Someone suggested (thank you) that it might be too much water mixed in with the pigment. I didn't use much dilution to begin with because Akua colors are already pigment dispersions. But just to humor myself, I tried re-printing all 60 blue skies and lake prints on the paper in question. All went well, in fact the blue was too strong for my plans but I figured it was bound to fade a little and would match the rest of the edition after drying.
Next day, ultramarine disappeared, but this time left me with 23 good prints, nicely faded blue, and 37 prints mysteriously refuse to "take" my renewed effort. With this kind of ratio, I figure if I print the blue daily, eventually, they will ALL stick. Or else I will develop amazing triceps. In any case, I sure wish I knew what the dickens is going on because the results of my experiment yield nothing. This is not only the same paper, some take and some don't, but they are random pieces of the same sheet of paper, that is, I tore one very large sheet of paper to make little pieces for this print.
But see for yourself. First shot is the Kihada, second is the New Hosho. Sky blue gone, red faded, purple faded.
One more for kicks, this is the latest shot of the two papers, after one day of reprinting the entire Kihada set. Top is New Hosho, bottom is Kihada. Beats the heck out of me! And why only a portion of the run faded out? I printed everything in one sitting, same pigment, same rice paste...