Dupont Defender 16d Developer

[jayabbas]

Does anyone know the chemical make up of Dupont 16d developer? My 1946 Dupont formula book shows formula for 15d but not 16d. I have a can of the stuff I'm itchin to mix up and soup some film. Perhaps it was a proprietary blend that came out later in time. I'm guessing a comparable product would have been Kodak DK-50. Also anyone can chime in with thoughts on using old powdered developers in sealed metal cans -- stuff seems to last forever if kept dry. Thanks

[David Lindquist]

Does anyone know the chemical make up of Dupont 16d developer? My 1946 Dupont formula book shows formula for 15d but not 16d. I have a can of the stuff I'm itchin to mix up and soup some film. Perhaps it was a proprietary blend that came out later in time. I'm guessing a comparable product would have been Kodak DK-50. Also anyone can chime in with thoughts on using old powdered developers in sealed metal cans -- stuff seems to last forever if kept dry. Thanks

It looks like you are right about this being a proprietary formula. Information in my Photo-Lab-Index dated 1972 says "Du Pont 16-D is a prepared developer, the formula for which is not available for publication." It's further described as a "Versatile General Purpose Film Developer" and "...recommended for use with Du Pont 'Cronar' photographic sheet films." ("Cronar" was Du Pont's name for the base their sheet film was coated on, I expect it was similar to Kodak's "Estar" base.) In addition 16-D is described as a "fast, clean working developer with a long tank life. Negatives developed in 16-D have a neutral colored image of medium-fine grain." The developer was to be used full strength. It came in units to make 1 gallon or 3 1/2 gallons of working solution.

I suppose one risk of using it is that you might find it's the most wonderful film developer you've ever tried and you'll have no way of reproducing it. ;)

David

[Merg Ross]

It looks like you are right about this being a proprietary formula. Information in my Photo-Lab-Index dated 1972 says "Du Pont 16-D is a prepared developer, the formula for which is not available for publication." It's further described as a "Versatile General Purpose Film Developer" and "...recommended for use with Du Pont 'Cronar' photographic sheet films." ("Cronar" was Du Pont's name for the base their sheet film was coated on, I expect it was similar to Kodak's "Estar" base.) In addition 16-D is described as a "fast, clean working developer with a long tank life. Negatives developed in 16-D have a neutral colored image of medium-fine grain." The developer was to be used full strength. It came in units to make 1 gallon or 3 1/2 gallons of working solution.

I suppose one risk of using it is that you might find it's the most wonderful film developer you've ever tried and you'll have no way of reproducing it. ;)

David
Ah, good answer. I thought that 16-D sounded familiar and that there would be more information about it; being a proprietary formula explains why that is not the case. I used 16-D in the late 1950's and early 60's with Cronar Press sheet film (Du Pont). I was shooting 8x10 and contact printing, so grain was not a concern. I don't recall anything remarkable about 16-D, but it worked fine and yielded good negatives. I assumed that it was a typical MQ developer. I recall that it came in a red can (how's my memory?).

[Drew Wiley]

I've seen the forumla somewhere, but don't think I kept it. It was a fairly ordinary MQ tweak of limited interest to me personally. My older brother once used it in tanks for
Super-XX.

[Lynn Jones]

As several of you note, it was an unpublished propietary formulary. I dug through three Photo Lab Index books that were 50 and more years old. It was intended as a standard large format film developer. I have used it a few times in the 1950's but is about the same as DK50/DK60A as I recall it.

Lynn

[jayabbas]

Ah, good answer. I thought that 16-D sounded familiar and that there would be more information about it; being a proprietary formula explains why that is not the case. I used 16-D in the late 1950's and early 60's with Cronar Press sheet film (Du Pont). I was shooting 8x10 and contact printing, so grain was not a concern. I don't recall anything remarkable about 16-D, but it worked fine and yielded good negatives. I assumed that it was a typical MQ developer. I recall that it came in a red can (how's my memory?).

The cans I have are the 3.5 gal mix and are the Dupont green. I also have the 1 gal replenishment can and that is the familiar red though much smaller in size. Thanks for your input on this developer.