CODE UNCOVERED...
The top left of the page encompassing the MRGO sequence shows some very interesting examples of letters and numbers, they are grey against grey so a little difficult to view at first but once your eyes have become accustomed to the shades of color, you should see it all quite well.
In the next image, I have highlighted the areas concerned:
This image came from the double negative Code Page previously published,
https://tamamshud.blogspot.com/2023/10/tamam-shud-mystery-75-year-old-code_11.html?sc=1697267269643#c44304934965899696
https://tamamshud.blogspot.com/2023/10/tamam-shud-mystery-75-year-old-code_11.html?sc=1697267269643#c44304934965899696
Where this technique differs is that we don't have two layers of ink and then penciled code, we have three layers of colour. The top layer whilst dark, is lighter than the next layer which has the penciled code. This penciled code is a lighter colour again but when it is written on top of the lower layer of ink, It has the effect of making the already dark lower layer marginally darker again but in the shape of a tiny letter or number.
I am sure you can see the end results of this latest photograph, there will be another 6 or 7 images yet to be published in this series, each focusing on different areas of the code page.
Inkjet printers are super sensitive to the various shades of colour and by using a solution of citric acid, we can remove the upper layer of dark ink leaving the lower two layers showing..
In this case, though, the code we are seeing is not quite the same. This code, if that is what the letters and numbers represent, is made up of markings in plain sight that have been obscured by the negative image of the code page.