Improved version of DS-10 by Ryuji Suzuki?

[albada]

Mark; Both the pH and the buffer capacity of those solutions change. You may also include ionic strength in that change. So, by making one ostensible change, you have actually made 3.
Also, without contrast comparisons, it is hard to judge grain. And, you have to consider sharpness, which may have gone down due to decreasing edge effects. PE

I plotted the curves. Wouldn't they show the effects of those 3 changes on density? Anyway, all curves were quite close (ie, nearly same contrast), so I compared their grain.

But I had not considered sharpness. The test shots of the Stouffer wedge were hand-held, so sharpness-checks must wait for the next roll.

Also, I'm a little surprised that the longer time spent in the sulfite at low pH didn't improve grain. I thought that alone would cause some improvement at low pH. It's odd, it seems that half the things I try surprise me. That tells me how little I understand the development process.

Mark

 

[Alan Johnson]

I'm a little surprised that the longer time spent in the sulfite at low pH didn't improve grain. I thought that alone would cause some improvement at low pH. It's odd, it seems that half the things I try surprise me. That tells me how little I understand the development process.

Mark

Kodak Labs designing Xtol presumeably had the use of a microdensitometer that could measure RMS granularity.
I know this is not the figure they quote but their investment seems to give them an advantage over what can be done without one, for instance measure print graininess.
A difference of 6% in RMS granularity corresponds to just one "just noticeable difference" in graininess.( R.Henry,Controls in Black and White Photography p201).

 

[albada]

Kodak Labs designing Xtol presumeably had the use of a microdensitometer that could measure RMS granularity.
I know this is not the figure they quote but their investment seems to give them an advantage over what can be done without one, for instance measure print graininess.
A difference of 6% in RMS granularity corresponds to just one "just noticeable difference" in graininess.( R.Henry,Controls in Black and White Photography p201).

You're making me wish I had a good 250X-1000X microscope. With that, I could simply take a digital picture of the grain and run it thru some software to score the graininess. That would be a good way of changing a subjective judgement into objective, and would probably give granularity measurements comparable to Kodak's setup.

Mark Overton

 

[Alan Johnson]

How to measure small differences in granularity comes up here from time to time, sometimes it is suggested to make silver gelatin prints and report conclusions.Another method would be to make photomicrographs,I made the attached from T-max 100 using an old inexpensive microscope but have never tried this for comparing granularity.
At a guess small differences might be more visible using a more grainy film like Foma 400 but I don't recall any comment on this either.
A good method used in industry is to copy what the best Americans did which in this case would be Kodak pH 8.2.

 

[Gerald C Koch]

I believe that Kodak for many years submitted prints to a group of people and had them rate the relative grainess of films in this manner. This whole topic is very subjective and even using RMS granularity is subject to criticism.

 

[Photo Engineer]

We evaluated grain and sharpness both, and if color we evaluated color balance and fidelity. I was a participant in these tests from both sides. I took the test and I gave the test. Usually, we had hundreds of prints and hundreds of participants.

PE

 

[albada]

Although I've been posting little, I'm still doing experiments and dialing-in the numbers on a concentrate that gives XTOL-like quality. Speaking of XTOL, the graph below is two identically exposed successive frames on the same strip, developed at the same time in XTOL. These were TMY2 for 6.5 minutes at 20C, with temperature held constant by keeping the tank in a water-bath:

I expected these curves to be nearly identical. Any idea why they diverge so much? Perhaps due to differences in fluid-flow in different parts of the tank?

The shutterspeed should be consistent, as I measured it on both sides of the film-plane with my shutterspeed tester. The OM-1 consistently got 16.6 ms for 1/60th on both sides. So I doubt the differences are due to exposure. Fluid-flow is all I can think of, unless somebody has a better idea.

Anyway, the graph below shows the straighter XTOL curve from above, with my developer (in green). I'd say I need a bit more density, except the curves converge at the right. Odd.


The one-litre formula for the green curve is:

Sodium sulfite ......................... 90 g
Ascorbic acid .......................... 9 g
Sodium metaborate 4 mol ...... 6.2 g
Dimezone S ............................ 0.2 g

Target pH is 8.3 (same as XTOL).
Use same times as XTOL.
​

Grain looks identical to XTOL in my 22x loupes. Except for the sulfite, this formula can be dissolved into 24 ml of propylene glycol, yielding a concentrate that can be used at 1+29 dilution. I'm still tweaking this formula. By the way, I found that Phenidone can be substituted at half the weight of Dimezone S, so the above formula would use 0.1 g of Phenidone.

Mark Overton

 

[albada]

Mark, for what it's worth, in comparison to the various other general purpose solvent developers I've tested, in densitometric tests I've consistently found XTOL (at stock and various dilutions) to show both the most variability roll to roll and even frame to frame, and choppier overall density growth (curve shape). Michael

Michael, this makes me ask, "Then why am I trying to imitate the stuff?" Your posting also made me wonder about the choppiness of my developer, so I plotted the last few frames of the prior test-roll. I was tweaking the formula, so density varies some frame-to-frame. Here are five frames:

My developer has little choppiness; certainly less than what I saw with XTOL. The linear areas are reasonably straight. I don't know why choppiness would differ, unless it's because I'm using ascorbic acid instead of ascorbate, and over 50% more borates than XTOL, and thus I probably have better buffering.

Mark Overton

 

[Sidd]

Here is the formula of Gainer's PC Borax:

Phenidone.....................0.15g
Ascorbic Acid.................6.0g
Borax decahydrate..........19g
Water to.......................1L
pH~9
Develop for D-76 times.1L is said to process 12 rolls film.

I have used this, it works well.
It looks like you are on the way to making a somewhat similar developer but with added sulfite and lower pH to give finer grain.They usually put a little sodium metabisulfite in to make a buffer (Xtol,Mytol).
Hope you reveal your next formula.

@Alan Johnson I have asked you regarding this a few days ago. Thank you, for your answer thirteen years ago. Just saw this post.

 

[john_s]

....... By the way, I found that Phenidone can be substituted at half the weight of Dimezone S, so the above formula would use 0.1 g of Phenidone.

Mark Overton

I know this was from 12 years ago(!) but that comment caught my eye. Over the years there have been numerous estimations of how much Dimezone-S to use instead of Phenidone. Often equimolar is suggested (x1.27), sometimes significantly more, and sometimes different factors depending on whether the developer is full strength (e.g. XTol, Microphen) or highly dilute, like Pyrocat-HD. Does anyone have any test results?

 

[Rudeofus]

I know this was from 12 years ago(!) but that comment caught my eye. Over the years there have been numerous estimations of how much Dimezone-S to use instead of Phenidone. Often equimolar is suggested (x1.27), sometimes significantly more, and sometimes different factors depending on whether the developer is full strength (e.g. XTol, Microphen) or highly dilute, like Pyrocat-HD. Does anyone have any test results?

I don't expect credible test results giving you a precise 1:x ratio. There will be too many influences like pH, choice and quantity of secondary developer, .... it'll end up the same as "carbonate vs. lye substitution".

 

[Alan Johnson]

@Alan Johnson I have asked you regarding this a few days ago. Thank you, for your answer thirteen years ago. Just saw this post.

Sorry but I forgot about using Gainer's formula.
512 Borax is an improved version and the Gainer version was mentioned in the thread:

My PC-512 Borax Developer

When I get some more time I will try to get a better view. I am used to looking at grain like this so it made sense to me. I won't be printing for awhile, but I will see if I can get a shot through the grain focuser on the enlarger. Karl, You don't have to go through that trouble for me...

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