"john hamilton" writes:
After reading our newspapers we end up with an oily dirt on our hands, but
not after reading the magazine supplements that come inside the newspapers
or the television guide magazines.

Even were the printing processes identical for newspapers and the magazines,
you would still find a marked difference in the extent their pages soil your
fingers during handling. Most newspapers still use an oil-based ink, the oil
being a slow-drying hydrocarbon solvent, and it takes days to evaporate.
For the articles in newspapers to be current, they are usually printed on the
morning that you read them, meaning their ink has not had a chance to dry.
The supplements, on the other hand, are printed days ahead and the solvent
in their ink has had plenty of time to dry (almost).

Historically, inks have contained traces of toxic substances, especially the
coloured inks, and I expect that in some countries that is still the case.
But here in Australia, I have not heard anyone caution against the use of
newpapers or magazines for gardens and composting. Presumably, the industry
here is regulated to use only non-toxic inks. (The same does not apply to
dyes in inks and cosmetics imported from China.)

The search for a more environmentally-friendly printers ink has been a topic
of much discussion over the years in our local daily, where invariably the
response has been that available water-based inks still have one or more
shortcomings in comparison with the traditional oil-based product. Only
recently was it announced that an acceptable substitute has been developed.

I don't know whether it's the ink, or the fibrous paper itself, which gives
newspaper its recognised capacity to shine window panes and mirrors. Guess
I could discover for myself by tearing off a handful of unprinted sheet
borders and trying to polish a mirror with them. :-)

Would anyone know how to explain simply how the method of printing is done
differently between the magazines and the newspapers? Thanks for any
advice.

I can't address that as I don't know. Maybe someone else can or already has?

Because our fingers (i.e., our skin) secrete both natural oils and also water
(perspiration), we tend to get stained by dyes which are soluble in oil (i.e.
the stuff from 'permanent' markers) and also by dyes which are soluble in
water. The best (or worst) of both worlds, as it were.
--
John Savage (my news address is not valid for email)