The film had a black and white contrast “mask” layer between the yellow filter later and the green sensitive layer. The mask layer was a very slow speed, blue sensitive emulsion, too slow to be affected by any camera exposure. The film was processed to form a dye negative image in each of the three colour coupling layers. The film was then exposed to blue light through the base, printing the already developed cyan dye and magenta dye layers onto the mask layer. The exposure did not affect the blue sensitive top layer because the yellow filter , underneath the blue sensitive layer would “stop” any blue light. The mask layer was then processed in a soft working black and white developer to form a weak positive mask image of the shadow areas of the green sensitive layer and red sensitive layer. The exposure of this layer took place after the film had passed through the Bleach bath. The idea was, when the negative was printed onto Kodacolor paper, obviously through the base of he film,the mask would have held back some of the exposing light from the shadow areas of the negative, thus lowering the contrast. The processing sequence may have been something like the one used for the original Kodacolor film outlined above but with additional steps.
[TABLE="width: 80%"]
[TD="width: 50%"]Developer[/TD]
[TD="width: 50%"]Forms a dye image in the three colour coupling layers[/TD]
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[TD="colspan: 2"]Stop-bath or Wash[/TD]
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[TD="width: 50%"]Bleach[/TD]
[TD="width: 50%"]The Bleach bath converts the exposed and developed metallic silver (camera exposure) to silver halide so it can be made soluble in the Fixer. The Bleach works only on the exposed, developed silver halide so the mask layer is unaffected[/TD]
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[TD="width: 50%"]Re-Exposure[/TD]
[TD="width: 50%"]The film is re-exposed to blue light to print the two developed dye forming layers onto the mask layer. The film is exposed through the base[/TD]
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[TD="width: 50%"]Black and White development[/TD]
[TD="width: 50%"]The Mask layer is developed in a soft working black and white developer[/TD]
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[TD="colspan: 2"]After black and white development and before fixing the film may have looked like this from the emulsion side downwards:
Yellow layer – Bleached exposed silver halide.
Yellow Filter - Still present.
Mask layer - Developed but not fixed.
Magenta layer – Bleached exposed silver halide.
Cyan layer – Bleached exposed silver halide[/TD]
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[TD="width: 20%"]Fixer, performs the actions itemised:[/TD]
[TD="width: 50%"]1. Colour Negative. Removes silver halide formed by Bleach in exposed dye layers to leave pure dye.
2. Colour Negative. Removes silver halide in unexposed dye layers.
3. Black and white positive mask. Removes silver halide in unexposed black and white layer to leave positive mask.
4. Removes yellow filter layer (or it is also possible that the yellow filter layer might have been removed in a separate bath inserted between steps 8 and 10 (see below), or it may have been removed in the black and white developer.[/TD]
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[TD="colspan: 2"]The Fixer leaves exposed metallic silver in the mask layer as this was not turned into removeable silver halide in the Bleach. All silver halide is removed from the negative dye forming layers to make a colour negative.[/TD]
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