Interesting note in LF 6/1957

[Lanthanum]

Hello all!

I came across this note on page 262 of Leica Fotografie 6/1957 and was wondering if anyone knew the formula/product to which it refers?

One-time Development of Colour Negatives ... ?

Towards the end of October Willi Beutler gave a demonstration in Hamburg of a simple method of developing colour negative films in daylight developing tanks. He demonstrated how films of any make could be developed using a single phial containing about an ounce of developer concentrate (working- strength dilution one part to 500 of water and discarded after each film is developed). The developer composition was not revealed, but the quality of the negatives seemed to be good. It is claimed that the method cuts across the jungle of patent restrictions, eliminating the use of expensive bulk-mixed developer solutions which have hitherto deterred the small finisher undertaking the processing of small quantities of colour film. Amateurs, too, can avail themselves of the new developer.

10X8-in. colour enlargements from Leica colour negatives were handed round for inspection after the demonstration. These prints were particularly sharp, with a noteworthy rendering of blacks and grays. For these positives Beutler does not use a bleach bath and claims to have found a method of utilizing the silver image as an integral colour mask. The demonstration was attended by professional photographers, dealers, and representatives of the photographic industry.​

 

[Rudeofus]

David Lyga posted a (there was a url link here which no longer exists) a while back here on APUG. While this is not from a single concentrate, one could even consider full strength C-41 CD as the concentrate here, AFAIK it lasts for several months. And it contains a detailed description how to mix and use it yourself!

PS: waiting for the imminent discussion of "but tests strips are off with this procedure!!!" ...

 

[AgX]

To avoid confusion, this is NOT about single-bath colour processing, but about a single-concentrate colour developer.

I think the formula is revealed in german literature. But I have not got it at hand.
Though another source called it a two-part concentrate.


One means to achieve a single-part concentrate would be emplyoing a base of the developing agent and dissolving it not in water (where it would hardly be soluable) but instead in a certain alcohol, which itself is well soluable in water. By this a small volume of a highly concentrated colour developer can be achieved.

 

[Lanthanum]

Very interesting Rudeofus and AgX, I have so much to learn

Thank you for your contributions.

It would be so handy to be able to use such a small volume of concentrate for one-time processing. Curious about the "...claims to have found a method of utilizing the silver image as an integral colour mask"?

 

[Lanthanum]

Adox Colorfin

It looks like Adox collaborated with Willi Beutler to bring this to market in late 1958! I should have some more details soon...

 

[AgX]

Yes, I meanwhile found a review from february 1958 in my printed matters.

-) made by Adox as Adox Colorfin, to make CN film developing as easy as b&w

-) single concentrate CD

-) developing at 20°C for 14-20min, may be varied to control the contrast

-) 1min rinse

-) selfmade neutral Fix from Hypo from the pharmacist for 5min

-) few minutes rinse in the tank under running water

-) selfmade bleach from Hypo+Potassium ferricyanide from the drugstore for 5-7min

-) final rinse for 30min

 

[Rudeofus]

You could trivially sell C-41 as a single concentrate, but shelf life would be limited to a few months. Few outfits would put such a product in their shelves these days, but a few decades ago this would have been a viable option.

People here on APUG have used Tetenal C-41 CD for (there was a url link here which no longer exists). Some of Tetenal's color developer products have been specifically re-engineered for longer working solution shelf life, so there are ways to go with single concentrate CD.