Hi,
I am not saying that I have done a lot of it, but made (there was a url link here which no longer exists) with the process.
I always like duotone quality with warmer highlight and cooler shadow in prints. I also do gum over platinum which certainly gives you more option in terms of color of choice.
I printed platinum/palladium first. I think it is good idea to keep the show open at this stage since a layer of blue will significantly darken the shadow value.
I may even suggest to dilute the cyanotype solution as blue takes over the image very quickly. Again, I am saying this in context of attaining duotone prints. You can certainly go further with cyanotype like Izu's prints which are gorgeous by the way. I saw the book, but simply does not do justice.
Registration becomes an issue as the size of negatives become larger since unlike gum, the cyanotype really imprints the image. I was making prints from 3x4 so it did not create so much of problem. You can use Fabriano Artistico for it as gum over people use to avoid the problem.
If you use acid solution for cyanotype, you can create more shades in highlight. So this may be something to take into consideration depending on what you want.
What I was curious was that how this will compare to gum-over pt/pd prints. It definitely bring the Persian blue more. I would like to see if this has any effects on the smoothness of the images. It may bring more grain to the prints. Lately, I have been too preoccupied with the business, and have not printed much to be honest.
Regardless, a great thing is that you can gain the smooth tonality of platinum/palladium with a hue of deep blue.
Hope you will have fun with the process.
Warmly,
Tsuyoshi
Note on image: on screen, it may not be right in terms of color, but on print, the body has warmer as well as cooler tones in it.
