Who is actually making new formulas? What have you made!?

[Rudeofus]

I'm not chemistry minded enough to understand the diagram, but ascorbate is a very fog prone developer when at a pH high enough that it can work alone. Benzotriazole is the only thing that can prevent the fog that comes with it, starts to become active at pH 11, but only really becomes reasonable at pH 12 or above

Alan's chart shows, how strong an oxidizer or reducer a compound is at different pH values. Positive values mean oxidizer, negative values mean reducer. The lower the shown voltage, the stronger a reducer the compound is. You probably won't be surprised to see, that Metol, HQ and the like become stronger reducers at higher pH.

At any pH sulfite is a stronger reducer than most common development compounds. If a compound becomes too strong a reducer (like dithionite), it will fog film/paper, i.e. develop unexposed parts. Sulfite is a very special exception, and it has been the subject of advanced research, why sulfites do not reduce Silver ions. Any developer reaching its reduction potential would fog film/paper immediately.

Which brings me to Alan's statement about the reduction potential of ascorbates. Since ascorbates do not enjoy the same exceptional properties of sulfites, they would fog film immediately at an oxidation potential below -0.4V. Obviously they don't. From the evidence at hand we can conclude, that ascorbates are in a similar league as HQ and the likes, and that its oxidation potential will not drop below the one of sulfite.

 

[Alan Johnson]

Alan's chart shows, how strong an oxidizer or reducer a compound is at different pH values. Positive values mean oxidizer, negative values mean reducer. The lower the shown voltage, the stronger a reducer the compound is. You probably won't be surprised to see, that Metol, HQ and the like become stronger reducers at higher pH.

At any pH sulfite is a stronger reducer than most common development compounds. If a compound becomes too strong a reducer (like dithionite), it will fog film/paper, i.e. develop unexposed parts. Sulfite is a very special exception, and it has been the subject of advanced research, why sulfites do not reduce Silver ions. Any developer reaching its reduction potential would fog film/paper immediately.

Which brings me to Alan's statement about the reduction potential of ascorbates. Since ascorbates do not enjoy the same exceptional properties of sulfites, they would fog film immediately at an oxidation potential below -0.4V. Obviously they don't. From the evidence at hand we can conclude, that ascorbates are in a similar league as HQ and the likes, and that its oxidation potential will not drop below the one of sulfite.

Yup, Rudi seems to be right. Here is a diagram from 2017 puts ascorbate above sulfite and below the others.
https://www.researchgate.net/figure...c-acid-in-water-Solid-line-The_fig1_316518011

 

[grainyvision]

Alan's chart shows, how strong an oxidizer or reducer a compound is at different pH values. Positive values mean oxidizer, negative values mean reducer. The lower the shown voltage, the stronger a reducer the compound is. You probably won't be surprised to see, that Metol, HQ and the like become stronger reducers at higher pH.

At any pH sulfite is a stronger reducer than most common development compounds. If a compound becomes too strong a reducer (like dithionite), it will fog film/paper, i.e. develop unexposed parts. Sulfite is a very special exception, and it has been the subject of advanced research, why sulfites do not reduce Silver ions. Any developer reaching its reduction potential would fog film/paper immediately.

Which brings me to Alan's statement about the reduction potential of ascorbates. Since ascorbates do not enjoy the same exceptional properties of sulfites, they would fog film immediately at an oxidation potential below -0.4V. Obviously they don't. From the evidence at hand we can conclude, that ascorbates are in a similar league as HQ and the likes, and that its oxidation potential will not drop below the one of sulfite.

That's really fascinating. Is there any reading you can recommend to explain the inaction of sulfite on silver halide? I always assumed silver halide was less reductive than HQ etc, rather than significantly more reductive

 

[Tom Kershaw]

My Ascorbic Acid arrived and I mixed up and ran a few prints this evening with reasonably good results - just some old ILFORD MGIV RC GLOSS paper.

formula based on 'E-72':

Water (distilled)	750ml
Phenidone	0.3g (from percent solution)
Sodium Sulphite (Anhy)	45g
Ascorbic Acid	20g
Sodium Carbonate (Anhy)	77g
Potassium Bromide	2g
Water (distilled) to make	1000ml

A couple of lessons from this first attempt:

• used a dilution of 1+2 (1000ml stock + 2000ml tap water) for my print solution. This may be slightly too weak - I will probably try 1+1 next.
• plan to make another phenidone based mix alongside a version with 3g Metol to look at any potential colour differences. My experience in the past is that Metol can produce cooler / neutral tones.

 

[Rudeofus]

If E-72 1+2 was too weak, then maybe the ascorbate decayed too fast. The stock formula you posted looks plenty concentrated enough to handle 1+2. Take a look at Ryuji Suzuki's print developer formulas, these should last a lot longer.

 

[Tom Kershaw]

If E-72 1+2 was too weak, then maybe the ascorbate decayed too fast. The stock formula you posted looks plenty concentrated enough to handle 1+2. Take a look at Ryuji Suzuki's print developer formulas, these should last a lot longer.

I processed an additional four prints through the same working solution this evening and performance was absolutely comparable so I may have been over-hasty in my negatives comments. Induction time with this 'E-72' developer is fairly long but 2 minutes produces excellent results.

 

[Tom Kershaw]

I made another batch of the paper developer on the 24th and found that it still worked perfectly today, with very good D-max.

 

[esearing]

Pyrocat M (Metol) for second pass paper developer after fixing and bleaching. Yields warm tones not quite brown but not olive eitheron ilford fiber papers. Dilute 10mlA +8mlB +1LWater. Part B is the standard Pyrocat HD part B with potassium carbonate. I use either a Pot-Ferri bleach or Bromoil Dichromate bleach. The redevelopment is slow at this dilution and used oneshot for 160sq inches of paper.
Jay DeFehr's Obsidian Aqua does the same but stains the paper more in my initial experiments. Might be interesting with the new RC papers from Ilford.

 

[grainyvision]

Today I saw a post asking if a sulfite-free paper developer existed due to an allergy to sulfite. To my knowledge I've not seen one, so I decided to whip one up. Post I made in another group about it:

Out of curiosity from XXXX's post about a sulfite free paper developer, I decided to quickly whip one up from phenidone and vitamin C. Actually works really well, though I expect shelf life to be awful. Contrast can be kinda weird, recommend increasing contrast by 1/2 grade on most papers, and warmtone papers will behave very slow (exposure-wise), but otherwise it just seems to work
To 1L of room temp water, add

• 20g ascorbic acid (vitamin C)
• 0.35g phenidone
• 23.2g sodium carbonate, anhydrous (note: solution will fizz up! add slowly)
• 1.5ml of 1% benzotriazole (can be dissolved easily in 30:70 mixture of isopropyl alcohol to water) -- note this is potentially optional. I had no problems with RC papers but introduced it when trying out retrobrom paper which fogs easily anyway
• Stir until everything is dissolved. Can be done very quickly with a magnetic stirrer, with hand stirring takes about 5 minutes
• Solution will appear very slightly straw yellow and will appear cloudy

Usage: 1m for most RC papers, 2m for most FB papers
Note! Including propylene glycol in this formula (such as phenidone stock solutions) have been observed in previous similar formulations to increase fog levels. I recommend avoiding it, it doesn't really take that long to mix up anyway.
Appearance: slightly warm to neutral tones, can be cold as well. Tends to be extremely variable with the material. Very open shadows, recommended to increase grade by 1/2 to get deeper blacks with more contrast
Tested papers: Fomatone FB, Fomatone RC, Ilford MGV RC, Ilford Cooltone FB, Ilford Warmtone FB, Foma retrobrom FB(not recommended, weak contrast and black depth with tendency to fog easily)

 

[relistan]

Note! Including propylene glycol in this formula (such as phenidone stock solutions) have been observed in previous similar formulations to increase fog levels. I recommend avoiding it, it doesn't really take that long to mix up anyway.
Appearance: slightly warm to neutral tones, can be cold as well. Tends to be extremely variable with the material. Very open shadows, recommended to increase grade by 1/2 to get deeper blacks with more contrast
Tested papers: Fomatone FB, Fomatone RC, Ilford MGV RC, Ilford Cooltone FB, Ilford Warmtone FB, Foma retrobrom FB(not recommended, weak contrast and black depth with tendency to fog easily)

This is an interesting paper developer, thanks! As a semi-regular user of PC-Glycol, I wonder about the fog and propylene glycol. I have been using the same batch since 2017 so I haven't mixed it in a long time. I did notice from the beginning that I have to add some potassium bromide to control the fog level. But I previously read that overheating the phenidone when mixing will also do that. Is this a feature of propylene glycol or is it something to do with heat and propylene glycol or heat and phenidone?

 

[Tom Kershaw]

I made another batch of the paper developer on the 24th and found that it still worked perfectly today, with very good D-max.

This batch of developer was still working this evening but showed signs of exhaustion - worked fine last Friday so suggest 2 weeks is realistic for keeping time. Possibly 7-10 days for maximum performance.

 

[bluechromis]

Re: ascorbate paper developers: I am curious if anyone has tried the recipe in the Photrio resource section for an ascorbate paper developer along the lines of Ansco 130.
https://www.photrio.com/forum/resources/pc130-variation-on-ansco-130.147/

 

[bluechromis]

This is an interesting paper developer, thanks! As a semi-regular user of PC-Glycol, I wonder about the fog and propylene glycol. I have been using the same batch since 2017 so I haven't mixed it in a long time. I did notice from the beginning that I have to add some potassium bromide to control the fog level. But I previously read that overheating the phenidone when mixing will also do that. Is this a feature of propylene glycol or is it something to do with heat and propylene glycol or heat and phenidone?

Re: glycol & fog with PC-Glycol, I would have thought that the alkalinity of the developer might have been more a culprit with fog. I am using an ascorbate/glycol film developer called PG110B that produces little or no fog.

 

[mshchem]

When I was younger I made developers with glycin. I settled on Ilford Bromophen, it's a fabulous stable developer. I use gold toner (Kodak Blue toner) blue black tones, Selenium too. Magic happens with toners and papers with moderate amounts of silver chloride. Warmtone and Azo like contact papers, Lupex, Fomalux etc.

 

[Tom Kershaw]

On Sunday I processed a roll of TMX 100 in DS-2 developer - dilution 1+4 from the "concentrate" - and results were as fresh. Developer concentrate mixed on January 26th - stored in full 250ml HDPE bottle.