In message , Martin
writes
I thought the problem is not the printing ink/toner, but, rather, the
(chlorine?) bleach used to make the paper white? Book publishers
(especially US) also often identify the paper used as being 'acid-free',
but what about other paper?

Book publishers identify paper as acid free to indicate that the paper
doesn't self destruct in the way that non acid free paper does.
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Ah ... and here I thought it was environmentally friendly somehow...
(good news for paperbacks I'm fond of, though)

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Klara, Gatwick basin