You said:
>.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.
Pete, I just quoted Philip's para and commented on the bits I was interested in.
Perhaps I should have deleted the H & S line from the quote. I agree that the
health and safety point is not a strong one in this discussion although my own
practice is to avoid the use of sulphuric acid as much as possible in workshops
as it is very vigorous in its action resulting in holes in clothes when they
come out of the washing machine and it even burns through the materials one
tries to wipe up spillages with. In fact I only use it now for making up the
sodium sulphite lye for acid amidol . I suppose one has to take decisions as
the qualities of individual members of a group before undertaking certain
processes, keeping the making of ferric oxalate, for example, to those times
when the over enthusiastic are not around. I am sure that you do too.
>We have a saying don't we Terry what is sauce for the goose is also sauce
>for the gander !!
I heartily agree.
>> 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
Certainly there is a distinct difference in sharpness between pl/pd prints
cleared in HCl and those cleared in EDTA even when they have both been washed
over night.
>> sulphuric acid,according to some authorities, will convert the gum to
dextrine<
>Which authorities how and when ?
I will try to find the reference.
> 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.
What I try to do however, is to use those means that do not invove me in
unnecessary work !!!
>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. ?
I do not know if there is or not but Pouncy used indian ink as his pigment
whch would hide any dichromate stain.
Is this a good time for the Essex marshes ?
Terry