AgX;

This has an error in it:

"A developing agent fixed to the very layer is employed, with a dye coupled to it. Being of a colour complementary to the colour the adjacent halide layer is sensitive to. This agent being oxidised, after reducing the exposed halide, has become soluble and migrates with its attached dye into the receptive layer, where they are fixed to form an image in the kind of the imbibition technique."

Where development takes place, the "dye developer" becomes INSOLUABLE due to becoming a quinone. It therefore migrates where there is NO development which thereby forms a positive image in dye.

So, that paragraph is sort of backwards.

There are many more methods of producing B&W and color images by using transfers. This includes a whole series of Kodak patents among others.

Also missing is the fact that after he invented the color material, Land could not get it to work properly and turned to Kodak to develop it under contract. After that, Kodak produced it in their own plant in Rochester until Land could build his own coating machines.

After that, Kodak went on to invent a whole series of instant imaging systems including the ones that were sold, and which used direct reversal images. I've mentioned before that when I left the project, the labs were working on an ISO 3000 instant product with outstanding dye stability.

PE