pH change in PC-TEA ?

[gainer]

Now what do you do with a contrast index of 1.2? Somewhere around 0.6 is normal in my darkroom. If you reckon film speed by density above B+F, it varies with C.I. but if you reckon it by the point where local contrast gives usable shadow detail you get less change with contrast. I do not usually mention film speed because I do not have the apparatus to be sure I know what I'm talking about. I set my exposure meter according to "box speed" when I make my test exposures.

The difference between 400 and 640 is about 2/3 stop. Acceptable manufacturing tolerance is 1/3 stop give or take. The box speed is supposed to be the nearest 1/3 stop to the actual speed. What do we argue about? I went through all this years ago because I was taking pictures on stage at orcheatra rehearsals and wanted the max. I found more effect of meterings than of any other source of variance in the results, and I tried just about every highly touted speed developer on the market. I finally settled on my own concoction of phenidone, hydroquinone and sulfite and setting the on-stage exposure at 1/60 and 2.8.

The digital age has taught me a lot about shadow detail. I have some negatives I cannot print any other way. They are so thin that the only way you see the image is by glancing reflected light as a positive. You all have seen such disasters, I'm sure. I know the shadow detail is there because my scanner told me so. As far as I know, no one makes grade 10 paper, but my scanner and software make it aout of typing paper. Don't get me wrong. I'm not a heretic. It's only for those pictures I must have that I resort to such reprehensible shenanigans.

Some of those thin negs have been rescued by intensification through bleaching and redeveloping in a pyro developer. The silver image is restored and a stain image is added to it.

I wander as I wonder.

 

[gainer]

Repeating one of my posts at photo.net:

I tried 2PC-TEA 1:100 on Tri-X as well, but this time with two tbsps of sulfite per liter. At 76F, 8mins, it gave ci of 0.9 at a staggering speed, probably 800 ASA. Full developed to a ci of 1.2, the speed is going to be whopping. The grain is quite big for Tri-X, but sharpness is not too bad.

I should have said this before I wandered. Show us the family of curves for several different developing times so we can guess how much of the speed increase is due to contrast increase. Also, my film was HP5+ and was shot at 400 by my meter, which may or may not be accurate.

 

[psvensson]

I'm sorry, the figures aren't contrast index. It's zone VIII density minus zone I density. I aim for a range of 1.25 for a diffusion enlarger.

I know, measuring shadow speed is iffy, and my results can be regarded as anecdotal. But they're shot with the same camera and I find the results fairly consistent. There's nothing to say that you will get the same density I do when rating a film at a particular speed, but I feel fairly confident that increasing phenidone increases shadow speed. Especially in the case of the Tri-X test I mentioned above, there was almost a 2-stop increase in speed as compared to straight PC-TEA.

 

[psvensson]

Show us the family of curves for several different developing times so we can guess how much of the speed increase is due to contrast increase.

I wish I had some tables to show, but as you can see from my latest post, the films were not developed to high contrast. In fact, the contrast on the Tri-X test was lower than recommended even for condenser enlarger. I'd probably have to print it on grade 4 on my diffusion enlarger.

 

[dancqu]

I'm sorry, the figures aren't contrast index. It's
zone VIII density minus zone I density.

I feel fairly confident that increasing phenidone increases shadow
speed. Especially in the case of the Tri-X test I mentioned above,
there was almost a 2-stop increase in speed as compared to
straight PC-TEA.

The use of CI when zone VIII is meant has had me wondering and
Mr. Gainer off on a tangent.

I don't understand Mr. Gainer's questioning your results. After
all PC and TEA are to some extent his babies.

I've two issuses of Darkroom Techniques from the early 80s
which extol the virtues of Perfection XR-1 and it's speed increasing
abilities. Why fight it. At www.unblinkingeye.com they have
a good article on XR-1. Three agents are used but maybe two
will do.

Your ph may be a bit high. You've mentioned perhaps more grain
than will result from a lower ph solution. Dan

 

[sanking]

I've two issuses of Darkroom Techniques from the early 80swhich extol the virtues of Perfection XR-1 and it's speed increasing
abilities. Why fight it. At www.unblinkingeye.com they have
a good article on XR-1. Three agents are used but maybe two
will do.

Can anyone tell me if the two issue of Darkroom Techniques that feature XR-1 provided any evidence of sensitometric testing to support the claims made for speed increasing ability? I have looked at the article at www.unblinkingeye.com but see nothing there about how it was determined that this developer is indeed speed increasing.

When we compare developers for effective printing speed, sharpness and grain it is essential that the comparison film be developed to the same CI in both developers. If not one or more of the features we would like to compare will be different on the two films and the comparison rendered virtually useless.

From my own experience in testing films and developers I have come to the conclusion that true increases of effective film speed of more than 1/4 stop are extremely rare when the comparison films are developed to the same CI. And this has been true even when comparing developers at the extremes, i.e. a developer such as ABC Pyro which is known to be speed decreasing with one of the phenidone based developers reputed to be speed increasing. There is of course plenty of anecdotal literature that claims speed increases of two or three stops but when you look at the testing you find that the methodology is too flawed to support the conclusions rendered.

Sandy King

 

[gainer]

The use of CI when zone VIII is meant has had me wondering and
Mr. Gainer off on a tangent.

I don't understand Mr. Gainer's questioning your results. After
all PC and TEA are to some extent his babies.

I've two issuses of Darkroom Techniques from the early 80s
which extol the virtues of Perfection XR-1 and it's speed increasing
abilities. Why fight it. At www.unblinkingeye.com they have
a good article on XR-1. Three agents are used but maybe two
will do.

Your ph may be a bit high. You've mentioned perhaps more grain
than will result from a lower ph solution. Dan

I'm not fighting it. I just don't believe it. Apparently not enough people believed it to keep it in production. Maybe its shelf life was not long enough. The fact that 96 F was specified for some uses may have contributed to its demise. I would suggest that you might try mixing most of the ingredients of the stock in TEA or glycol. If you do that, you will need only a gram of so for each gram of hydroquinone to get the activity, and you may find the grain to be pretty good. You could add as much sulfite to the working solution as the spirit moves.

If you multiply the amounts of the developing agents by 2.5 and dissolve them in 100 ml of TEA, a dilution of 1:25 will have the same ingredients as the stock listed in Unblinkingeye and pretty close to the specified pH. Diluting 1:50 would be the same as diluting the XR-1 stock 1:1. If anyone wants to try it, I won't accuse you of stealing my idea. Unless, of course, it turns out to be the supreme developer of all time. Try it first without sulfite. Add sulfite a gram at a time to the working solution to see if it helps.

 

[gainer]

P.S.
You might try substituting ascorbic acid for the hydroquinone. It does not need sulfite for superadditivity with either metol or phenidone.

 

[dancqu]

...I have come to the conclusion that true increases of effective
film speed of more than 1/4 stop are extremely rare when the
comparison films are developed to the same CI. Sandy King

Did you take notice of the very large amount of phenidone in
Perfection XR-1? Dr. Gudzinowicz has an explanation of XR-1's
phenominal performance at rec.photo.darkroom. I think you
can find that post by searching there for, perfection xr-1
anneman .

I've a copy of the patent; 4,083,722. There may be room for
A. acid as one of the three agents used. That would make xr-?
a PMC developer. AMP I prefer, A for Ascorbic.

The June 1981 and December 1982 issues of Darkroom Techniques
have very convincing articles. The first is by WEG Thomas and
the second by J. H. Shelton.

I have mentioned Perfection XR-1 because psvensson saw
increased shadow density with increases in phenidone
levels. Dan

 

[sanking]

Did you take notice of the very large amount of phenidone in
Perfection XR-1? Dr. Gudzinowicz has an explanation of XR-1's
phenominal performance at rec.photo.darkroom. I think you
can find that post by searching there for, perfection xr-1
anneman .

Dan

Yes, I did look at the formula and it is indeed quite unusual. However, I am a very skeptical person by nature and my optinion is that getting a *true* speed increase of two or three stops from any develper is simply not possible if we adhere to standard protocol for determining the speed point of fillm, or for that matter if we observe only the protocal of comparing films developed to the same CI. So regardless of what other experts may have theorized, until I see a set of comparision curves made with XR-1 using sensitometric testing based on good methodology I am going to remain totally skeptical about any and all claims for this level of speed increase.

Sandy

 

[dancqu]

Yes, I did look at the formula and it is indeed quite unusual. However, I am a very skeptical person by nature and my optinion is that getting a *true* speed increase of two or three stops from any develper is simply not possible if we adhere to standard protocol for determining the speed point of fillm, or for that matter if we observe only the protocal of comparing films developed to the same CI. So regardless of what other experts may have theorized, until I see a set of comparision curves made with XR-1 using sensitometric testing based on good methodology I am going to remain totally skeptical about any and all claims for this level of speed increase. Sandy

I took a closer look at one of those articles. A test of Tech Pan in
Technidol, FG-7 and XR-1 was made with three rolls of 35mm.
All prints published look a stop underexposed. EIs of 25, 25,
and 100 were used in that order.
EIs of 12.5, 12.5 and 50 I think would be about right
looking at the published photos; all outdoors of the same subject.
At 16 diameters the FG-7 looked horrible.

The other article, by WEG, has really fine photos. Several films
were tested. Increase in speed ran from three to 10 times 'box'
speed. Psvensson uped his Tri-X one stop and he was'nt
even trying. Dan

 

[gainer]

I am leary of anecdotal speed increases. I would rather see the results of tests made on sections of the same subject photographed on the same roll of film. The relative speed means more to me than the absolute speed. My practice is to shoot 1 36 exp. roll of a pictorial subject and one of a step density wedge, each roll at the same f-stop, shutter speed. Prints and plots of density will reveal more than any statement of the sort "I shot it at 200". Different people use meters differently, and rarely have I seen it specified exactly how it was done.

I have used Tri-X at 800 according to my camera, but I would not want to guarantee that any other camera would do the same. Same for light meters. My favorite method used to be to set the meter for 1600 and read dark shadows. Was I actually using ISO 1600? not by a long shot.