X-Ray Film Testing

Gavjenks · Sep 9, 2013

Making a thread for a variety of tests I am starting to do with X-ray film. I've been playing it way too fast and loose with this stuff, and need to crack down and do serious comparisons and dial in the best methods. I figure some people out there may be interested in sharing the wealth of my findings.

For this first post, I am using Fuji RX-U Half speed blue 8x10 X-ray film, cut down to 4x5 pieces. It is available for sale here:
8x10 in. Fuji X-Ray Film for $0.00 in Fuji X-Ray Film - X-Ray Film - Analog X-Ray Supplies
A single 4x5 sheet costs about 8 cents.

I didn't want to have to rely on weather and sunlight, etc. and wanted to be able to do standard tests for a few days, so I set up a little still life scene, with representatives of every color, and some high contrasts. The white black gradient is obviously handmade with india ink. It should roughly represent 1-stop increments (mixed ink and water with pipettes), but you know, obviously just an approximation. Sadly I got it off frame in this first film test, but whatever. Plenty of high and low value stuff in the shot.

Here is the scene in digital color:

And the 4x5:

4x5 was processed with the best setup I have currently found for half speed blue Fuji film,
Which is 200 ISO, full stand development with D-76, agitate 1 minute, stand 40. (I know it's not made for that, but it works a lot better than standard, see further down this post. I am getting in chemicals tomorrow for actual stand developers, which should be better still).

Pretty damn good tonality, I think. Much reduced glowing of the highlights like I am used to from earlier processing methods. And you can still make out the gleam and writing on the lightbulb, as well as some details inside the shell and in the depths of the plant. Meaning this is nearly at the level of my 6D at ISO 200 (11-12 stops of dynamic range. Both of these are compressed tonally to fit a jpeg).

I turned various channels on and off and blended them, and figured out that the color sensitivity of the "half speed blue" seems to be most similar to an almost 1:1 mixture of the digital camera's blue and green channels, here, so it's similar to normal ortho film:

Why am I doing bizarre D-76 stand development? Well I ran out of the HC-110 I had that would have been the obvious choice, and my only other option on hand is ilford-DDX, and I was impatient. Tomorrow in the mail I'll be getting stuff to make obsidian aqua (an amateur designed pyro type developer) and will extensively test that. In the meantime though, I did the following tests with just D-76, prior to having set up my standardized still life:

D-76 agitated normally and shot at ISO 50 (6 minutes dev), 100(6.5), 200(7.5), and 400(9):
No processing done on these digitally

Clearly, either 100 or 200 is best. But neither is great. One blocks shadows still, and one blows out highlights quite a bit still. The light leaks are probably because I was using a flimsy jacket instead of my proper darkhood that I left at home, and/or had the film in an outside pocket of my camera bag, and/or loaded them lazily with a safelight =P

Since I was only planning on these, I didn't bring 4 more shots of film, but I did have two more, and decided on a whim to expose them at 50 and 400 for stand development. Here are sheets exposed at 50 and 400 both for 30 minutes semi-stand (one inversion at 15 minutes) D-76:

The 400 was great, better than the standard developments, but a little bit unnecessary on the contrast and a teensy bit too blocked up. So I just guessed 200 stand would be ideal + removing the inversion at 15 minutes. And the first shot I've done since then was with the still life you saw above, which turned out awesomely.

Disregard the dark strips on the left side. That was me not measuring my developer correctly and having to top it off (so the bit at the top of the tube developed a bit less at the start)

Next: The obsidian aqua tests, and I'm also getting in the mail some "HR-U Medium Speed Green." I'm hoping that if blue is actually ortho, then "green" might be damn near panchromatic. We shall see.

Gavjenks · Sep 9, 2013

The method for digitizing is with this setup:

An alienbees 400 is on the ground with a small softbox attached. Above, boards span two tables (leveled), and two panes of glass span that (fingerprints on the sides, but I make sure the imaging center stays clean every shot with microfiber). My 430 EXII flash sits there and takes the radio signal then triggers the main alienbees optically below. it doesn't go through the glass when I actually do it. That would be dumb. Off to the side a bit through air only.

I shoot with my 6D and a 50mm lens with 13mm extender tube if I want to just get a single shot capture. When I don't care about exacting sharpness (such as for these exposure and developing tests), I just lay the lens flat on the glass and then try to pick it up straight until in focus and shoot.

If I am doing actual archiving of decent quality artistic photos, I will break out the tripod and level the actual camera on it, OR use more extension tubes and spacers to actually be able to lay the camera right on the glass for perfect leveling.

With the tripod or flat on the glass, and additional tubes, I can get as high of resolution as the film seems to offer, pretty much (although it takes like 30 shots to stitch if you want the full monster 100 megabyte ridiculous version for plastering over your entire living room wall in a mural).

(That's just the modeling light)

Gavjenks · Sep 13, 2013

Okay, haven't done a lot on this, because I've been sick, but I ran some of the medium speed green film in Obsidian Aqua (pyro developer) with a stand development. Results of that are on the bottom of this image. Top is the D76 (stand development) Blue:

1) The color range of "green" and "blue" seems identical. *eyeroll*
2) They respond to developers almost the same (These aren't the same, but I ran other ones to compare, and they do. I am sparing you the boring images).
3) D76 stand development seems to work way better than pyrocatechol stand development??? More details in both the shadows and the highlights with stand D76, less glowing and bleeding of highlights. What's up with that?

I tried a variety of different concentrations/dilutions of the obsidian aqua.
1:1000 was too weak. It just came out underdeveloped, plain and simple.
1:750 was similar to 1:500.
1:500 (the recommended amount) is what you see above. Properly developed, but too contrasty. The opposite of what a compensating developer like this is supposed to do. I thought maybe if I diluted it more, the developer would exhaust itself more easily in the highlights and let the shadows catch up, but instead, everything just developed less. Not sure what else to do. I'm already agitating for only 2 inversions at the start and then not touching it for an hour.

Suggestions? Thoughts about why D76 could possibly be so much better compensating?

Also, by the way, here is a zoomed in shot of the shoe polish tin (the point I was focusing on), in the Green film obsidian aqua negative, versus my Canon 6D digital. This shows pretty much all the detail the film holds (I can take more magnified pictures but don't see much else new). The large format clearly blows the digital full frame out of the water, although not by as much as expected:

The little dotted liney patterns from the printer ink below "black" are especially telling.
These are both at f/22 with equivalent lenses, more or less (50mm full frame, 150mm 4x5, tin takes up a roughly equal portion of each frame). So diffraction is at play, and both lenses can do better, but still a pretty fair comparison.

Gavjenks · Sep 13, 2013

Aaaand I think I'm happy finally. D76 worked best, for whatever reason, for compensating. So I did some more runs with the D76 at various half stop ranges, and found 140 (halfway between 100 and 200) to be the most ideal. Then did a mostly naturalistic HDR of the negative to preserve maximum tonality. Final recipe:

Film: Fuji medium speed Green, but Fuji half speed Blue seems almost identical.
Shot at ISO 140
Developer: D76, diluted 1:3 (might try 1:4 later but whatever)
Agitation: few inversions then stand for 1 hour without touching
Fix with whatever and then scrub one emulsion with bleach
HDR in photomatix, fairly natural settings, -2 0 +2 of the negative on the glass light table
Sharpen