Quote Originally Posted by Photo Engineer View Post
Thorium also altered the hue of the cyan dye a tad. Jim probably has more on that.

Thorium mordanted paper causes a shift towards green of the Cyan dye, immediately as the matrix contacts the paper. With Aluminum mordant, no shift occurs immediately, but it does hue shift upon drying. The Aluminum mordant (M1) actually seems to have much more capacity to shift the hue in dense areas, whilst the Thorium in the Kodak paper looses its ability to shift hue in denser areas.

- Jim