I've been experimenting with the Kodak ImageLink FS microfilm that was discussed on the Submini mailing list earlier this year (2000). (Thanks to Jack DeLisle for bringing it up.)
In a desperate attempt to avoid paying $2 U.S. per roll to use the "official" Kodak Technidol LC developer, I've tried very hard to find a Don Krehbiel-style Rodinal soup that works as well with this film. (Also see Don's site for tips on using PMK "Pyro" with microfilm. Yet another thing to try!)
The images on this page should give you some idea of how Technidol compares to Rodinal when used on this microfilm, at least as I use them. Thanks to Denis Kermicle for sharing his Technidol tips. His discovery that ImageLink FS is much faster than other microfilms (E.I. 125!) persuaded me to give it a try.
For how I got to my Rodinal method from Don Krehbiel's recommendations, see OK, so Why 1:400?, farther down the page.
Note: Don Krehbiel recommends using 2.5 ml Rodinal concentrate (whatever the dilution) per roll of 9.2 mm film (probably OK for Minolta 16's, too). I rationalized using 0.6 ml in my tests because I only developed three or four frames at a time. You might need to use a much larger volume of solution to repeat my results with whole rolls.
To view the following images correctly, adjust your monitor as described by Don Krehbiel.
On the Left
5 minutes in Technidol LC; approx. 70° F; dilute and agitate as recommended for 35mm roll film.
On the Right
3.5-minute presoak; then 20 minutes in 250ml water + 0.6 ml Rodinal (about 1:400) + 1/8 tsp. Sodium Sulfite; approx. 70°. Invert tank once and tap (over about 2 seconds) on alternate 2- and 3-minute intervals.
|Photos ©2000 Marcus Brooks|
Both the above images were taken at about noon on a sunny day, 27 March 2000. I used a Minolta 16-II and my homemade yellow distance lens. The exposure was 1/125 at f/16 (E.I. 125). I scanned the JPEGs from 5x7-inch enlargements (not quite full-frame) that were printed on VC paper with a #2 filter. I used PhotoShop to match the screen representation as closely as possible to the original print. (OK, I confess, I also removed spots!)
On a 72 dpi display, the above magnification is about 8 times the original 10x14mm negative size.
To me, the Rodinal rendition's blocked highlights and featureless shadows are not quite as noticeable above as they are on the original prints. The following higher-resolution scans show the difference more clearly:
On a 72 dpi display, the above magnification is about 27 times the original 10x14mm negative size. If my calculations are correct, that's about equivalent to an 8x10 print, too large for me to make directly with my 50mm enlarger lens.
The awesome resolution of this film is emphasized by the following detail scans:
No, I didn't get the images mixed up. Although the Rodinal negative (right-hand image) appears to have a finer grain pattern than Technidol produced, this is simply because I goofed the enlarger focus. (Probably bumped the lensboard when I stopped down after focusing. Thanks to Don Krehbiel for spotting this.) I'll post a clearer print ASAP so we can see who's the real winner as far as grain is concerned.
On a 72 dpi display, the above magnification is about 120 times the original 10x14mm negative size. If my calculations are correct, that's about equivalent to a 4x5 foot print. Not too shabby for such a little camera!
OK, so Why 1:400?
Technidol gives extremely low contrast in its normal dilution, while Rodinal is a general-purpose film developer that typically gives normal contrast. But one nice feature of Rodinal is that you can get different contrast by varying its dilution. That's why Don Krehbiel can get such great results on high-contrast microfilms by using an extremely dilute (1:100) Rodinal solution (plus Sodium Sulfite) and infrequent agitation.
My trials with ImageLink FS ended up (gave up, actually) at 1:400, but I also tried 1:200 and 1:100 with various amounts of Sodium Sulfite. In this range, doubling the dilution roughly doubles the development time required. Even more dilution might continue reducing contrast, but I don't think the meager reduction achieved is worth the added development time.
As I understand it, slowing development is supposed to allow shadow details to fill in, while the depleted developer that accumulates over highlights effectively masks them. This effect is the reason for minimal, infrequent agitation. I settled on intervals of two minutes or more between agitation cycles consisting of only one tank inversion. If I were to continue, I would try adding a bit of Photo-Flo and leaving the tank inverted (film "dry") for various periods of time. Wacko notion, but it might work.
Don Krehbiel's use of Sodium Sulfite presents a mystery. My Photographic Lab Handbook says Sulfite just acts as a preservative for the developer. Don has told me it improves shadow detail and grain quality as well, so it also seems to affect development more directly. In my trials, a couple of strips showed fogging after I neglected to cut the Sulfite when I reduced the Rodinal concentration and increased development time. Using much less Sulfite seemed to correct the fogging; but that was never the only factor I changed, so the jury's still out until I do further tests.
Another detail: On his website, Don says he doesn't know why he presoaks for 1.5 minutes. Why did I go with 3.5 minutes? Well, while developing fully-fogged swatches with the light on (to find a starting point), I noticed that development starts much more evenly on a presoaked swatch, so clearly the presoak is a good idea. I also noticed that a large amount of blue dye streams off of the film while it soaks. With agitation, 3.5 minutes is about enough time for most of the blue dye to dissolve, so I take that as a sign that the emulsion is thoroughly soaked. I'm also uncomfortable with patches of dye clinging to the film as development starts.
So that's my experience with ImageLink FS and Rodinal. For general photography, I'm going to stick with Technidol for now. (Although I plan to try the Photographer's Formulary Tech Pan developer eventually.) But I'll also keep Rodinal handy for "personal microfilming" duties. In the dilution I use, it costs just pennies a batch!
Please drop a line if you have any comments or suggestions for this page, if you find it useful, or if you find the magic formula!
Back to Subminiature Cameras.
Marcus Brooks — 29 March 2000