Can anyone tell me the history of the Mitchell unicube?

I know there's the duocube, but there is a Mitchell Unicube for Subtractive Color Printing that isn't branded Unicolor - but obviously Branded by Bob Mitchell. Did the DuoCube come later? I know Mitchell also was the inventor of the Colorbrrator which I am still seeking and haven't seen one pop up yet - but I was wondering which of these came first, second, third etc.

There was also a book called Color Printing by Bob Mitchell that I thought might be interesting given his critical focus on the subject.

Regards,
Mike

There's a brief mention of the Unicube here:
https://www.photomemorabilia.co.uk/Colour_Darkroom/Early_Agfa.html#anchorAgfa15c

From top of page, right column, go to 1. Printing Agfacolor Negatives onto Agfacolor Paper, 3d item: Early Methods...

Funny you posted this - just today I got my hands on a book Bob wrote himself on color printing for $2 bucks
Colour Printing Petersen's how-to photographic library
Feb 1979
by Bob Mitchell
hardcover
ISBN/0-8227-0101-4

Here's the history.

mklw1954 said:

There's a brief mention of the Unicube here:
https://www.photomemorabilia.co.uk/Colour_Darkroom/Early_Agfa.html#anchorAgfa15c

From top of page, right column, go to 1. Printing Agfacolor Negatives onto Agfacolor Paper, 3d item: Early Methods...

Click to expand...

This photomemorabilia website is great ! Everything about early color processes, British photo history . Love it.

I used to have a softcover copy of Color Printing and I have a Unicube set, both of which were included with a Uniroller and drum set purchase, but I've never used them. I do test prints when needed but exposure times and filtration rarely vary as I do consistent film development and limit the films used.

It's unfortunate that the amazing amount of effort, detail, and art developed for analog film and print development, as indicated in the photomemorabilia site, has been rendered obsolete by digital.