In the following you will find illustrations of further examples, including grayscale X-RAY TAGs.
Not all of the examples shown here are X-RAY TAGs readable at 140 keV. Although some plates were made using a similar process, they use other metals, such as brass, as the metal component and would not be as clearly visible when X-rayed.
However, the brass plates look much better and could also be used for decorative purposes, for example.
Hokusai’s Big Wave at Kanagawa.
As gray scale X-RAY TAG (l) and an hi-res x-ray image thereof (r).
Once again the large wave, slightly modified, but here designed as an X-RAY TAG and viewed with a baggage scanner (l), as well as the template for this (r):
MC Escher’s “Water and Air”:
X-RAY TAG and brass version (approx. 10 x 10 cm)
MC Escher’s, “Fishes and Scales”:
The template image, the brass version, as X-RAY TAG and a luggage scan of the X-RAY TAGs, placed in a suitcase.
von MC Escher
Below is an X-ray image of several grayscale X-RAY TAGs, optimized for 70 keV and taken with an X-ray machine for veterinary purposes.
u.l.: Herr Prof. W. C. Röntgen, u.r.: image of a/my cat
l.l.: one of the earliest x-ray images (“Hand A.K.”), l.r.: x-ray of a cat
And here are greyscale X-RAY TAGs optimised for 140 kEV, taken with a high-resolution X-ray system for materials testing.
From left to right: Photo cat, X-ray image ‘Hand A.K.’, portrait of St Christopher with child (after Dierick Bouts, triptych ‘The Pearl of Brabant’, Alte Pinakothek, Munich).
QR codes can also be displayed. Here is a test sample and the corresponding X-ray scan with a high-resolution system.
And again the image of Prof. Röntgen, similar to the one above, but optimised for 140 keV, and scanned with a baggage scanner:
Another method to display gray scale images is currently under development. More on this here.