Does pushing film reduce sharpness?

If I push Ilford HP5 to ISO 1600 by underexposing in camera and increasing the development time should I expect to see a noticeable decline in the perceived sharpness of the photographs?

I did an experiment and pushed a roll of Ilford HP5 to 1600. So far I have only scanned a few frames. I have not done a 1:1 test by shooting the same scenes at 400 and 1600.

And what were your results? I have never tested but have always assumed with increased grain size and contrast prints would show increased perceived sharpness.

By seriously underexposing the film, you're basically just lopping off most of your shadow gradation, so should expect to lose detail down there. But offsetting that with increased development will result in higher contrast in what is left over, so potentially more edge contrast up there. It all depends on the specific developer, degree of enlargement, and subject itself.

Creatively, hard to say. You might come up with a few interesting shots, along with some inevitable belly-flops. Have fun experimenting.

Paul Howell said:

And what were your results? I have never tested but have always assumed with increased grain size and contrast prints would show increased perceived sharpness.

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I'll share a picture or two over the weekend. I can't comment on the sharpness at all because I have concerns about my current scanning process or possibly my comfort with focusing on the new camera combo.

The most obvious thing I noticed is that I need to protect my highlights more next time. They are as hot as an oven.

DREW WILEY said:

By seriously underexposing the film, you're basically just lopping off most of your shadow gradation, so should expect to lose detail down there. But offsetting that with increased development will result in higher contrast in what is left over, so potentially more edge contrast up there. It all depends on the specific developer, degree of enlargement, and subject itself.

Creatively, hard to say. You might come up with a few interesting shots, along with some inevitable belly-flops. Have fun experimenting.

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I used Kodak HC-110 dilution B from concentrate. Most scenes were natural daylight. I did a few at night or in dim artificial light from fluorescents. I will expose more rolls before deciding whether or not to stick with it.

If I push Ilford HP5 to ISO 1600 by underexposing in camera and increasing the development time should I expect to see a noticeable decline in the perceived sharpness of the photographs?

I did an experiment and pushed a roll of Ilford HP5 to 1600. So far I have only scanned a few frames. I have not done a 1:1 test by shooting the same scenes at 400 and 1600.

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Oh yeah, just to be clear my question is about 35mm film.

No, I haven't seen a decrease in sharpness, but I do see a bit more grain, in that the more you push, the grainier the film gets.

Certain Exposures said:

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I used Kodak HC-110 dilution B from concentrate. Most scenes were natural daylight. I did a few at night or in dim artificial light from fluorescents. I will expose more rolls before deciding whether or not to stick with it.

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Isn't HC110 reputed to increase highlight contrast? If that is the case, maybe it's not the best choice for pushing in a high contrast situation. Also, night shots can be quite contrasty even though they look dim.

Certain Exposures said:

I'll share a picture or two over the weekend. I can't comment on the sharpness at all because I have concerns about my current scanning process or possibly my comfort with focusing on the new camera combo.

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OK, when you update that thread, please include the crucial information that you're apparently working with (deliberately) underexposed film.
Also, it'll be confusing if we have to discuss essentially the same problem in two different places. For now we'll keep this thread open on the premise that it asks a general question that's not restricted to the problem case you linked to above.

Certain Exposures said:

The most obvious thing I noticed is that I need to protect my highlights more next time. They are as hot as an oven.

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The only times I've had some problems scanning through dense highlights was/is when I work with negatives that are intensified beyond ca. 2.8logD using e.g. chromium intensifier for alt. process printing. This is so far beyond the density range of what you're likely to get processing film the way you've been doing, that I'll wager to say that your highlight problem is 100% down to a scanning problem.

As to your question about sharpness: most people push film when there's not enough light to work with. This means they'll generally work at large apertures and probably long(ish) shutter speeds. Hence, the odds are against sharpness from the get-go. Otherwise - no, I wouldn't expect that underexposed, overdeveloped film looks inherently less sharp than normally processed film.

koraks said:

...This means they'll generally work at large apertures (smaller apertures or higher f/stops) and probably long(ish) shutter speeds. ...

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Small correction -- bold is mine.

Vaughn said:

Small correction -- bold is mine.

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The actual aperture is large, so I don't feel it's a very fortunate "correction".

koraks said:

The actual aperture is large, so I don't feel it's a very fortunate "correction".

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I sit corrected...both are correct.

Certain Exposures said:

If I push Ilford HP5 to ISO 1600 by underexposing in camera and increasing the development time should I expect to see a noticeable decline in the perceived sharpness of the photographs?

I did an experiment and pushed a roll of Ilford HP5 to 1600. So far I have only scanned a few frames. I have not done a 1:1 test by shooting the same scenes at 400 and 1600.

Click to expand...

Yes, of course.

koraks said:

OK, when you update that thread, please include the crucial information that you're apparently working with (deliberately) underexposed film.
Also, it'll be confusing if we have to discuss essentially the same problem in two different places. For now we'll keep this thread open on the premise that it asks a general question that's not restricted to the problem case you linked to above.


The only times I've had some problems scanning through dense highlights was/is when I work with negatives that are intensified beyond ca. 2.8logD using e.g. chromium intensifier for alt. process printing. This is so far beyond the density range of what you're likely to get processing film the way you've been doing, that I'll wager to say that your highlight problem is 100% down to a scanning problem.

As to your question about sharpness: most people push film when there's not enough light to work with. This means they'll generally work at large apertures and probably long(ish) shutter speeds. Hence, the odds are against sharpness from the get-go. Otherwise - no, I wouldn't expect that underexposed, overdeveloped film looks inherently less sharp than normally processed film.

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Sure, I will note that I pushed the film in the other thread.

What's the minimum resolution should I post an image at for you all to evaluate? Here's one at the web resolution I generally use.



Please excuse the clutter.

Lens: Zeiss 50mm Planar F2 ZM, F2 @ 1/125.

Film: Ilford HP5 pushed to 1600 in Kodak HC-110 dilution B from concentrate.

Support: Tripod and shutter release cable.

Focus point: Focused on the word "Ilfostop."

Scanner: Plustek 8300ai. No sharpening.

Editing: I added contrast to my liking so you should not judge that here. I also did some burning.

I posted this related question on Reddit to see if I had unrealistic expectations about this particular lens or some other issue in my process.

Certain Exposures said:

What's the minimum resolution should I post an image at for you all to evaluate? Here's one at the web resolution I generally use.

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For black and white, I recommend resizing the image to a jpeg with 1200 pixels on the long dimension, and quality of 80.
For colour, a long dimension of 1000 pixels is better.

MattKing said:

For black and white, I recommend resizing the image to a jpeg with 1200 pixels on the long dimension, and quality of 80.
For colour, a long dimension of 1000 pixels is better.

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Okay, the image above is 1500 pixels on the long dimension and higher quality/larger than a 1200 pixel scan with a quality of 80.

Certain Exposures said:

What's the minimum resolution should I post an image at for you all to evaluate?

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Depends on what we need to look at. Generally for critical sharpness evaluations, it's best if we get to see an enlargement / zoomed in crop. So for instance if you scanned this at 2400dpi, a crop showing the sharpest area in the picture at 100% zoom level would be nice.

Right off the bat I'd say that your image suffers from minor focus and/or motion blur issues. The grain renders pretty much as you'd expect, suggesting the scan itself is probably fairly sharp. The unsharpness is in the image itself. Given the shooting conditions that's not a very odd occurrence.

I feel like people use "sharpness" to mean different things that are not always reconcilable. For example, concepts like edge acutance (or "micro contrast" whatever that is), versus resolving power. Like when Paul Howell mentioned with increased grain size and contrast, prints might show increased perceived sharpness, I think he's talking about the perception of sharpitude that comes from looking at an image with well-defined edges - a lot of midcentury journalistic B&W photography looks like this (perhaps Cartier-Bresson, etc). It's not blurry. However, such an image often doesn't resolve the finest details, in the resolving-power sense, so if you do the analog equivalent of pixel-peeping, it may not look "sharp."

Taking your image of the shelf in post #12 as an example: I didn't follow the whole scanning discussion or look for focus offset/motion blur. The grain in the darkish area of wall behind the Ilfostop bottle is fairly visible, I don't know if it's absolutely the sharpest lumpy grain (could be either the development or scanning). If I zoom in on the Ilfostop bottle, the finer text below "Ilfostop" breaks up. The grain isn't so easily visible because it's more of a highlight area than the wall. But it is breaking up in part due to the grains / limitations of the film. Both of these are more or less as expected from fast film that was pushed, ie underexposed and possibly overdeveloped.

I don't think it has to do with the lens, if that is what you were originally trying to test. If you took a similar picture on Tmax 100 (or Delta 100) at box speed and standard development, it would be 4 stops slower and you'd have to use a camera support, but the grain would be much less obvious and fine details would look different. On the other hand, if you took it with HP5+ at box speed in a pedestrian 6x6 camera (say a TLR) with a typical ordinary lens, the perceived grain would also be much less obvious. In both of those, you might be able to read the Ilfostop label. But if you have to do something like available light photography in a nightclub or performance space, neither of those might be sufficient. Resolving power isn't everything.

Moderator note: as indicated earlier, there's another thread going on about essentially the same problem. Because they now converge to the same example and people start to comment on this same example in multiple places, the discussion gets torn apart. Let's continue with the original thread here: https://www.photrio.com/forum/threads/sharp-on-the-light-table-but-blurry-on-the-scan.213925