Dektol vs D72 (My Observations)

[Donald Qualls]

I used some D72 the other day, part used. On the bottle I see it was mixed a year ago. I was surprised to to see that it came out crystal clear but I do fill partial bottles with gas.

Yep, that's it. Oxidation products of p-aminophenol and its derivatives are pretty strong dyes; doesn't take enough of them to affect activity to make the solution turn brown like strong tea. Avoid oxidizing the metol or p-aminophenol in a developer, and it'll stay clear(ish).

 

[Ian Grant]

IIRC Kodak stated plainly that Dektol was in actual fact the commercially packaged version of D72. As already stated by another member above, there are subtle differences between the two which are necessitated by the single package but the differences do not change the essential working character of the developer. The same is true for D76. In both cases, the published formula is the basis for the commercially packaged product.

Yes Dektol and D72 were essentially the same developer, there are two pblished version, one converted to Metric with decimal places and a simpler rounded off version. Where the commecial version differed was the addition of Sodium Metabisulpte in Part A to preserve the Metol & Hydroqinone to compensate there is a very small increase in the Carbonate in Part B,Ilford do this with some drypackaged developers as well.

I should probably give that a try. My hesitancy is that I don't trust the concentrate not to go bad. I used a liquid paper developer (I think it was from Ilford) in the 90s and the print tone became warmer the more I used it. I vowed never to use that developer again and that vow morphed into "I will never use any liquid paper developer again". I can't even remember what the stuff was called. In any case, I do like the utility of a liquid concentrate.

Ilfordc introduced Multigrade deveoper to prevent te shift towards warmer tones with use. Graded Ilfospeed introduded in the 1970's was eveloper incorprated, I used to process it in an Ilfoprint roller processor with a home made activator (with no developing agents). this didn't shift tone in used developer. The fourth generation of Multigrade which was the first RC version unlike Ilfospeed did shift slightly warmer with bromide build up and quite a throughput. After complaints about shifts in warmth whiche were more obvious at som e contrast grades Ilford introduced Multigrade developer.

It's worth pointing our that an MQ developer collapses with the Bromide build up, whereas a PQ developer can tolerate the Bromde and continue far longer, so gas a far greater capacity. I've never used Dektol because it wasn't available in the UK until more recent years, instead Kodak Ltd used to make and sell D163 here as a Universal Film & Print developer. When I switched from D163 to Ilford PQ Universal I noticed a marked increase in capacity.

Ian

 

[Dave Krueger]

PE died last year. RIP
https://www.photrio.com/forum/threa...rey-aka-pe-photo-engineer-feb-15-2020.173245/
https://www.photrio.com/forum/threa...rey-aka-pe-photo-engineer-feb-15-2020.173245/

Thanks for the link. I suspected that might be the case. I always appreciated it when he took time to respond to one of my questions. He always supplied reliable answers and respected others. Sadly, that kind of industry expertise is going to become ever more rare.

 

[Dave Krueger]

Same here - Dektol from the very beginning. Been down many rabbit holes, tried all the magic concoctions, always ended up back with Dektol.

The “much greater capacity” and “better keeping properties” slogans are indeed puzzling, unless it all comes down simply to a sequestering agent, with very loosely stretched advertising. You never know what kind of barely legal ridiculous stuff the ad men and accountants came up with that probably made the scientists’ eyes roll. Just recently someone posted an old Edwal FG7 ad here - “...doubles and triples film speed...”. Lol.

Marketing hype certainly tends to accompany "new" product introductions.

 

[Dave Krueger]

Yep, that's it. Oxidation products of p-aminophenol and its derivatives are pretty strong dyes; doesn't take enough of them to affect activity to make the solution turn brown like strong tea. Avoid oxidizing the metol or p-aminophenol in a developer, and it'll stay clear(ish).

I was thinking about this yesterday. Oxidation is likely to be worst when the chemical is in the tray with a huge surface area exposed to open air, not while it's sitting idle in a sealed container. I am always surprised by how clear working strength paper developer remains just sitting on the shelf. But, one of the nice things about mixing your own is being able to mix up just what you need.

 

[Dave Krueger]

Yes Dektol and D72 were essentially the same developer, there are two pblished version, one converted to Metric with decimal places and a simpler rounded off version. Where the commecial version differed was the addition of Sodium Metabisulpte in Part A to preserve the Metol & Hydroqinone to compensate there is a very small increase in the Carbonate in Part B,Ilford do this with some drypackaged developers as well.



Ilfordc introduced Multigrade deveoper to prevent te shift towards warmer tones with use. Graded Ilfospeed introduded in the 1970's was eveloper incorprated, I used to process it in an Ilfoprint roller processor with a home made activator (with no developing agents). this didn't shift tone in used developer. The fourth generation of Multigrade which was the first RC version unlike Ilfospeed did shift slightly warmer with bromide build up and quite a throughput. After complaints about shifts in warmth whiche were more obvious at som e contrast grades Ilford introduced Multigrade developer.

It's worth pointing our that an MQ developer collapses with the Bromide build up, whereas a PQ developer can tolerate the Bromde and continue far longer, so gas a far greater capacity. I've never used Dektol because it wasn't available in the UK until more recent years, instead Kodak Ltd used to make and sell D163 here as a Universal Film & Print developer. When I switched from D163 to Ilford PQ Universal I noticed a marked increase in capacity.

Ian

Thanks for the thorough explanation. I didn't know P-Q had greater capacity than M-Q. I think I probably discard paper developer after is becomes annoyingly discolored without ever exhausting it. The case where I noticed the increased warmth was when I was doing a huge rush order of prints that had to go out in a press release the next day. One of the rare times I exhausted fresh developer in a single session. I wish I could remember for certain what developer it was.

 

[Dave Krueger]

Same here - Dektol from the very beginning. Been down many rabbit holes, tried all the magic concoctions, always ended up back with Dektol.

From what I've read, a lot of people have tried a lot of different developers looking for something better (higher Dmax, colder tones, etc) than Dektol and not had much luck, so I find it pretty easy to talk myself out of trying new paper developers. Thorough testing can be very time/labor intensive. The older I get, the more I realize how precious time is.

 

[Donald Qualls]

I was thinking about this yesterday. Oxidation is likely to be worst when the chemical is in the tray with a huge surface area exposed to open air, not while it's sitting idle in a sealed container. I am always surprised by how clear working strength paper developer remains just sitting on the shelf. But, one of the nice things about mixing your own is being able to mix up just what you need.

On the other hand, if you're like most non-professional photographers, the developer spends hundreds of times as much time in the storage bottle compared to in the trays -- and most dilute the developer and then discard it after a printing session, so the little darkening that happens in a few hours doesn't get noticed.

 

[Doremus Scudder]

My observations.

I've used Dektol, D-72, Zone VI developer (which was, I believe ID-62, but some say it's just D-72), Bromophen, ID-62 and Liquidol plus a few glycin developers, etc. that are irrelevant here.

I mix mostly from scratch what I need for a session, usually 2-4 liters of working solution, these days of ID-62 or D-72. I find both of these last for two to three darkroom sessions, a session being 4-6 hours or more of printing. The developer is stored in bottles between sessions. I always discard the developer after the third session even if it seems to be working fine still, so I don't really know how much longer it would have lived. I'm sure there's a bit of activity loss over this time, but when I mix up fresh developer in the middle of a print run, I see only a very slight change from old developer to fresh, so the developer is still active enough for printing with appropriate exposure/development time tweaks. I have a rather low throughput, so I don't exhaust the developer due to that; it's always time/oxidation that would be my concern.

At any rate. I find that both D-72 and ID-62 stay clear (i.e., not turning brown) through two sessions. By the end of the third session, they are light honey-colored. They never get to the "strong tea" or "coffee" stages before I discard them.

Liquidol, on the other hand, turns dark in one session, but continues working still. I have had papers (Adox MC-110 stained by Liquidol, so I have stopped using it.)

Unlike Dave, I have seen no real difference in the aging of D-72 and Dektol. There may be some difference, but not significant enough for me to notice.

Both D-72 and ID-62 give nice, dark blacks. To my eye, they are both a bit more active then Liquidol. Like Michael, I don't think the quest for D-max is what it's cracked up to be.

My personal favorite these days is ID-62, but with a smidge more BTA than the formula calls for and a bit less bromide. Seems to give me better whites somehow, but I don't know how. Tone change, if any, is small.

Bottom line, I find storage characteristics and capacity between scratch-mixed and store-bought developers to be very similar, comparing D-72 to Dektol and ID-62 to Bromophen.

It seems to me the the cost of mixing one's own print developer, especially if one uses D-72, is so much less expensive than buying pre-packaged developers (especially if one has to have them shipped) that using them to a bit less capacity (even if that is the case) would still be more economical.

@Dave,
As I mentioned above, I re-use working solution developer for up to three sessions, maybe somewhat similar to what you do, but to a lesser extent. However, when mixing fresh developer when I know I'm going to be printing for many days, I'll mix up the stock solution; enough for two-batches of working solution. I'll use the first batch for three sessions, then start fresh with working solution mixed from the rest of the stock solution and use that for another three sessions. At that point, I'll mix up another batch of stock if I'm still going to be printing for six more sessions. In other words, I only have to mix developer from scratch every six sessions. The stock keeps for months in a full, tightly-capped bottle if I end up not needing to use it. Maybe something similar would work for you? I imagine storing your working solution for a long time is not as good for longevity.

Best,

Doremus

 

[Dave Krueger]

On the other hand, if you're like most non-professional photographers, the developer spends hundreds of times as much time in the storage bottle compared to in the trays -- and most dilute the developer and then discard it after a printing session, so the little darkening that happens in a few hours doesn't get noticed.

I reuse working strength developer for multiple sessions. You are correct that it sits in the tray for a much smaller time than it sits in the container, but there is limited air in the container, whereas there is an infinite amount of fresh oxygen available as it sits in the tray. On the other hand, I agree with your point that I would probably never notice the discoloration if I disposed of developer at the end of each session.

 

[Dave Krueger]

Dmax is a non-starter. Dektol produces as much dmax as any other developer. Nobody can see the difference between dmax values anyway. For cold tones, these are easily obtained simply by adding a compound such as PMT to Dektol (or other developers). Straight out of the box, the only formulas which actually give colder tones than Dektol etc. on contemporary papers are Moersch SE3 and SE6. For warmer tones there are more options and a few of the old formulas seem to work to some extent.

If you want to explore attributes such as longer life and higher capacity, you might like Liquidol. If you're not already familiar with it, it was PE's invention intended to essentially duplicate the working characteristics of Dektol but with (apparently) significantly higher throughput capacity, shelf life and tray life. Just a thought.

I'm fine with the prints I get from D72 (although colder would be better) and am probably more under the influence of inertia than any sense of exploration.

I have never used any Moersch products, but have been intrigued by them. Can they produce cold (blue black) tones on Ilford MGIV and Cooltone papers? How about on RC version of those papers? I don't use warm tone papers because I prefer a bright white (not cream colored) paper base.

 

[Dave Krueger]

My observations.

I've used Dektol, D-72, Zone VI developer (which was, I believe ID-62, but some say it's just D-72), Bromophen, ID-62 and Liquidol plus a few glycin developers, etc. that are irrelevant here.

I mix mostly from scratch what I need for a session, usually 2-4 liters of working solution, these days of ID-62 or D-72. I find both of these last for two to three darkroom sessions, a session being 4-6 hours or more of printing. The developer is stored in bottles between sessions. I always discard the developer after the third session even if it seems to be working fine still, so I don't really know how much longer it would have lived. I'm sure there's a bit of activity loss over this time, but when I mix up fresh developer in the middle of a print run, I see only a very slight change from old developer to fresh, so the developer is still active enough for printing with appropriate exposure/development time tweaks. I have a rather low throughput, so I don't exhaust the developer due to that; it's always time/oxidation that would be my concern.

At any rate. I find that both D-72 and ID-62 stay clear (i.e., not turning brown) through two sessions. By the end of the third session, they are light honey-colored. They never get to the "strong tea" or "coffee" stages before I discard them.

Liquidol, on the other hand, turns dark in one session, but continues working still. I have had papers (Adox MC-110 stained by Liquidol, so I have stopped using it.)

Unlike Dave, I have seen no real difference in the aging of D-72 and Dektol. There may be some difference, but not significant enough for me to notice.

Both D-72 and ID-62 give nice, dark blacks. To my eye, they are both a bit more active then Liquidol. Like Michael, I don't think the quest for D-max is what it's cracked up to be.

My personal favorite these days is ID-62, but with a smidge more BTA than the formula calls for and a bit less bromide. Seems to give me better whites somehow, but I don't know how. Tone change, if any, is small.

Bottom line, I find storage characteristics and capacity between scratch-mixed and store-bought developers to be very similar, comparing D-72 to Dektol and ID-62 to Bromophen.

It seems to me the the cost of mixing one's own print developer, especially if one uses D-72, is so much less expensive than buying pre-packaged developers (especially if one has to have them shipped) that using them to a bit less capacity (even if that is the case) would still be more economical.

@Dave,
As I mentioned above, I re-use working solution developer for up to three sessions, maybe somewhat similar to what you do, but to a lesser extent. However, when mixing fresh developer when I know I'm going to be printing for many days, I'll mix up the stock solution; enough for two-batches of working solution. I'll use the first batch for three sessions, then start fresh with working solution mixed from the rest of the stock solution and use that for another three sessions. At that point, I'll mix up another batch of stock if I'm still going to be printing for six more sessions. In other words, I only have to mix developer from scratch every six sessions. The stock keeps for months in a full, tightly-capped bottle if I end up not needing to use it. Maybe something similar would work for you? I imagine storing your working solution for a long time is not as good for longevity.

Best,

Doremus

Thanks for the ideas. I really don't need to be that frugal with darkroom chemistry anymore, but I have developed habits over the years (and pinching pennies is one of those habits). I could certainly use my developer for fewer sessions and avoid the discoloration, but I just don't feel particularly motivated to change because the prints come out fine. This thread is making me conscious of how resistant I have become to venturing outside my comfort zone.

 

[Dave Krueger]

I didn't test the Moersch products on RC papers, but I imagine they would work similarly. For really "cold" blue-black tones yes I would say SE6. It really works. Alternatively, Moersch also sells an additive called Finisher Blue which you can add to developers to get similar effects to SE6. You can easily vary the amount of "cooling". This would likely be more cost-effective since the Moersch chemicals are not the cheapest around. The primary active compound in Finisher Blue is PMT (Phenylmercaptotetrazole) as I mentioned in an earlier post.

Thanks, Michael. I added SE6 and Finisher Blue to my Freestyle wish list to include with my next order.

 

[Nicholas Lindan]

One change in Dektol powder is some magic done to allow the Metol to dissolve even though it is added at the same time as the Sulfite.

At university I was taught to add a 1/2 teaspoon of P. Bromide and 1/2 tablespoon of S. Carbonate per liter of working Dektol (about triple the Bromide and double the Carbonate). In side by side comparisons the addition produced a warmer tone print that looked a bit more 'brilliant' (a terrible term, I know). I sometimes still do the addition when I feel like reliving my youth...

When doing the sensitometry for the Darkroom Automation system I had to mix up fresh D-72 and toss it after two hours in order to get repeatable results. Developer that was poured back in the bottle after 15 minutes of use and then used the next day also produced different results. The difference wasn't visually significant. It is possible that 'seasoning' the D-72 would result in a stable developer - commercial photofinishers I'm sure had some system of replenishment for web processing of B&W prints.

 

[Doremus Scudder]

One change in Dektol powder is some magic done to allow the Metol to dissolve even though it is added at the same time as the Sulfite.

At university I was taught to add a 1/2 teaspoon of P. Bromide and 1/2 tablespoon of S. Carbonate per liter of working Dektol (about triple the Bromide and double the Carbonate). In side by side comparisons the addition produced a warmer tone print that looked a bit more 'brilliant' (a terrible term, I know). I sometimes still do the addition when I feel like reliving my youth...

When doing the sensitometry for the Darkroom Automation system I had to mix up fresh D-72 and toss it after two hours in order to get repeatable results. Developer that was poured back in the bottle after 15 minutes of use and then used the next day also produced different results. The difference wasn't visually significant. It is possible that 'seasoning' the D-72 would result in a stable developer - commercial photofinishers I'm sure had some system of replenishment for web processing of B&W prints.

Nicholas,

Nice to see you posting again!

I learned the same Carbonate/Bromide trick you did and used it a lot when printing on graded papers. I still keep stock solutions of carbonate, bromide and benzotriazole on hand as print developer additives. A bit of carbonate to boost activity, some benzotriazole to clear the whites and cool image tone or bromide to clean up the whites and warm the tone a bit. With VC papers I don't use the technique as much, but still find it useful at times.

You make a good point about developer changing activity even though it is not exhausted. I'm keenly aware that prints made on the last session of a two- or three-session batch of developer, although fine, likely would need less exposure (and maybe a bit less contrast) if they were made with fresh developer. I note the developer age in my printing record so I'm aware of this when printing the same image later.

Best,

Doremus

 

[Dave Krueger]

One change in Dektol powder is some magic done to allow the Metol to dissolve even though it is added at the same time as the Sulfite.

At university I was taught to add a 1/2 teaspoon of P. Bromide and 1/2 tablespoon of S. Carbonate per liter of working Dektol (about triple the Bromide and double the Carbonate). In side by side comparisons the addition produced a warmer tone print that looked a bit more 'brilliant' (a terrible term, I know). I sometimes still do the addition when I feel like reliving my youth...

When doing the sensitometry for the Darkroom Automation system I had to mix up fresh D-72 and toss it after two hours in order to get repeatable results. Developer that was poured back in the bottle after 15 minutes of use and then used the next day also produced different results. The difference wasn't visually significant. It is possible that 'seasoning' the D-72 would result in a stable developer - commercial photofinishers I'm sure had some system of replenishment for web processing of B&W prints.

That's interesting that you can detect differences in developer after such a short period in the tray, I know developer exhaustion is a variable from "Way Beyond Monochrome". Personally, I only need enough consistency for my enlarging meter to do a reasonably good job and for the Dmax to not noticeably degrade. AT a dilution of 1+1, I don't think I'm getting close to exhaustion, even with the discoloration. Even for routine RC printing of a roll of film, I make at least one test strip for every print and do multiple prints if fine tuning is required. If something is different (developer, paper batch, paper age, filter fading, temperature, line voltage, enlarger bulb brightness, etc), I am going to adjust for it in real time. Since I'm retired and make prints only for myself, I am not on a clock and don't make that many prints. Also, I'm no Ansel Adams when it comes to minutely adjusting tonal rendition to match my previsualization. I'm more like, "Hey, this picture came out better than I thought it would!"

 

[albada]

PS: Nice to see a post by you, Nicholas.

Same here!

And thank you for the enlarger meter I recently purchased from your Darkroom Automation business. It works well, and is invaluable!

Mark Overton

 

[maxpina]

I resume this discussion because today I used for the first time for the development of my prints the D72 that I prepared according to the classic recipe found on the forum and then used diluted 1: 2, compared to the dektol that I normally used in the same dilution. of longer appearance and with much more violent blacks, I use Ilford Multigrade RC New paper, does any of you have experience in this regard?
Thanks

 

[Donald Qualls]

D-72 mixed from formula lacks a couple undocumented ingredients that are in commercial Dektol -- mainly in the line of buffering and water conditioning. It's very possible that changes in the water you used to mix or dilute could have changed the pH of the final developer. Kodak might also have altered the Dektol formula a little in the, what, 85 years? since D-72 was published -- changed the proportion of metol to hydroquinone, for instance, or the buffered pH. Or it might just be that your ingredients were fresher than the Dektol you compared against.

 

[maxpina]

D-72 miscelato dalla formula manca di un paio di ingredienti non documentati che si trovano nel Dektol commerciale, principalmente nella linea di tamponamento e condizionamento dell'acqua. È molto probabile che i cambiamenti nell'acqua che hai usato per mescolare o diluire possano aver modificato il pH dello sviluppatore finale. Kodak potrebbe anche aver alterato un po' la formula Dektol negli, quanti, 85 anni? da quando è stato pubblicato il D-72, ha cambiato la proporzione di metolo in idrochinone, per esempio, o il pH tamponato. O potrebbe essere solo che i tuoi ingredienti fossero più freschi del Dektol con cui hai confrontato.

ok, quindi sarebbe meglio se continuassi ad usare il dektol..., l'acqua di diluizione della D72 ha 3 gradi di durezza francese, è la stessa che uso con il dektol è un'acqua per uso alimentare quindi priva di metalli che può interferire, forse dovrei provare a fare una prova per trovare il nuovo fattore che devo usare per calcolare il tempo di immersione della stampa nel vassoio, qualcuno di voi l'ha fatto? Hai esperienze in merito?
Grazie

 

[ags2mikon]

I add about a 1/2 pint of propylene glycol to my tray mix to slow down the oxidation. This is added to d-72 or dektol. Been doing this for many years. I also like Ansco 130. I use it for mostly FB papers and I don't add PG to it. It seems to last a very long time. They add PG to ice cream so it must be good, right?

 

[Philippe-Georges]

Here is E-72, a human friendly version of D-72 I got from Chris Patton (former research technician at the Stanford Hopkins Marine Station)
To my humble personal opinion, this is best replacement for D-72 aka Dektol (and AGFA's Neutol Plus).
I am working with this formula, since AGFA's demise in 2005, to my full satisfaction!

(sorry for it is written in Flemish/Dutch)

 

[maxpina]

Here is E-72, a human friendly version of D-72 I got from Chris Patton (former research technician at the Stanford Hopkins Marine Station)
To my humble personal opinion, this is best replacement for D-72 aka Dektol (and AGFA's Neutol Plus).
I am working with this formula, since AGFA's demise in 2005, to my full satisfaction!

(sorry for it is written in Flemish/Dutch)

Thank you very much for the answer and the recipe, in which dilution do you use it? In your opinion, using it for multigrade polythene papers (Ilford RC Deluxe) how long in immersion in the tray? Today I use the appearance time and I multiply it by the factor 10 and I get the total development time, how do you behave with the E72? Thank you very much for your availability.

 

[Philippe-Georges]

Thank you very much for the answer and the recipe, in which dilution do you use it? In your opinion, using it for multigrade polythene papers (Ilford RC Deluxe) how long in immersion in the tray? Today I use the appearance time and I multiply it by the factor 10 and I get the total development time, how do you behave with the E72? Thank you very much for your availability.

As I work solely on FOMABROM FB 111 and like very deep blacks and intense 3/4 tones, I delude this stock as 1+1 (= 2L) at 22°C for 3 min., but you can mix this directly in the work dilution, which its standard is 2,5L, and use it at 20°C for 2 min.
I have no idea how to use it with Ilford RC papers, but I would suggest some trial and error in the standard 2,5L work.

This formula has the strange characteristic to get a little 'stronger' after some use, and then falls flat...

 

[Tom Kershaw]

This formula has the strange characteristic to get a little 'stronger' after some use, and then falls flat...

One of the reasons I make up DS-14: https://www.photrio.com/forum/threads/paper-developers.185029/post-2504964