[kbutler]

I'm trying to figure out what actually happened, technically:

> Some officials use a software programme such as Photoshop to paste a black patch over secret text, obscuring it but not removing it. When documents are edited in this way, normal home or office software can disclose the obscured text

They probably mean Adobe Acrobat, to modify pdf documents.

> The names of officials and outside experts involved had simply been blacked out with a marker pen, and could be read by printing the document and holding the paper up to the light.

Not sure, here - a /software/ "marking pen" that obscured the text, but the underlying text, presumably in a different shade, would be printed by a printer?

Interesting.

[Tarq0n]

Probably editing the pdf in photoshop or illustrator, but not flattening the layers back down before exporting the document, causing the underlying information to be retained. The PDF format doesn't just function as a container for an image, it supports all kinds of layers.

[abstractbeliefs]

In (perhaps another) instance, they set the background colour of a section of text to black, meaning the black text was not readable, but could still be copied away.