>Philip Jackson said:
>Pete, I'd hesitate about recommending 1% sulphuric acid on
>a) health and safety grounds
>b) it performed only marginally better
>c) acids are bad news for paper
Terry
I have answered Philip in a separate e:mail, but what I do find rather
strange is your support for Philip's position on health and safety
grounds. I seem to remember you saying in reply to Peter Marshalls health
and safety comments in respect to the photogravure workshop I quote:-
>One has to bear in mind when working with responsible adults that they prefer
to take their own decisions on the basis of the facts; they do not like to be
nannied.
terry King<
We have a saying don't we Terry what is sauce for the goose is also sauce
for the gander !!
> that the sulphuric acid is likely to soften the paper and the image as HCl
does when used as a the clearing agent in platinum printing.<
And a twelve hour soak in London water does not I presume
> sulphuric acid,according to some authorities, will convert the gum to
dextrine<
Which authorities how and when ?
> if the exposure is adequate, there is no dichromate stain, and no need for
anything other than water to clear the dichromate <
There is always dichromate stain, but I agree the tests showed that all the
methods cleared in for all intents and purposes in a very similar manner
at normal exposures, the results were practically the same, However as you
have also said, recently. I quote:-
>There ain't one right way of doing it.
Terry King<
>Poitevin in the 1850s. who added pigment to the mixture. Ponton's examples do
not survive but Pouncy's still have vigour to the extent that they look better
after one hundred and forty years than modern gum prints I have seen hanging on
gallery walls.<
Your first comment Pontons work may not have survived but there could be
a number reasons for this I do not have the exact historical details so I
cannot
comment
Who is to say there is not a dichromated image underlying Pouncy's work. ?
cheers pete