[alt-photo] Re: Gum over cyanotype question

[Loris Medici]

Oops!!! My apologies to Marek and thanks again for the very useful tip! :)


On 29 Şub 2012, at 17:40, "C.Breukel at lumc.nl" <C.Breukel at lumc.nl> wrote:

> Loris,
>
> I think it was Marek actually, but I agree completely, this bleach back technique is very useful, I even used it on bullet proof Pyro negatives, tailored to Pt printing..
>
> Best,
>
> Cor
>
> Ps let me plug again a page I did make onit:
>
> http://members.casema.nl/cordieuwke/GumOverPlatinumII.html
>
>> -----Original Message-----
>> From: alt-photo-process-list-bounces at lists.altphotolist.org [mailto:alt-
>> photo-process-list-bounces at lists.altphotolist.org] On Behalf Of Loris
>> Medici
>> Sent: woensdag 29 februari 2012 16:28
>> To: The alternative photographic processes mailing list
>> Subject: [alt-photo] Re: Gum over cyanotype question
>>
>> For the records / reminder for everybody:
>>
>> There's a very nice way of doing one coat gums with "convincing
>> blacks"; mixing a highly pigmented gum emulsion rich of dichromate and
>> giving it a hard exposure then developing in very mild bleach
>> solution. (Or you just give a kick-start to the development in bleach
>> solution and then continue in water...) It works like a charm! I think
>> it was (again) Alberto who coined this few years ago, but I maybe
>> confusing the person. Another **very useful** trick I have learnt
>> here!!! :)
>>
>> Regards,
>> Loris.
>>
>>
>> 29 Şubat 2012 16:38 tarihinde Christina Anderson <zphoto at montana.net>
>> yazdı:
>>> ...
>>> Interesting you have not found prolonged exposure necessary with black.
>> My guess is your black layer is thinner/less opaque than mine. An old
>> pictorialist tradition was to use a thick gum/highly pigmented black layer
>> with super long exposure and then good development to get one-coat gums. I
>> find the trick is to use enough black for density but not too much because
>> flaking occurs. I have not yet mastered this, though...on my list of
>> things to do. With the one coat--no sizing, no shrinking, and if I
>> remember Buxton/Ashton Platinum was the recommended paper when this
>> discussion was going on.
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