8x10 photography and diffraction

[StuartR]

Thanks Pere,
I use an iQ Air HEPA filter. It does indeed help, but the more handling, the more problems, unfortunately.

If you see dust, let me recommend something:

Attachment 192274

An HEPA class air purifier is an smart solution, just start it in a clean room some 10min in advance before loading holders, drying negatives, scanning, darkroom printing or manipulating negatives. It removes very small particles (see wiki HEPA) in the air so it's used by people with allergies.

I use a Honeywell 16200, but any other HEPA purifier for home should work great.

[Drew Wiley]

If even basic dust control is still an issue, it's pretty much a waste of time to be nitpicking all these other issues.

[ic-racer]

I am wondering what the real "best" apertures are for 8x10 with very large enlargements

Use this information to determine the sharpest aperture for a plane of focus: http://www.hevanet.com/cperez/testin...0mm_and_longer

Compare to this information to determine the sharpest aperture for a 3D subject: https://www.largeformatphotography.info/fstop.html

Taking those data into consideration it frequently would be f 32 for me.

If you are an artist, rather than a technician, throw all that out the window, stop down to f90 and shoot some "Cape Light" and be famous.

[Vaughn]

... I do think 8x10 will be more of a camera for ideal conditions, rather than one for constant use. For me it seems to come into its own in portraiture or rather flat landscapes (assuming I want the whole landscape in focus!). I will stick to 4x5 and 6x7 for the more dynamic and three dimensional compositions....

The 8x10 is my main format...flat landscapes are a rarity for me...3-D landscapes being usually what I face (most of my work is either in the Redwoods or "non-grand' landscapes in Yosemite). It takes a lot of patience, practise and perservence. Fortunately, I only contact print and generally do not have to consider diffraction, so f45 to f90 are my friends, although the need for very long exposures can be frustrating. When I do photograph a flat landscape, I am thankful for the ease they present in using the 8x10.

Vibrations in one's set-up and/or wind moving the camera are also sources of a lack of sharpness. I have never done it, but putting a laser pointer on your camera and checking out the amount and length of vibrations sounds like a good idea to try if a lack of sharpness with the 8x10 continues to be an issue.

Best of luck and enjoy!

[Drew Wiley]

I find all this obsession about grain and ideal aperture largely impertinent. There are bigger fish to fry when mastering 8x10. And the idea of jumping into an entirely new learning curve and cornucopia of complications with a fancy digital back -why? If you want to save money on film or prefer an all-digital workflow, I'd understand. But trading worries about 4x5 grain versus the inevitable loss of detail in oversized digital capture just doesn't add up. Film grain itself could be softened post-scan if that is the effect one desires. I don't even know if it's b&w or color imagery in question. But people going back and making comparisons with extinct Super-XX film, which had grain the size of buckshot, makes no sense in this era of films like TMY400, which gives you very fine grain along with high acutance and superb tonal linearity and control. But I've seen mural sized work done from even good ole Super XX that was truly eloquent.

[Drew Wiley]

Now let me explain this from an entirely different angle. 8x10 photography inherently involves depth of field compromises. Crunching numbers will only take you so far. You need to learn how to strategize depth of field in a compositional sense, intelligently, for sake of the specific image itself, rather than rely on rote formulas. Some scenes might be amenable to very crisp overall plane of focus control, especially if wide angle lenses with their greater depth of field are involved. But in most cases, I find myself prioritizing certain things in the picture which I want the viewer's eyes to instinctively focus upon within context of a much richer cumulative print. I often do this by carefully nuancing the critical focus. Please do not confuse this with the notions of either soft focus or what small camera tele-photographers term selective focus. It's a lot more subtle, but allows me to strategize big highly detailed prints. Nothing is more disconcerting than these new huge digitally stitched panels where everything in the scene is artificially equally sharp. Human vision does not work like that. Vermeer would roll over in his grave. The eyes survey, select, re-focus, and prioritize; and any intelligent composition should assist that process.

[Vaughn]

Excellent points, Drew, but I also take into consideration not just how we see, but how we process that information and store it (memory). Most of us (or at least I) do not remember the out-of-focus parts of the 'gestalt' image created by our brains, and a print as a 2-D surface does not easily allow us to recreate the same process as viewing the scene in person. However, I agree that being aware of the process with which we see, and how we create mental images and memory can be an important part of one's creation of photographic images.

An aside: I have made 16x20 silver gelatin prints from 4x5 Super-XX -- I do not remember large or objectionable grain. But then, I think I developed it in Microdol-X (1:3). I'll have to track down a couple of those prints and refresh my memory...that was back in 1987.

[Jac@stafford.net]

Grain is my friend. It promotes accutance.

[Drew Wiley]

Hi Vaughn. I've often watched how even the otherwise uniformed public reacts to my large prints. I want to lead them in, over and over again, to discover new things, whether viewing from a distance or right up close, but in a prioritized manner so that the compositional flow is itself at least subconsciously absorbed. It hate the instant "gotcha" mentality of big prints today, similar to advertising billboards. But if you want a good debate over the psychology and physiology of vision, too bad my aunt isn't still alive as both a famous muralist and professor of art history. She was dialectically adamant how the world should be viewed, totally outspoken, and taught it. "The eye always rolls itself clockwise when taking in the world". That kept the experts and pontificators constantly at odds among themselves hypothesizing what made her own work so effectively two-dimensional. They didn't even know she was blind in one eye and actually saw things that way!

[Jac@stafford.net]

Hi Vaughn. I've often watched how even the otherwise uniformed public reacts to my large prints.

We of this forum are the uninformed because your work is entirely absent.