Leaving the exposure setting alone doesn't pose the same problems. Overall contrast may go up, shadow detail will be maintained, contrast between the shadow tones and mid-tones will increase.

The only question is if the highlights will fall at an acceptable point.

 

[Q.G.]

Mark,

You keep arguing against things noone suggested.
You assume you do things with due care, but noone else does.
Wind mills, 'ey?

 

[fschifano]

Actually, different wavelengths do change the contrast somewhat. It's a little known phenomenon called the Gamma-Lambda Effect. Shorter wavelengths (blue) produce lower contrast. Wavelengths toward the center (green) increase contrast, and longer wavelengths (red) have more of a neutral affect.

Of course, Gamma-Lambda Effect isn't the reason we use color filters when shooting B&W.

Interesting point. It's something that I'd suspected, but never knew what it was called. I did a little bit of poking around and came up with Dead Link Removed. The author makes the distinction between ultraviolet and visible light though, and that's not quite the same as the comparing the results from one end of the visible spectrum against the other. I suspect that the differences are far less pronounced across the visible spectrum.