B&W- looking for the sharpest image

[matan_levinson1]

many good answers indeed. just to make things clear:

 

so far I've concentrated on landscape photography, using the best products money can buy- velvia film, canon prime lenses, a sturdy tripod, mirror lock up, and of course- the best lab around.

 

about a year ago I've started doing photojournalism and decided I want BW for that.

so far I've used agfa apx 100 and 400 iso, kodak tmax 400 and 3200 iso. I develop the films in a BX developer (1:14, 20c) and print on agfa mc premium paper. I hate to admit that I don't know what enlarger and lens I'm using, since it's not my own darkroom. I don't even know if it is well alligned.

 

obviously I have alot more to learn about B&W photography and darkroom workflow! I never knew BW could be THIS complex.

 

now I have ANOTHER question:

I understand that picture sharpness is compiled of several factors like acuteness, grain, tonality, and maybe more stuff. what are those? how do these factors affect on the image and on each other?

 

again, thanks foryour answers,

 

matan

[dhananjay_n]

As mentioned above, sharpness is a term used to indicate a subjective experience. Objective correlates of sharpness that are typically used are resolution and contrast. Resolution is the ability to resolve finely spaced detail, typically measured by photographing a test target consisting of alternate black and white lines of varying spatial frequency (i.e., size) and expressed in line pairs per mm or lpmm. Contrast refers to the slope of the line dividing different density areas i.e., whether the resolved 20 lpmm is a fuzzy 20 lpmm or a crisp 20 lpmm - is there a black line that abruptly shifts to white or does the black line go through a small area of transitional grey before changing to a white line. MTF graphs are often used to summarize both aspects of an optical system in one graph.

 

Both acutance and contrast are affected by myriad factors - format, lens, lens-to-film distance, film, developer, technique etc etc.

 

Touching on only the format issue, there are obviously multiple things that differ across formats. But as far as the sharpness issue goes, the math is very much in the favor of bigger formats (with a couple of caveats, touched on later). The typical figure quoted for human eye resolution is somewhere in the region of 10 lpmm. So, that is what you need on the print. If we assume an 8x10 print requires about a 6-8 X enlargement from a 1"X1.5" 35mm negative, this means that you need at least somewhere in the region of 70 lpmm resolution on the negative (and this is assuming that you have no losses at the enlargement stage which is an impractical assumption - so, for practical purposes, you are talking about needing something like 100lpmm on a 35mm neg. This means using good lenses (which are typically expensive) and having spot on technique every step of the way. And things get even messier if we listen to analyses by some folks (e.g., Ctein) who claim that including the contrast function in addition to the resoltuion ends up increasing the on-print performance to as high as 30 lpmm (i.e., less that 5-10 lpmm looks plain unresolved, betweeen 10 and 30 lpmm, the human eye can make out a difference between a high contrast 20 lpmm and a low contrast 20 lpmm - a gross oversimplification but it sort of gives you an idea). Larger formats do suffer from a couple of drawbacks in the sharpness sweepstakes. The first is ensuring that the ground glass and film plane occupy the exact same position (most LF cameras do not utilize a pressure plate like 35mm and MF cameras do). Second, larger formats use bellows stretched out and this can act like a sail in the wind and introduce shake more easily as compared to metal housings. But all said and done, the math favors the larger format, especially if yo work carefully and methodically.

 

The issue of gradation is a very valid point as well, but I think it a little different. If you do not exceed the enlargement potential of a negative, it is unlikely you will detect a difference in sharpness per se. For example, an 8x10 enlargment from a 4x5 neg is not going to look less sharp than an 8x10 contact print from an 8x10 neg - the human eye will, in all likelihood, be unable to tell a difference in resolution. However, many folks suggest that the contact print has an image that is more 'lifelike' - I suspect that this is related to the notion of gradation. Gradation is a somewhat vague term in the literature but I think it refers to a combination of local contrast and overall contrast. And it is here that the advantage of a larger format is most visible. Think of it this way. Microdetails and microgradtion are captured with less grains of silver in a smaller format. So, as you enlarge this to a greater amount (than larger formats), the first thing that you are likley to notice is the structure of the image breaking up - enlarge too far and grain start becoming apparent but even without going that far, it is possible to detect the difference from having more information in the larger formats. Small gradations are captured with greater fidelity in larger formats because of this. A difference in luminance in a small area is captured with more silver in a larger format film. At the limit, you can imagine a small film that has light from this entire area (that actually consists of small differences in luminance) falling on just one silver grain and will thus produce just one shade of grey rather than the actual differences in luminance that actually exist.

 

The choice of format is a pretty personal choice but Dan does make a very good point in that good 4x5 systems are among the most affordable ways to start making really high quality photographs. Smaller formats do require equipment that need to operate at higher tolerances and that is an expensive proposition. Not that it can't be done with smaller formats, but it is done easier and cheaper with larger formats. Caveat: As mentioned before, format choice is pretty personal stuff and sharpness isn't all that matters etc.

 

If you do want to use 35mm, the way to go is probably to use a technical or document film like Tech Pan coupled with an appropriate developer to control the inherently high contrast these films develop to (lots of options for developers that can yield pictorial gradation from these films - POTA, POTA modifications, Technidol, and most acutance developers should work). You will have to work on a steady tripod, use first rate lenses, use mirror lock-up to avoid vibration, develop carefully etc etc. If you insist on using an 400 speed film, it is going to be an uphill battle. Grain and resolution tend to be more problematic with films of this speed in 35mm, especially if you are enlarging to 8x10 sizes.

 

Cheers, DJ

[jorge_oliveira2]

It may be a completelly lost shot - but with your unknown enlarger/lenses that may be the real problem...

 

Try to get a good loupe (a wide angle objective - 28mm or less is very good used backwards - you point the camera side to the neg) and look at the negative.

 

Is it sharp, good detail contrast?

 

If so, you need a better enlarger/lens.

[ken_schroeder]

I agree with Lex about choosing one film, developer and paper and really learning how to use it. I settled on Tri X and HC110B twenty some years ago. I doubt it is the sharpest combo, but it has served my needs well and allowed me to concentrate on making images.

[lex_jenkins]

Ditto. I used nothing but Tri-X and HC-110 for years until I knew everything that combination was capable of between EI 250-1600. Only after I quit the photojournalism field did I expand my use of materials.

 

I'd still like to settle on one fine grain film, one fast film and just one or two developers for all purposes. But the subjects I photograph and styles I explore defy this effort at Spartan photography.

[MTC Photography]

Try http://www.gigabitfilm.com or Agfa Copex Rapid Pan + SPUR NANO Speed developer combo from J and C photo

[MTC Photography]

Agfa Copex Rapid Pan developed in SPUR or Rodinal is sharper than

Kodak Technical Pan developed in Rodinal. <p> Copex/SPUR combo provide the sharpest rendering of finest detail, not possible with

any other known film/developer combo.