Some years ago I visited with Mike Rosenberg and had a chance to see his work and understand the methodology of his QTR profiling system. I sure did not see any "bleed through" on his prints.
I found the method interesting and eventually adapted it to my carbon printing, and have since taught a highly modified version of this method in my carbon workshops, and to my friend Sam Wang for silver printing, and Sam and Chris Anderson for cyanotype. One of the important adjustments I make with the basic profile is to adjust the blocking density for each process so that the main ink blockers are used at a percentage that blocks equal light, which varies of course according to process and exposing light. This practice minimizes the appearance of grain.
My opinion is that in blocking it does not matter if it is done with silver or pigment. If you put down enough of either to get the same transmission DMAX on the negative, the result should be the same, and it always has been so in my experience.
If interested, I describe what I do in a folder on the carbon forum at groups.io. https://groups.io/g/carbon/files/QTR...bon%20Printing
Sandy
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