help with a table (in persuit of high contrast portraits)

[lorriman]

I've found this rather interesting table that supposedly gives dynamic range numbers for various films. I'm particularly interested in this because my preferred type of portrait (in b&w) involves very high contrast. Here it is:

http://www.dantestella.com/technical/dynamic.html

However I can't interpret the table as I don't quite understand what this person is saying since I#m not strong on the technicals. Talk of contrast indexes and gammas makes my eye-balls roll up, my body to instantly assume a horizontal posture and then my brain reboots.

The table (at the bottom of the page) has two contrast index numbers for tri-x. Now obviously I would like to for the higher number for my purpose. What I can't work out is what that .58 number represents. Box speed, normal development? EI200, underdevelopment? What do you reckon?

Also perhaps you can tell me from your experiences of whether TMAX 400, with its supposedly astounding dynamic range, might be suited to my high-contrast portraits. I had thought that it was recommended for a 'controlled environment' which I had assumed to be non-high-contrast. I take pics with strong backlighting, with glowing highlights in the hair, but the one I am pursuing at the moment is sunlight through leaves on the face. To work that sunlight needs to be pretty muted. TMAX 400 the right one? As an alternative perhaps I should buy some perceptol (ilford HC is my only dev) and perhaps my cheap legacy pro might, just might, do the trick in that stuff. Any thoughts? Then again perhaps legacy pro is going for a premium these days and I should exchange it for some TMAX.

 

[Mike Wilde]

The scene you envision should be attainable, regardless of film, but there are other limitations to the results you seek that are not discussed in the linked document.

The linked document does mostly make sense, but it is a lot for even me, with an electrical enginering background, and a good background to understanding HD curves, to read without my eyes starting to glaze over.

You mention strong backlighting, with glowing highlights in the hair. This to me suggests a risk towards lens flare. Flare I think of as where 'non desireable' (sic) amounts of light bounce around in the lens system before depositing photons on the film. It can lead to density on the negative in areas where there was none intended my the image maker, and lowers contrast range one the negative by raising the level of Dmin.

A good lens hood, and certainly a coated lens will likely work best here. A multcoated prime lens may tend to lower flare than a multicoated zoom may give, due perhaps to the higher numbersof glass interfaces inherent in the zoom's design.

In such a situation, despite the desire for high contrast, you may want some fill flash to cut the contrast range, and give more definition to areas in shadow.

To reach towards a really high contrast image may need to lead to enlarged prints to lithographic film, developed as a postive, and then duped via contact printing to a higher contrast index enlarged negative. Without seeing the style you are reaching for, I am not really sure of the steps needed after the shooting, and then after the first film development steps.

I would sugest that just about any iso 100-400 film and developer can do what you want it to do.
Don't scamper off changing developers or film before you know what the pairing youn have can do.

Ilford HC is a 'clone' of Kodak's HC-110, and with varied dilutions can do many things well.
I would suggest working straight from concentrate to ensure a better chance at repeatable results from this long life liquid concentrate.
Look to 'covington innovations hc-110' for a good article on the technique.

I would suggest you research the late Barry Thornton's site about his personal film speed and film development times articles.

Don't fret about CI's. Figure what your materials can do using Barry's methods.

Then you will teach yourself that to fit the image onto the negative, and then fit it onto the print for a given contrast grade of paper in the tones you want, you are going to need to adjust your development time for different ranges of lighting situations when the image was first captured in the camera.

I aim to get full range results on grade 2 or 3 paper, and then have a range of lower and higher filter options available with printing paper (or scanned inage data) to manipulate the scen to higher or lower contrast interpretations.

 

[RalphLambrecht]

... What I can't work out is what that .58 number represents. Box speed, normal development? EI200, underdevelopment? What do you reckon? ...

A contrast index (CI) or an average gradient (similar measure) of 0.58 it very close to normal development. It means that a 7-stop range creates roughly 1.2 in negative density, which is about normal for a grade-2 paper.

The math is 7*0.3/0.58=1.2 since each stop is 0.3 in log exposure.

Remember that you can get a wide range of contrast out of film by decreasing exposure and increasing development time.

 

[ic-racer]

If these are portraits are in controlled settings, you should be able to easily adjust the lighting to get a range less than 12 stops. All the brand-name film will exceed the range of most subject matter. The cheaper slow film on the market can have a limited range in some settings ( like reciprocity failure in the shadows.)

 

[lorriman]

Thanks for the info, everyone.

"Remember that you can get a wide range of contrast out of film by decreasing exposure and increasing development time. "

Is that right? I'm reading everywhere else that it's the other way around for extended contrast: over-expose and under-develope. Evidently that may not help my purpose since it should decrease the chance of having muted sunlight highlights (more true of 'shouldered' than 'flat' film?), and so your strategy may be the one. But I'm interested as to how you seem to have the opposite view of everyone else. 'Everyone' being random bods on the web.

 

[RalphLambrecht]

... your strategy may be the one. But I'm interested as to how you seem to have the opposite view of everyone else. 'Everyone' being random bods on the web.

This is often the case but surely not this time. I'm in pretty good company on this one.

...I'm reading everywhere else that it's the other way around for extended contrast: over-expose and under-develop. ...

Let me 'translate' this one for you:

for extended subject contrast: over-expose and under-develop to reduce negative contrast.

As any Zone System book and practitioner will tell you, reducing exposure and increasing film development time will increase negative contrast and visa versa. To deal with a high contrast scene, you do the opposite, increase the exposure and reduce the development time.

You'll find examples on how contrast increases with development time here:

Dead Link Removed


This is a table of my favorite films and their development times in Ilford ID-11 or Kodak D76 for subject brightness ranges from N-3 to N+3. The corresponding film speeds are listed here:

Dead Link Removed

Depending on your development equipment, materials and processes, these values may change. Consequently, they are only offered as a starting point for your own evaluations, but the trend is clear:

Decrease exposure and increase development time to increase negative contrast.

 

[markbarendt]

lorriman

If the scene (your portrait setting) "looks" like what you want then you should be able to get the result you want from most any film. That is essentially a lighting and posing issue, not a film issue.

What used to be very confusing to me was how contrast is discussed vs. what I was trying to say/get.

A 17-stop scene is a "high contrast" scene. There is a big difference in brightness between black and white.

Many, if not most, of the portraits I like require only 5-stops or so of detail. Beyond those central 5-stops I just want a smooth quick transitions to white or black with hints of detail. This is a low contrast scene because there is not a big difference between black and white.

Negative film is a an intermediate medium, its curve means little to nothing without the paper.

Paper white to paper black is nowhere near 17-stops, it's closer to seven.

To print 17-stops of detail as a straight print on paper requires a "low contrast" print, big differences in brightness in the original scene are translated into small differences on paper.

To print a 5-stop portrait on 7-stop paper the opposite happens, smaller differences in scene brightness are translated into larger differences on paper. Print contrast is stronger, higher.