Scan technique reveals secret writing in mummy cases

See also this AMA, running today:

> "Hello! My name is Cerys and I am studying for a PhD in multispectral imaging applied to historical artefacts. This involves capturing images in ultraviolet, visible and infrared light to reveal hidden features, which can no longer be seen by the human eye. I was asked to do an AMA as my research on Egyptian artefacts was released yesterday on the BBC news (http://www.bbc.com/news/science-environment-42357259)

https://www.reddit.com/r/IAmA/comments/7netyj/iama_mathemati...

Why can’t we just put the mummies through a CT or MRI scanner? If the ink used in the writing found here or other components deeper inside the artifact have different densities, a CT scan could detect that and pose no harm to the specimen. Assuming no metal is used in the mummies, MRI or MR spectroscopy could potentially give more insight into chemical composition and differentiate isodense parts.

Whew, we can finally stop using Palmolive soap: https://facesandvoices.wordpress.com/2015/10/28/making-the-m...

What does "these masks" refer to said by Prof Adam Gibson?