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Kirk Keyes
03-23-2012, 11:11 AM
[QUOTE=albada;1318148]I mu low-pH PC-type developer yields extremely fine grain. Here's an example:
mark
plese tell us more about this developer.

Please tell us more about this VW. :^)

I'm guessing it's a '63 or so.

albada
03-23-2012, 04:32 PM
Please tell us more about this VW. :^)
I'm guessing it's a '63 or so.

I wish that bug were mine. But I have over 100 classic cameras, and I overhaul them myself. Plus I'm learning about developer-chemistry, so the last thing I need is another hobby. The bug belongs to a friend, and that's his daughter standing outside. You're better at estimating years than I am; the closest I could come is "sixties".


plese tell us more about this developer.

Here's the one-litre version of the developer I used. I plan to make something like this into a concentrate, with the sulfite added separately:

Sodium sulfite -------------- 48 g
Ascorbic acid --------------- 7.4 g
Sodium metaborate --------- 4.2 g
Phenidone ------------------ 0.05 g

Target pH is 8.00. For Tmax-400: 13 minutes at 20C. For Tri-X: Around 17 minutes.
However, I think I damaged some of my chemicals with difluoroethane, so the film was underdeveloped, giving thin negatives with very fine grain.

The new chems arrived today, so I'm about to re-test.

Mark Overton

Kirk Keyes
03-27-2012, 10:31 PM
You're better at estimating years than I am; the closest I could come is "sixties".

I own my grandmother's 1966 Beetle (the last year they had a 6 volt battery) and my dad owns a 1956 Beetle (the last year of the small, oval rear window).

albada
03-28-2012, 08:25 PM
I own my grandmother's 1966 Beetle (the last year they had a 6 volt battery) and my dad owns a 1956 Beetle (the last year of the small, oval rear window).

Kirk, here's another shot of this Beetle:
48617

Notice how grainy the dark areas are. The film was underdeveloped due to the problem in the "Why are my developers failing?" thread, and the grain comes from trying to pull detail out of the toe with the scanner. It gets ugly when one reaches far into the toe. This would be difficult to print decently, and this neg probably belongs in the trash.

Anyway, I notice the large rear window, and the older-style curved bumpers. The headlight lenses don't look original to me, and the wheels certainly aren't. I prefer exact restorations of classic cars, not these mixtures.

Mark Overton

Kirk Keyes
03-29-2012, 07:34 PM
Looking at the front door posts and the front turn indicators, I'm guessing it's a '65 or 66. It has to be before 1967 as they could not have covered headlights in 1967.

See my comments on the developer failure thread - I think your film is underexposed and my need a bit more development time.

Don't sweat the wheels - they are 60s period replacement "hot wheels" that were really common. The easiest way to soup up your Bug was to get cool wheels for it. Alloy mags would have been nicer, but, what the heck. You're right that the headlight covers are funky though - too much glass compared to originals. The roof rack is nice though, and if original pretty hard to come by nowadays.

albada
04-02-2012, 01:04 AM
After spending a month dealing with the yellow+thin problem with my ascorbate developers (and XTOL) with TMY2, I'm finally back to working on developers again. From concentrate, I mixed some low contrast developer posted here (http://www.apug.org/forums/viewpost.php?p=1285367).

Rudeofus:
This is the low contrast developer you tried a couple of months ago, and that got you hooked on home-brews.

Now that I have a densitometer, I was able to compare this developer with XTOL, in the following graph:
48825
Most people would find this chart boring, but I'm fascinated by it: This developer will boost shadow-detail without blocking the highlights. In my loupe, highlight-grain is slightly coarser than XTOL, and shadow-grain is much coarser. The shadows look pushed.

Here's what you get when you reduce dev-time some:
48826
Yes, the highlights have lost density as you'd expect, but the shadow-detail is still above XTOL. In fact, shadow-density was almost unaffected by reducing dev-time. I'm thinking this soup would be good for pushing, and outstanding for any high contrast lighting situation.

But why is the contrast lower? Earlier, I posted that I suspected that poor buffering was holding back the highlights. But wouldn't that cause the curve to flatten toward the right? These curves are straight lines, with no sign of shouldering, so I'm thinking my theory of poor buffering is wrong.

Mark Overton

Kirk Keyes
04-02-2012, 02:18 AM
You should really try to get matching Contrast Indices for the two developer/films that you want to compare. You haven't seen the whole story of these developers until you match the slopes.

Give your Locon-1 developer a bit more time until the CI/Gradient/Slope matches the XTOL curve you have.

albada
04-02-2012, 01:57 PM
You should really try to get matching Contrast Indices for the two developer/films that you want to compare. You haven't seen the whole story of these developers until you match the slopes.

That's what should be done for normal general-purpose developers. In this case, I want lower contrast (lower CI), and the unequal CI's makes comparison difficult. The best I could do for grain-comparison was to compare where densities were equal.

The reason I like this developer is that shadow-detail is superior to XTOL even though the CI is lower. One experiment I'm thinking of doing is to give it even less development, reducing the CI even more, to the point where shadow-detail matches XTOL. That should yield a very large dynamic range (ie, very low contrast), which would be useful for situations with extreme contrasts, such as a sun-lit scene combined with a deeply shaded area, or harsh indoor lighting, or a moon-lit night-shot where you want to see detail in the moon.

Mark Overton

Kirk Keyes
04-02-2012, 09:22 PM
Well then develop so that you get a lower, matching CI with XTOL and then compare them...

albada
04-02-2012, 11:20 PM
Well then develop so that you get a lower, matching CI with XTOL and then compare them...

I didn't think of that!

albada
04-16-2012, 12:16 AM
After fighting TMY2 trouble for over a month, I'm finally back trying to formulate developers again.
Today's test was to use no sulfite. But to get finer grain than Gainer's formulas, I kept the pH at 8.0. I tried 100 ml of this 1-litre formula:

Ascorbic acid ...................... 12 g
Sodium metaborate ............ 10.5 g
Dimezone S ........................ 0.20 g

pH = 8.0. Dev'd a strip of TMY2 for 20 minutes at 20C.
The result was a clean-looking negative and purple developer, as you see below:

49551

I suspected that the lack of sulfite let the dyes in the film dissolve, but that purple seems too strong for just 1-1/2 frames. The wash-water only had a very slight magenta tint, so I think most dye was dissolved into the developer.

My densitometer confirms that the neg was thinnish. Also, about one-stop of speed was lost in the shadows.

Questions for the experts:

1. Does sulfite prevent dyes from dissolving into the developer? If so, does that amount of purple look reasonable? The picture matches what I saw.

2. Why does this take so much longer than DS-10 to develop? The pH and Dimezone are the same. Does sulfite remove oxidation-products of the Dimezone? With that not happening, I could see those oxidation-products throttling development.

3. Would using a halide-solvent restore some speed-loss? I've read that sulfite uncovers latent image sites, boosting speed, which obviously isn't happening in this developer.

Mark Overton

Gerald C Koch
04-16-2012, 06:56 PM
Mark

Sulfite plays an important role in the superadditivity of various developing agent combinations including Phenidone / Dimezone and ascorbic acid. Superadditivity is very dependent on sulfite ion concentration. This is especially true for the induction period. Also the solvent action of sulfite exposes additional development sites on the halide crystals. The net effect is to increase development.

albada
04-18-2012, 01:10 AM
Sulfite plays an important role in the superadditivity of various developing agent combinations including Phenidone / Dimezone and ascorbic acid. Superadditivity is very dependent on sulfite ion concentration. This is especially true for the induction period. Also the solvent action of sulfite exposes additional development sites on the halide crystals. The net effect is to increase development.

I remember that sulfite affected superadditivity of something -- hydroquinone perhaps -- but had no idea that it affected P+C. That's good to know and thanks for the posting!

Mark Overton

RidingWaves
04-18-2012, 04:06 PM
So, by altering the amount of Sodium Sulfite you can vary the intensity of the superadditivity between P and C....hmm!

Photo Engineer
04-18-2012, 07:09 PM
It isn't that easy. T&E are needed here.

PE

Gerald C Koch
04-18-2012, 11:29 PM
So, by altering the amount of Sodium Sulfite you can vary the intensity of the superadditivity between P and C....hmm!

I don't know why anyone would want to do what you postulate since superadditivity is a desirable feature of any film developer.

albada
04-19-2012, 01:38 PM
I don't know why anyone would want to do what you postulate since superadditivity is a desirable feature of any film developer.

I was moving toward a concentrate using only organic solvents, which forced me to remove sulfite, and surprise! Much of the superadditivity was lost. Frustrating.
Is there something other than sulfite which can recover the lost superadditivity? If not, I guess I'll boost the pH and quantity of developer and see how it looks.

Mark Overton

Gerald C Koch
04-19-2012, 04:44 PM
Mark,

My comment was about the notion of fine-tuning the amount of superadditivity. Either you want it or you don't. Trying to get something in between would be very difficult as PE mentions.

The problem with glycol or TEA baseed concentrates is the inability of the home experimenter to get sulfite into the mix. Kodak had to use a DEA-sulfur dioixide adduct to do this. This is why I gave up on the idea.

Jerry

RidingWaves
04-19-2012, 08:50 PM
Ah. I see.

Alan Johnson
04-20-2012, 10:16 AM
I was moving toward a concentrate using only organic solvents, which forced me to remove sulfite, and surprise! Much of the superadditivity was lost. Frustrating.
Is there something other than sulfite which can recover the lost superadditivity? If not, I guess I'll boost the pH and quantity of developer and see how it looks.

Mark Overton
I don't know its effect on superadditivity but ammonium thiocyanate is a silver solvent and it dissolves in propylene glycol on gentle heating (I just tried it).All else I know about thiocyanates in film developers is that there is some potassium thiocyanate in Spur HRX-3 developer and IIRC it was noted that Kodak were doing some experimental work at one time.