From: Liam Lawless (liam.lawless@blueyonder.co.uk)
Date: 12/05/02-07:19:53 PM Z
Richard,
Note that KOL said Herschel developed the "dirty yellow image" with
ferrOcyanide. I thought it was probably a misprint, but maybe not.
Liam
-----Original Message-----
From: rurmonas@senet.com.au [mailto:rurmonas@senet.com.au]
Sent: 06 December 2002 11:24
To: alt-photo-process-l@sask.usask.ca
Subject: RE: VDB test results - part 1
Quoting rurmonas@senet.com.au:
> Oh great now we have opened a pandora's box. I tried putting a fixed VDB
> into thiourea toner (without bleaching step). As you said a colder tone
> and I noted better seperation of shaddow details. So tried a fixed
> VBD in alakali and acid with no obvious effect (this was this morning
> before work, so I did not have time to dry prints).
>
> In some recent cyanotype testing I noted that if paper is coated with
> just FAC (no ferricyanide) and exposed and washed there is a "dirty
> yellow" image formed. So tried this in acid, alkali, and fixer. It
> is not readily soluble in any of these. So it is possible that some
> iron can find its way into the final VDB image (after fixing etc. etc.).
> Tried this FAC image in the thiourea toner, but no effect. So this is
> not the direct cause, but still allows the possibility of iron compounds
> in the final image.
Forgot to mention that I tried putting ferricyanide on a VDB and on
the FAC image. Both showed no blue so they any iron is not in a form
which will readily produce prussian blue
I need more sleep !
Richard
--- Richard Urmonas rurmonas@senet.com.au ------------------------------------------------- This mail sent through SE Net Webmail http://webmail.senet.com.au
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