Actual pictures will be the real test of the digital negatives, but there are things that are a lot easier to learn from printed step tablets. Complicating matters here is that I haven't done much printing for a while because I was busy with other projects and in the meantime my old favorite papers no longer work well. The good news is that there are now two papers being made specifically for platinum printing, and both have looked promising when we've used them at my platinum workshops at CAP. The bad news is I haven't used them enough to know all the quirks and tricks needed to get the best results from them. So, I'm basically testing/exploring the two papers at the same time I'm testing/exploring the digital negatives. Just the opposite of working with a single variable at a time.
Two negatives about 4x5 inches set on the prepared sheet of paper, placed in the vacuum frame. Once the frame is powered up it gets swung up vertical, against the box of UV light tubes.
On top is a straight negative print of the step tablet file. Below, a negative made with the tonal scale adjusted to bring it into line with the sensitometric response of the Pt/Pd print mixture on this paper. The red strips are Rubylith, which is totally opaque to UV light. They are placed to overlap the top row of the tablet where there are patches at 10% and 0% density. The area under the Rubylith gets no exposure at all, so I can compare those very light patches to pure paper white once the print has been processed and dried.