CD-4 in glycol

[koraks]

It was me who made the remark on the color, not @Rudeofus. And while your experiment seems successful, I personally agree with @Rudeofus that a week is short, and that it's kind of difficult to judge results online. But this result is certainly encouraging and I'm sure many people follow your progress with great interest. I certainly do. So there's no need for the somewhat acrimonious tone

 

[bnxvs]

English isn't my native language. I apologize if my opinion was too acrimonious. My goal was to show that the reagent is completely fresh and the color of the solution in glycol does not mean that the reagent was oxidized. By the way, when concentrate dissolved in water, the color disappears. Unused working solution is transparent.
Let's get back to the question in a month.

 

[koraks]

No worries! I'm genuinely interested to see how the experiment proceeds. So far, so good, it seems!

 

[bnxvs]

So ... Exactly one month. I prepared a working solution (stephan4u contributed C-27 formula).
No comments...

 

[koraks]

This is very promising indeed!!

 

[bnxvs]

I left some more concentration. I'll let him stand for some more time - and if I don't forget, then after 3-4 months I'll repeat the test. But now I can confidently say that glycol is a very good preservative for CDs.

 

[Raghu Kuvempunagar]

I left some more concentration. I'll let him stand for some more time - and if I don't forget, then after 3-4 months I'll repeat the test. But now I can confidently say that glycol is a very good preservative for CDs.

Hello @bnxvs, just curious to know if you tested again on a later date as you intended? What were the results and what's your conclusion on the viability of glycol as a solvent for CD-4 wrt long shelf-life? Thanks in advance.

 

[bnxvs]

Unfortunately, the Life again made its own adjustments to my plans. I was forced to stop my experiments due to moving to another country...
Perhaps in the spring I will be able to restore my laboratory and bring this matter to an end.

 

[mohmad khatab]

Unfortunately, the Life again made its own adjustments to my plans. I was forced to stop my experiments due to moving to another country...
Perhaps in the spring I will be able to restore my laboratory and bring this matter to an end.

I hope you are fine and safe
I hope you will return to your lab work as soon as possible

 

[kfed1984]

I left some more concentration. I'll let him stand for some more time - and if I don't forget, then after 3-4 months I'll repeat the test. But now I can confidently say that glycol is a very good preservative for CDs.

Mind sharing your C41 formula?

 

[koraks]

Mind sharing your C41 formula?

I think he was using @stefan4u's C27 formula back then.
When I was in a similar situation to yours, I rooted around for all manner of color formulas. Not too long ago, I assembled the whole thing here: https://tinker.koraks.nl/photograph...lor-developer-formulas-including-c41-and-ra4/
On that page I link to the C29 formula, which is a minor improvement from the C27 formula used above: https://www.photrio.com/forum/threads/color-negative-developer-near-to-c41.42731/

I never tried storing CD4 as a concentrate in glycol; just never got round to it!

 

[kfed1984]

I think he was using @stefan4u's C27 formula back then.
When I was in a similar situation to yours, I rooted around for all manner of color formulas.

Yes I saw your site, but didn't think that recipe would be there. I'm not sure why it may be easier to dilute CD4 in glycol vs. weighing it manually on a milligram scale.
From what I gathered so far, it may be easier to use the developer one shot as the CD4 is the only expensive thing that goes in it, and it can be weighed out accordingly, and we don't need any fancy developer chemicals for keeping it as it's used quickly in one use.

The bleach however is quite concentrated in the expensive EDTA and I definitely don't want to use it one shot. If the bleach and fixer baths are kept separate, do they have good keeping properties, if replenished?

 

[koraks]

If the bleach and fixer baths are kept separate, do they have good keeping properties, if replenished?

Yes. Well, the bleach does. The fixer less so, but that's cheap anyway.

I'm not sure why it may be easier to dilute CD4 in glycol vs. weighing it manually on a milligram scale.

It's a convenience thing; it's generally quicker to measure out e.g. 20cc of a liquid than measure out e.g. 2.0g of a powder.
On the blog post of mine I linked to there's a set of concentrate formulas for C41 which I used for some time. It used 3 stock solutions, easy to measure out and just add water, and then add the required amount of CD4 measured out as dry weight. This was a sort of best of both worlds solution for DIY C41 with good keeping properties.

 

[bnxvs]

C-42 is Kodak's home-version of C-41?

As I said, a few color oddities. But then going from a CD3 process to a CD4 process is easier, but going from CD4 to CD3 is much much more difficult in terms of dye formation. I have done both types of cross processes. PE

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