Step ladders, stippling judders and looking wobbly.
There is without doubt extremely good value to be found in the content and comments on Cipher M and Gordon’s blog, the problem is that there are so many of them, and if anyone responding dares to enter the world of technicalities they do so at their own peril. Nevertheless, this is what we have.
1) The Rubaiyat page was photographed under UV light, and developed onto a glass plate yielding a negative, which was then written on with some kind of white pen. This was then printed (reversing it again), yielding what we see. (NP)
2) The Rubaiyat page was photographed under UV light, and developed onto a glass plate yielding a negative, which was then printed as a photograph. This photograph was then written on with a back laundry pen, and it was this modified photograph that was then shown to the newspapers (for them to photograph themselves). (NP)
3) You can see the same (what you call) “step-ladder effect” on lots of the other letters, including the (in)famous Q, so the answer here is surely most likely to be something pretty physical and basic. To my eyes, I see someone slowly dragging a old-fashioned laundry pen across a writing surface (perhaps an IR photograph), where the judders get translated into what you call “steps”. The N and E look wobbly in the same way a fair few other letters look wobbly: so perhaps the more testing case is the A, which seems not only smoother (no steps), but also as though the writer has gone over it at least twice. (Maybe the first pass was too soft, and so needed doing again?) (NP)
4) UV light was (and is still used) to show up what the Police found i.e. indentations in the paper of the book. It was these indentations that were traced over by the Police. UV light was used during WW2 and in the Cold War years by censors to examine mail. (GC)
5) I suggested then that the markings would have been done on acetate or glass and certainly not directly on to the page itself. (GC)
This is our data: 50 characters marked up on acetate or glass and photographed.
Some of the characters in the above code appear wobbly or stippled when viewed close-up. Some are smooth. Many have been marked over more than once and the instrument (pen or brush) used by the individual(s) responsible was wet with ink, leaving pooling at the end of the some strokes (fig:2, letterA)
I count 16 ‘judders’ on the P curve alone.
I count 46 wobblies on the letter R.
Is it reasonable to ask if the mark-up served two purposes: to show the faintly written pencilled code in clear as well as disguise what it consisted of ?
There’s a word for that method but it escapes me.
Thanks to NP and GC for their work, appreciated. Any errors are mine.