Original Perfection XR-1 Formula?
by Ed Buffaloe
It has been pointed out by various folks on two photography forums that U.S. patent number 4083722 may well be a precursor to the Perfection XR-1 formula, which is no longer commercially available. XR-1 claimed three
uses: (1) contrast control and compensation, including for extended range night photography; (2) development of fine-grain films (such as Agfapan 25, Kodak Technical Pan, Kodak High Contrast 5069 and 5369, and various
microfilms) for extreme enlargements with minimal grain; and (3) push processing any film from 1 to 3 stops. It is described as not being a fine grain developer, but as being capable of increasing the effective speed of any
fine grain film.
I found a web post stating that the June 1981 issue of Darkroom Techniques magazine has an article on XR-1, and the December 1982 issue has an article that compares XR-1 with Technidol and FG7. Unfortunately, my collection of this magazine only goes back to 1984, but I will try to obtain copies of these articles at some point.
In Bruce Barnbaum’s “Master Printing Class” in the November-December 1996 issue of Photo Techniques he describes a method of using two developers, XR-1 and very dilute HC-110, to develop Tri-X exposed in an extremely high-contrast situation (11 stops). In this situation he could not use a long exposure but still wanted shadow detail, so he used Perfection XR-1 (for 1.5 minutes) to get the desired shadow detail, then followed it with dilute HC-110 (for 8.5 minutes) to prevent the high values from overdeveloping.
It looks as though William A. Anneman, who holds the above-mentioned patent, may have started with the POTA formula, adding both metol and hydroquinone for their superadditive effect, as well as a tiny amount of borax as an
accelerator. He then worked out appropriate dilutions and temperatures for various films. The XR-1 instruction
sheet states: “Stock solution has a pH of 7.7.” The patent gives two variants (I’ve included the POTA formula for comparison):
I finally tried the XR-1 formula yesterday. I prepared the “A” solution as listed on your site, except that I dissolved the Phenidone in anhydrous Isopropyl and kept it in a separate 1% solution rather than mixing it into the stock solution. Then to prepare the developer I add stock Phenidone solution and fill with water. I used the processing notes from the data sheet, diluting 1:7 and processing for 13 minutes at 30C, as is recommended for Kodak Tech Pan at normal speed and contrast. The film I used, however, was the most recalcitrant microfilm stock I have, Fuji HS-U, exposed at ASA 64 in a 16mm Kiev 30. In this case I diluted the stock solution in tap water, which is relatively alkaline this time of year in our neighborhood, about pH 7.6. So this was a good test of the buffering properties of the formula.
The results are pretty remarkable. HS-U normally gives zero shadow detail more than 1.5 stops below dead center and saturates about 1.5 stops above, making for a nearly unprintable negative even when the mid-tones look plausible. These negs show good shadow detail, which I suspect will print pretty well since the film base on HS-U is almost completely transparent. The mid-tones are absolutely lovely to look at through a magnifier, and there is no trace of blocking in the highlights.
The only comparable results I've seen for HS-U have been with David Foy's formula for H&W Control developer. That formula may give a bit more speed (maybe a half stop) but judging purely from the negative I think the XR-1 version may print better. I will send another note after I've had a chance to print these. And then to work out the details, and on to push-processing Efke 25...
A couple of additional data points since the first message.
1. I printed up some of the Fuji HS-U microfilm negatives and they were, as inspection suggested, very useable.
Extremely smooth tonal range, no blocking in the highlights, and consistently printed at contrast grade 3 on Ilford
multigrade RC, using a dichroic head on an old Rollei enlarger. One of the prints, a 5x7 of a Eucalyptus tree in direct sunlight, is as pretty as anything I've done lately. And this is from 16mm.
Forest scenes with wide brightness range, from direct sun on bleached wood to deep shade. Pan F+ Exposure at ASA 100 estimated with Weston Master and experience. Variety of 120-format bottom-feeder type cameras, but with consistent shutter performance.
XR-1 prepared as two stock solutions. “Solution A” is the formula (version A) on the web site, but leaving out the
Phenidone. “Solution B” is a 1% solution of Phenidone in anhydrous isopropyl. This combination appears to have
excellent shelf life and is trivially easy when it comes to dissolving the Phenidone. I measure out A, add enough of B
to include the right number of mg of Phenidone for the volume of A, and then dilute to the final working volume with
distilled water. Then heat to 30C in a microwave oven. (note: the formula appears to function just the same with pH 7.6 tap water replacing the distilled water.)
I never used the original XR-1, so I have no basis of comparison with the original. But I can say that this formula
does in fact deliver a very solid ASA 100 on Pan F+, and gives beautiful negatives with excellent shadow detail. I
intend to continue using it. I think I would do so even if I hadn't already fallen in love with its results on my various microfilms.
Experiments with Pan F at ASA 200, Efke and J&C Classic films (because I use their sheet film in cm sizes. I know, I know, bottom feeder.)
I have found reasonably good developing times for XR-1 diluted 1:5 to produce ASA 100 (12 minutes at 30C) and ASA 200 (20 m at 30C) results on Efke 25. Using a 1:2 dilution for 20 minutes seems to produce speed considerably in excess of ASA 200, but I didn't experiment with it enough to quantify it. Comparison to the results with PanF Plus is interesting. First, Efke 25 doesn't appear to lose shadow detail as quickly as PanF when it is pushed two stops or more. The negatives at all speeds are quite visually pleasing, without either blandness or excessive contrast, and without the growing areas of zero density that PanF shows at ASA 200. This is not at all quantitative, but PanF gives the impression that it resists being pushed, losing maximum density and shadow detail both as you push harder. Efke doesn't. In fact, its maximum density appears to increase as you push harder. Second , unlike PanF, which seems to maintain its fine grain structure no matter how far it's pushed, there is a quite visible difference in grain size in Efke 25 as it is pushed harder. Grain at ASA 100 appears about the same as PanF at 100. But at ASA 200, the Efke material has considerably coarser grain structure. It is coarser again at the 1:2 dilution I tried. This does not seem, interestingly enough, to impair resolution or apparent edge sharpness. It is only visible in diffuse areas of the image.
I've been trying the XR-1 formula A with Efke 100. Again, wow! Developing 1:5 for 14 minutes appears to give a good, solid ASA 200 with remarkable deep-shadow detail on direct sunlit subjects, and very fine grain. Grain is quite invisible in 5x7 prints from 35mm. In an 11x14 print, the grain is visible in diffuse areas of the image (if you look closely) but to my taste is just below the point of being intrusive into the apparent surface textures of objects in the picture.