D-23 dilution, replenishment.

Lachlan Young · Feb 13, 2022

Donald Qualls said:
When I was using replenished D-23, I thought the grain was mushy in my scans at 1200 ppi.

Unless these scans were done on high end equipment, the only thing you will have been testing is the MTF (or lack thereof) of the scanner. The classic D-76/ D-23 (et seq) developers from Kodak are perfectly capable of delivering better than good sharpness - but most consumer grade scanners are themselves fundamentally not sharp enough (for various optical/ mechanical reasons) to even hint at reproducing most of the film/ developer combination's sharpness characteristics.

Donald Qualls · Feb 14, 2022

Lachlan Young said:
Unless these scans were done on high end equipment, the only thing you will have been testing is the MTF (or lack thereof) of the scanner.

Perhaps that's why negatives processed in Parodinal always showed crisper, cleaner looking grain than those from D-23 on that same scanner, then.

I understand what you're saying, though -- if I can't resolve the actual silver grains (which AFAIK no scanner can do, it takes an electron microscope) there will be some level of sampling artifacts in any scan that seems to show the grain.

OTOH, I now have a scanner with about 4x the optical resolution and better focus than the one I had then; perhaps I should mix up a fresh batch of D-23 and see what I can get. Conveniently, I just loaded up several cassettes each with .EDU Ultra 400, Kentmere Pan 100, and ORWO DN21 over the weekend...

markbau · Feb 14, 2022

MattKing said:
Replenished developer is re-used continuously, so the developer you are going to use (plus the replenisher you are going to add) is sitting there, at room temperature, always ready to go without any temperature control.
Other approaches require either temperature control while diluting stock or concentrate, or variation in development time as more and more films are developed in the same volume of stock, or the relatively un-economical one-shot use of pre-mixed stock developer.
The closest parallel to the work flow is probably some of the re-usable two bath options like Diafine.

I don't mean to be pedantic but I really don't see how you can claim the fact that your developer and replenisher are sitting there at room temp to be an advantage. Whatever stock developer I'm using is mixed with water and brought up to 20C. If you've been doing this for a while you know that if the stock is at 18 and tap water is at 20 turn the temp up to 22 and once mixed you'll have 20. (I have an Intellifaucet) Even without this technology, getting a developer to the temp you want is no big deal.
I was hoping you would claim replenished developer has increased sharpness/acutence or some other quality but having them at room temp is no big deal.

markbau · Feb 14, 2022

Another thing about D-23 is the development times.
An old Kodak publication says to develop undiluted for 18 minutes at 25C
Cookbook/Anchell says to develop for 12 minutes at 20C

!8 minutes at 25C seems absurd, Anchell's times, which I have used, seems a bit long so I'm wondering what others have used for D-23?

Anchell doesn't specify which films his times are for, is it a generic time for all films?

tokam · Feb 14, 2022

markbau said:
Another thing about D-23 is the development times.
An old Kodak publication says to develop undiluted for 18 minutes at 25C
Cookbook/Anchell says to develop for 12 minutes at 20C

!8 minutes at 25C seems absurd, Anchell's times, which I have used, seems a bit long so I'm wondering what others have used for D-23?

Anchell doesn't specify which films his times are for, is it a generic time for all films?

Check John Finch's , (Pictorial Planet), Youtube channel. He does a lot of work with D23 including replenishment and he gives starting times for using this developer with certain films. You may have to extrapolate for other films and, (horror of horrors), actually have to experiment a bit.

Donald Qualls · Feb 14, 2022

That figure of 18 minutes at 25C is probably for pre-1960 films, which would have wanted 17 minutes in D-76 stock (a much more active developer than D-23).

For modern films, I've used the figures on the Massive Dev Chart, or film data sheets when D-23 was listed, and I had good results.

MattKing · Feb 14, 2022

markbau said:
(I have an Intellifaucet)

This, of course, means that you have little need for the inherent advantage of being able to use developer at room temperature.
Like many (most?) here who work with temporary darkrooms, or darkrooms without aids for temperature control, I need to manually adjust a household faucet to set water temperature, and I need to monitor those settings laboriously and relatively constantly in order to maintain temperature at a set target amount (our building shares a single hot water source among many, and the hot water temperature does vary regularly).
I heartily recommend the Intellifaucet and other similar equipment - to those who have a darkroom space to put it in. It adds a level of convenience that truly simplifies life. The rest of us have to find other approaches.

markbau · Feb 14, 2022

MattKing said:
This, of course, means that you have little need for the inherent advantage of being able to use developer at room temperature.
Like many (most?) here who work with temporary darkrooms, or darkrooms without aids for temperature control, I need to manually adjust a household faucet to set water temperature, and I need to monitor those settings laboriously and relatively constantly in order to maintain temperature at a set target amount (our building shares a single hot water source among many, and the hot water temperature does vary regularly).
I heartily recommend the Intellifaucet and other similar equipment - to those who have a darkroom space to put it in. It adds a level of convenience that truly simplifies life. The rest of us have to find other approaches.

Have you ever noticed any difference in image quality between replenished and unrereplenished?

Lachlan Young · Feb 14, 2022

Donald Qualls said:
Perhaps that's why negatives processed in Parodinal always showed crisper, cleaner looking grain than those from D-23 on that same scanner, then.

What I've seen (both darkroom & scanning) largely matches the microdensitometry findings of Richard Henry - that solvent D-76 type developers (and the like) outperform Rodinal in all meaningful visible metrics apart from visible granularity - where Rodinal type developers produce noticeably greater (but not sharper) granularity. Cutting a long story into hopefully a very short form, I wonder if it's because p-Aminophenol might not produce as strong exhaustion effects as Metol (only when Metol is used as the sole developing agent) or inhibition effects like the Phenidones (works both on own & with varying levels of HQ/ other semiquinone sources) and that the Rodinal formulation is not solvent enough to release development inhibition agents (I and Br) from the emulsion(s). Probably not a question answerable outside of a manufacturer's R&D lab.

MattKing · Feb 14, 2022

markbau said:
Have you ever noticed any difference in image quality between replenished and unrereplenished?

Yes, but it is a difference in qualities, not a difference in quality.
And those differences are subtle.
The mid-tones look really nice in the replenished version of X-Tol, and I always pay most of my attention there.
The lower activity of the replenished version vs. fresh stock (without the dilution of the sulfite levels that diluted versions offer) looks different, and is to my taste.

D-23 dilution, replenishment.

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