On 7 Mar 2005 02:10:07 -0800,
wrote:


Jean-David Beyer wrote:
LR Kalajainen wrote:
It takes at least 24 hours of soaking before the brighteners begin
to
wash out. In prints left in water overnight from, say, 11 pm until
8
am, the brighteners aren't affected--- at least I've not been able
to
tell any difference visually.

Brighteners begin to wash out right away, ...


Just as well. The sooner they wash out the better. I recall
reading that the brightener titanium dioxide contributes to
peroxide production with attendent image degradation.
think whiteners are more used with RC papers. To easy to
measure loss of whiteners for there to be any question. Dan

mar905 from Lloyd Erlick,

How long do the brighteners last? Given an ideally
processed print, whatever that might be, do the
brighteners have a lifespan? Will they last as long as
the print, or 'wear out' some time before the print
dies? Will the print become less acceptable at some
time during its life because the brighteners have
stopped working? If the print is otherwise in good
condition, but the brighteners are worn out, is the
print less acceptable? Must darkroom workers make
prints expected to be 'good' only as long as the
brighteners are present, presuming the brighteners stop
working at some time. Since the brighteners work only
under some amount of ultraviolet light, what about
those of us who display prints mostly under
incandescent light? Is there an ideal level of UV, and
an ideal type of UV, for print display? Do the paper
manufacturers specify that level?

Just curious.

regards,
--le
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