Dektol vs D72 (My Observations)

Dave Krueger · Feb 1, 2021

When the quality problems with Dektol began, I started looking for reliable alternatives, of which there are many choices. But, being used to Dektol, I decided to start mixing D72 myself. Sure enough, its performance matched Dektol closely. I didn't even have to recalibrate my Zonemaster enlarging meter. But I noticed the D72 would turn brown sooner than the Dektol which leads me to think that Dektol and D72 are not really clones of each other. Because of that, I tried mixing ID-62 and also bought some Freestyle powder paper developer, both of which also turned brown sooner than Dektol (but no sooner than the D72). The discoloration did not seem to result in any noticeable loss in potency.

The above is just based on my own observation and not on precise measurements.

Then....

I came across this:

This old advertisement seems to explain why Dektol discolors less than D72. I'm not really posting a question so much as an observation. Given that the ID-62 and Freestyle paper developers discolored as much as the D72, I will probably revert to mixing D72 simply because I prefer M-Q rather than P-Q formulas.

My specific circumstances: I mix up paper developer to working strength (1+1) immediately and keep it in closed full one-gallon containers until I need it. I then use it for multiple developing sessions over 1-3 months. I throw it out after about 100 RC 8x10s. I do pay attention to emergence time, but it doesn't change that much at that concentration and quantity. The discoloration, presumably due to oxidation, doesn't seem to have much impact on performance under these conditions. If it did, I think I would notice my Zonemaster calibration being inaccurate.

My conclusion is that Dektol is different (better) than D72, at least in terms of appearance over time, under the specific circumstances outlined above.

No, I can't remember where I came across the Dektol ad. Maybe Pinterest or Flickr.

Donald Qualls · Feb 1, 2021

Discoloration not affecting performance seems to match Dektol, as well. I have some (expired in the late 1990s) that was mixed in 2006 or so, at double strength (i.e. I used half the water), and stored in sealed glass (pickle jars). I used some last May (1+9 for film), and it still worked at MDC times, despite a color in the jars darker than strong tea (though a little lighter than cola or coffee). This longevity is probably largely due to the double sulfite concentration.

Note that this Dektol was on the dark side when freshly mixed; I figured that was because the bag was old -- but I've seen no indication of problems. When it runs out, I'll probably mix D-72 myself. I've got no problem with PQ vs. MQ, but metol's cheap and dissolves more easily than phenidone.

Dave Krueger · Feb 1, 2021

Actually, all the paper developers I tried had no discoloration until I used them for the first time. Of course, my paper developer gets used relatively quickly. If I were to leave it untouched for years, I'm sure it would turn brown. I do like mixing D72 because I can mix it to working strength in the quantity I need. In any case, it's good to hear that someone else doesn't experience diminished performance from the discoloration.

You're probably be right about the sulfite. Seems to me that bags of Dektol have much more powder in them than other packaged chemicals or the stuff I mix myself.

MarkS · Feb 1, 2021

Dektol likely has sequestering agents in it to allow packaging as one powder, and possibly some preservatives. That could explain the 'extra' weight in the packet.

voceumana · Feb 1, 2021

Commercially available developers often include agents to address cosmetic and other non-functional issues just to prevent customer complaints. And, of course, any single package developer is likely to include sequestering agents to give it long shelf life.

It doesn't make them better, it just addresses commerce issues.

Dave Krueger · Feb 1, 2021

MarkS said:
Dektol likely has sequestering agents in it to allow packaging as one powder, and possibly some preservatives. That could explain the 'extra' weight in the packet.

Ah-ha! Good point.

Dave Krueger · Feb 1, 2021

voceumana said:
It doesn't make them better, it just addresses commerce issues.

Sort of like when Henry Ford decided to produce cars in colors other than black, right?

I see your point, but if Dektol differs from D72 only in the sense that it retains its fresh appearance longer, I would define that as better. But, that's just me. Discolored chemicals look defective to me.

[Edit] Looks like I am contradicting myself. If the discoloration doesn't affect performance, then I should be happy. But, it's also true that the darker color really does bother me, so I find myself discarding sooner than I ordinarily would.

relistan · Feb 1, 2021

I realize that you are saying you like MQ developers and this workflow works for you. If you every consider changing, Ilford Multigrade has had no packaging issues that I have ever read, and is a liquid, so you don't need to pre mix all of it. It preserves very well at working strength (I use it 1+9). Lasts a couple of months in a sealed bottle. The full strength lasts well over a year in a partially filled bottle. It has good capacity, and to my eyes looks pretty much like Dektol. Don't be put off by the name, it has nothing really to do with the paper by the same name, it was originally formulated to solve a problem with PQ Universal with the original Multigrade paper as I recall reading. I use it with ADOX and Ilford papers, plus old Oriental Seagull and Agfa papers, all to good effect. @Greg Davis tested it on his Youtube channel and came to the same conclusion as I did in my personal work: it looks pretty much the same as Dektol.

Dave Krueger · Feb 1, 2021

relistan said:
I realize that you are saying you like MQ developers and this workflow works for you. If you every consider changing, Ilford Multigrade has had no packaging issues that I have ever read, and is a liquid, so you don't need to pre mix all of it. It preserves very well at working strength (I use it 1+9). Lasts a couple of months in a sealed bottle. The full strength lasts well over a year in a partially filled bottle. It has good capacity, and to my eyes looks pretty much like Dektol. Don't be put off by the name, it has nothing really to do with the paper by the same name, it was originally formulated to solve a problem with PQ Universal with the original Multigrade paper as I recall reading. I use it with ADOX and Ilford papers, plus old Oriental Seagull and Agfa papers, all to good effect. @Greg Davis tested it on his Youtube channel and came to the same conclusion as I did in my personal work: it looks pretty much the same as Dektol.

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.

Don_ih · Feb 1, 2021

Every now and then, I mix up a batch of Dassonville D-1 Charcoal Black Paper Developer (formula found in the Darkroom Cookbook, but I reduce the hq by 3 g) -- that stuff turns the colour of molasses.It still doesn't get the black I want - which seems only to exist in Azo or Velox contact paper - but it gets close. You can use it well after it turns coffee-coloured - but it's hard to judge what's happening to the print....

NB23 · Feb 1, 2021

I may be off topic but you might find some utility in my post.

I have been printing a lot over the past 10 months, over 10,000 prints ranging from 16x20 down to 4x5, rc and fb. Just today I have printed 45 5x7 fb matte prints.

I am not economical with the fixer, i go through a lot if it, but I am very economical with my developer. I’m presently tackling 11x14 and 5x7 papers for the foreseeable future and I’m using 2 Liters of Ilford Multigrade developer 1:9 which I just keep topping it up everyday, by approximately 300-500ml 1:9 solution, which is just the amount that I am losing by carry-over into the stop bath in a single session. I’ve been replenishing this way for about 6 months now and I believe that I have saved at least 75% developer versus the way I used it before (which was a mixing a new bath every session).

I have also topped it off with Dektol 1:1 a few months ago. I just keep going, i’ll be adding some polymax-T into it as soon as I’ll use up the multigrade developer. I like to think of it as my secret magical recipe.

Lovely prints. But please don’t ask me if my prints are coldtone or warmtone, I go through a vast amount of different papers and I dip them all into a quick viradon bath, so they all end up warmish.

Dave Krueger · Feb 1, 2021

Don Heisz said:
Every now and then, I mix up a batch of Dassonville D-1 Charcoal Black Paper Developer (formula found in the Darkroom Cookbook, but I reduce the hq by 3 g) -- that stuff turns the colour of molasses.It still doesn't get the black I want - which seems only to exist in Azo or Velox contact paper - but it gets close. You can use it well after it turns coffee-coloured - but it's hard to judge what's happening to the print....

I looked up Dassonville in the Cookbook. I prefer cold tones and also strive for as much Dmax as I can get. I now do selenium 1:20 toning of everything I print, even RC prints. I remember seeing AZO paper in the paper sample book books at photo stores in the 70s. One reason I'd like to stick with a Dektol clone is because I'd prefer not to have to recalibrate my Zonemaster.

[edit] I develop RC prints face down for a fixed time, so a dark developer isn't a technical issue for me. I develop fiber prints face up, but only because of the curl would make it hard to insert them into the developer face down.

Dave Krueger · Feb 1, 2021

NB23 said:
I may be off topic but you might find some utility in my post.

I have been printing a lot over the past 10 months, over 10,000 prints ranging from 16x20 down to 4x5, rc and fb. Just today I have printed 45 5x7 fb matte prints.

I am not economical with the fixer, i go through a lot if it, but I am very economical with my developer. I’m presently tackling 11x14 and 5x7 papers for the foreseeable future and I’m using 2 Liters of Ilford Multigrade developer 1:9 which I just keep topping it up everyday, by approximately 300-500ml 1:9 solution, which is just the amount that I am losing by carry-over into the stop bath in a single session. I’ve been replenishing this way for about 6 months now and I believe that I have saved at least 75% developer versus the way I used it before (which was a mixing a new bath every session).

I have also topped it off with Dektol 1:1 a few months ago. I just keep going, i’ll be adding some polymax-T into it as soon as I’ll use up the multigrade developer. I like to think of it as my secret magical recipe.

Lovely prints. But please don’t ask me if my prints are coldtone or warmtone, I go through a vast amount of different papers and I dip them all into a quick viradon bath, so they all end up warmish.

Doesn't the developer turn dark using this replenishment scheme?

NB23 · Feb 1, 2021

Dave Krueger said:
Doesn't the developer turn dark using this replenishment scheme?

No. I was expecting it would, but no, it doesn’t.

voceumana · Feb 2, 2021

If darker colored developer looks defective that becomes a customer perception commercial issue to the manufacturer and they tend to address such issues--thus, Dektol. There's nothing wrong with sticking with Dektol or going with D-72.

Dave Krueger · Feb 2, 2021

NB23 said:
No. I was expecting it would, but no, it doesn’t.

Sounds like an interesting way to eliminate factorial development times. I don't do very many prints per session, so I would be doing the replenishment after only 5-10 8x10s which would keep the developer strength consistent. And, it would also keep the air space in the container very small. Thanks for posting about this. I will give this some thought.

Dave Krueger · Feb 2, 2021

voceumana said:
If darker colored developer looks defective that becomes a customer perception commercial issue to the manufacturer and they tend to address such issues--thus, Dektol. There's nothing wrong with sticking with Dektol or going with D-72.

Well, I have to admit that the wording of that advertisement seems to support what you're saying.

BradS · Feb 2, 2021

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.

BradS · Feb 2, 2021

Would that PE were still among us.

john_s · Feb 2, 2021

michael_r said:
Yes. PE confirmed this as well (in the case of Dektol/D-72).
If home mixed D-72 is found to discolour more or faster than packaged Dektol, perhaps this is due to lesser purity and/or freshness (more oxidation) of bulk chemicals obtained for home mixing.

Might it be the presence of something like EDTA? I was mixing up some ID-78 after Agfa Neutol-WA was discontinued, and I had noticed that the MSDS for that product included EDTA so I added some to my ID-78 which was slightly tinted and it immediately became colorless and stayed colorless until oxidation built up, at which stage it went brown.

Incidentally, the MSDS docs published here in Australia included more ingredients than those in other countries, presumably because of local regulations.

Dave Krueger · Feb 2, 2021

Thanks, for all the comments, guys. The reason I started this thread was that I have read numerous places that Dektol and D72 were the same and so I thought I discovered that they weren't when I came across that old Dektol advertisement. I'm still confused about the claim that Dektol has "much greater capacity" and "better keeping qualities" over D72 if they are the same, but it certainly is possible that Dektol is made with more pure ingredients than the D72 I mixed up from Formulary chemicals which could account for the discoloration. Water quality shouldn't be an issue since I used distilled water for my last batch.

In any case, I will probably stick with D72, but may experiment with the replenishment scheme described by NB23. I may give Ilford MG liquid developer a try, since I've seen it recommended repeatedly by others, but I have such a long history with Dektol that changing to anything aside from D72 is a bit uncomfortable. If it ain't broke...

By the way, whatever happened to PE?

BradS · Feb 2, 2021

PE died last year. RIP

https://www.photrio.com/forum/threa...rey-aka-pe-photo-engineer-feb-15-2020.173245/

RalphLambrecht · Feb 3, 2021

Dave Krueger said:
When the quality problems with Dektol began, I started looking for reliable alternatives, of which there are many choices. But, being used to Dektol, I decided to start mixing D72 myself. Sure enough, its performance matched Dektol closely. I didn't even have to recalibrate my Zonemaster enlarging meter. But I noticed the D72 would turn brown sooner than the Dektol which leads me to think that Dektol and D72 are not really clones of each other. Because of that, I tried mixing ID-62 and also bought some Freestyle powder paper developer, both of which also turned brown sooner than Dektol (but no sooner than the D72). The discoloration did not seem to result in any noticeable loss in potency.

The above is just based on my own observation and not on precise measurements.

Then....

I came across this:
View attachment 265390

This old advertisement seems to explain why Dektol discolors less than D72. I'm not really posting a question so much as an observation. Given that the ID-62 and Freestyle paper developers discolored as much as the D72, I will probably revert to mixing D72 simply because I prefer M-Q rather than P-Q formulas.

My specific circumstances: I mix up paper developer to working strength (1+1) immediately and keep it in closed full one-gallon containers until I need it. I then use it for multiple developing sessions over 1-3 months. I throw it out after about 100 RC 8x10s. I do pay attention to emergence time, but it doesn't change that much at that concentration and quantity. The discoloration, presumably due to oxidation, doesn't seem to have much impact on performance under these conditions. If it did, I think I would notice my Zonemaster calibration being inaccurate.

My conclusion is that Dektol is different (better) than D72, at least in terms of appearance over time, under the specific circumstances outlined above.

No, I can't remember where I came across the Dektol ad. Maybe Pinterest or Flickr.

it would be interesting to knowthe amount of preservative(sodium sulfite) in each of these developers.

Donald Qualls · Feb 3, 2021

RalphLambrecht said:
it would be interesting to knowthe amount of preservative(sodium sulfite) in each of these developers.

If the bag contents for Dektol is significantly heavier than D-72 for the same solution volume, it's almost certainly due to increased sulfite level -- which would increase both shelf life and capacity, as well as reducing discoloration (all as claimed in the original ad). Sequestrants generally don't amount to tens of grams per liter; nor do most developing agents, but sulfite goes there. For prints, there wouldn't be much if any difference in the development (perhaps a slight cooling of tone due to increased solvent effect, but in two minutes I doubt it would be visible). For film, there might be a slight increase in film speed or change in grain -- but with the usual dilution, I doubt even doubling the sulfite would have much visible effect, either.

richyd · Feb 3, 2021

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.

Dektol vs D72 (My Observations)

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