D-76 Stock times for Tri-X (400TX)

[michaelbothager]

Hello all

Could not find anything conclusive in the archive, or my search skills are lacking.

The official Kodak development times using D-76 in stock/full strength are different between the Kodak tech data sheets.

D-76 data sheet (J-78, December 2017) says 8 minutes at 20C.

Tri-X data sheet (F-4017, December 2016) says 6 3/4 minutes at 20C.

Is it correct to assume, that the D-76 data sheet of 8 minutes is for the older version of Tri-X?

I know that the times are just a starting point, but I would like to understand the reason behind the difference.


All the best
Michael

 

[Don_ih]

Is it correct to assume, that the D-76 data sheet of 8 minutes is for the older version of Tri-X?

I found a 1981 sheet online that says 8 minutes at 20 degrees. So that must be the old time. Alaris needs to update the D76 sheet.

 

[pentaxuser]

I found a 1981 sheet online that says 8 minutes at 20 degrees. So that must be the old time. Alaris needs to update the D76 sheet.

OP, what Don has said is true but I wouldn't hold my breath waiting for Alaris to do so. The Massive Development Chart lists both the 320 and 400 speed. It has the 320 at 8 mins and the 400 at 6.75 So based on what you have found it looks very much as if the correct time for 400 is 6.75

pentaxuser

 

[MattKing]

As Kodak Alaris no longer has any role with respect to D-76, I wouldn't expect to see any update from them with respect to a D-76 datasheet.
Of course, with the current Sino Promise situation, it may be the case that no one will ever produce Kodak D-76 anymore.
If you look at the contrast index graphs on the Tri-X datasheet, you will notice that they provide data for a number of different contrast indices. It may be the case that the tables in the two datasheets are referenced to different contrast indexes.

 

[pentaxuser]

Of course, with the current Sino Promise situation, it may be the case that no one will ever produce Kodak D-76 anymore.

Matt, Adox mentioned plans for making D76 in its replies yesterday to a thread on the state of play on "Kodak" chemicals

pentaxuser

 

[MattKing]

Matt, Adox mentioned plans for making D76 in its replies yesterday to a thread on the state of play on "Kodak" chemicals

pentaxuser

In which case, it will be Adox D-76, not Kodak D-76, and will require its own developing times.

 

[Paul Howell]

For what it is worth, Ultrafine lists 6 2/3 at 68 degrees for both D76 and their clone.

 

[Don_ih]

In which case, it will be Adox D-76, not Kodak D-76, and will require its own developing times.

D-76 is Kodak D-76. It's their formula. If the times are different due to the manufacturer, then they need to call it something else. Like A-76 or Adoximetolquinoniborax Film Developer.

Whatever other magic ingredients Kodak put in their envelopes didn't make it behave any differently from a homemade batch from the known published formula.

(From one of Kodak's Photographic Handbooks)

 

[pentaxuser]

In which case, it will be Adox D-76, not Kodak D-76, and will require its own developing times.

OK Matt. Have it your way. Here's what Adox said and I should have said it was in the XT-3 thread and not the SinoPromise situation one

"This is why we also start manufacturing D-76"

How do you or any of us other than Adox know if the developing times will be different? Adox may well call it Adox D76 I think I might if it were my chemical to establish it as my own but as Don seems to say it may be the same for all intents and purposes

If I were a user of Kodak D76 then as long as Adox makes it so it waddles the same way and quacks the same way as Kodak D76 then as far as I am concerned it is the same duck

I'd be surprised if the vast majority of users feel any differently

pentaxuser

 

[MattKing]

D-76 may very well be D-76, but the mix (which may contains things like chelating agents and other additives) that is chosen by Adox, and in particular the concentration that Adox chooses for the the stock solution can easily result in development times that would vary from the historic times specified by Kodak.
The same applies to the target Contrast Index chosen by Adox.
And of course, the Kodak D-76 makes use of a patent that allows it to be shipped in a single packet - something that Ilford was prevented from doing with ID-11. Whether or not Adox has access to that single packet technology, or has its own replacement for that, or even is content to ship it in two packets, all factors into whether the Adox D-76 is different from the Kodak version.
The difference is one of practice and adjustment. I've little doubt the end results can be adapted to eventually be functionally similar/identical to the Kodak version. Just don't expect to be able to switch one for the other and immediately get exactly the same results - "dialing in" will be necessary.

 

[Don_ih]

I would fully expect Adox Spirit of 76 to give results identical to Kodak D76 with the same processing times. D76 isn't a magic potion.

 

[Paul Howell]

There are many D76 clones, when was the last time Kodak or any of the folks who made Kodak branded chemistry updated any of the Kodak formulas? Legacy, Ultrafine, Photographers Formulary "improved" D76 list the same time as standard D76 for Kodak films. Not to mention ILford ID 11.

 

[MattKing]

Legacy, Ultrafine, Photographers Formulary "improved" D76 list the same time as standard D76 for Kodak films. Not to mention ILford ID 11.

Which ones?
As this thread highlights, there are at least two sets!

 

[Duceman]

And of course, the Kodak D-76 makes use of a patent...

I'd have to think that by now any such patent has expired?

 

[MattKing]

I'd have to think that by now any such patent has expired?

Undoubtedly - but that prevented Ilford from emulating it with ID-11. As I posted, if "Adox has access to that single packet technology", they may be able to emulate that as well.

 

[Don_ih]

It really doesn't matter if Adox can make D76 in a single or 4 different packets - for the end user, it's the same amount of effort. Kodak needed a single mix because they offered this stuff in 1 litre, one gallon, five gallon, and barrel amounts. Adox won't be doing it.

As for which clones have the same times as Kodak? All of them. D76 is D76.

 

[Bill Burk]

The time-contrast curve tells you what you can expect from different processing times without the narrative.

 

[Paul Howell]

Which ones?
As this thread highlights, there are at least two sets!

All list 6 3/4 for stock at ISO 400 68 degrees.

 

[MattKing]

All list 6 3/4 for stock at ISO 400 68 degrees.

From the most current 2017 datasheet for D-76:

The 2002 D-76 datasheet, and the 1999 Tri-X datasheet have the same times.

 

[Don_ih]

From the most current 2017 datasheet for D-76:

Matt, the entire point of this thread was to talk about the discrepancy between the time stated in that data sheet (which needs to be updated to say 6.75) and Kodak's own TriX data sheet (which already says 6.75 - as opposed to the old one, from the previous version of the film, which said 8).

In other words, that data sheet is wrong.

 

[MattKing]

In other words, that data sheet is wrong.

Or references a different target contrast index.

 

[Don_ih]

Ok, so the data sheet is all screwed up. The time given for Tmax 100 is significantly different (2.5 minutes longer) from the time given in that film's data sheet. The time for Tmax 400 is a mere 30 seconds longer than given in that film's data sheet. And the time given for Plus-X is exactly the same.

Tell me how a "different target contrast index" explains that one.

 

[MattKing]

Different films respond differently to different development times when attempting to attain different Contrast indices.
All of which is immaterial to my original point - look to the developer you intend to use for that developer's documented suggested times. And that includes the version of D-76 you intend to use - Kodak's, Adox's, Ilford's ID-11, homemade D-76 from a recipe, third party clones, whatever. And then fine tune for your needs.
The people who put together their own version of D-76 probably compounded their product and specified a stock dilution with at least one version of a Kodak datasheet in mind. Who knows which one?

 

[Don_ih]

Different films respond differently to different development times when attempting to attain different Contrast indices

Did you not even read what I wrote?

Kodak's d76 sheet:

Kodak's Tmax 100 sheet:

Kodak's Tmax 400 sheet:

Kodak's PlusX sheet:

Kodak's TriX sheet:

Kodak's 1981 TriX sheet:

 

[michaelbothager]

Kodak's 1981 TriX sheet:
View attachment 341328

Don, assuming this is the 400 speed Tri-X in 1981, both stock and 1:1 times matches the times from the current D-76 sheet. To me, it seems likely that the D-76 sheet hasn't been updated when Kodak changed Tri-X to 400TX.

If it is different contrast indices (CI's), as MattKing suggests, I would like to think that Kodak would include this information in both data sheets. I can only find a suggested CI of 0.56 in the current Tri-X data sheet Processing section:

The following starting-point recommendations are​

intended to produce a contrast index of 0.56. Make tests to​

determine the best development time for your application.​

I'm not knowledgable about which CI Kodak would suggest for Tri-X in 1981, hopefully that would also be 0.56, making it consistent. I'd like to believe that Kodak has the same base CI as target for different films to make comparison easier. But this may not be the case.

Thank you all for your insights and comments.