Re: Yellow pigment stain: (Was: Re: Sodium Bisulfite

gdimase@hotmail.com wrote:
>
> Same process, same paper, same pigment, same everything also same negative
> but the yellow pigment was applied before the cyanotype and NO stain.
> Any explanation?

Let me make sure I understand what you're saying; are you saying that in
one case you put the yellow on second, after the cyanotype, and got a
yellow pigment stain, and in the other case you put the yellow on first
and got no yellow pigment stain, and in both cases everything else was
the same? And does this mean that you know certainly that the amount of
pigment in relation to gum was the same in both cases, either by careful
measurement or by using the same mix in both cases?

Katharine

> Giovanni
>
> ----- Original Message -----
> Wrom: BGJSNBOHMKHJYFMYXOEAIJJPHSCRTNHGSWZIDREXC
> To: <alt-photo-process-l@sask.usask.ca>
> Sent: Tuesday, August 24, 2004 11:15 AM
> Subject: Re: Yellow pigment stain: (Was: Re: Sodium Bisulfite
>
> > gdimase@hotmail.com wrote:
> > >
> >
> > > pd Can you instruct me on "pigment stain"?
> >
> >
> > http://www.pacifier.com/~kthayer/html/stain.html
> >
> >
> > How can it happen when there is
> > > no light?
> >
> > Because pigment stain has nothing to do with light.
> >
> > Katharine Thayer
> >
> >
> >
> > My paper is Begger 300 gr. and my pigment manufacturer is
> > > "Maimeriblu".
> > >
> > > ----- Original Message -----
> > > Wrom: NNYCGPKYLEJGDGVCJVTLBXFGGMEPYOQKEDOTWFAOB
> > > To: <alt-photo-process-l@sask.usask.ca>
> > > Sent: Tuesday, August 24, 2004 6:17 AM
> > > Subject: Yellow pigment stain: (Was: Re: Sodium Bisulfite
> > >
> > > > gdimase@hotmail.com wrote:
> > > > >
> > > > > Hi Katharine,
> > > > > I assume the sodium bisulfite is on a 12% concentration.
> > > > > How much time you put the picture in the bath?
> > > > > An the you bath it again in a water bath, for how long?
> > > > > What about stubborn cases? You keep it longer?
> > > > > Let me give you a recent example of what happened to me:
> > > > > I was working on a full color print, this picture has an open clean
> > > white
> > > > > sky therefore the negative section of the sky is totally black.
> > > > > I did my first cyano print and everything was fine (sorry I sized
> the
> > > day
> > > > > before first with gelatin and glyoxal).
> > > > > I go next day for my Blue channel and yellow pigment and the sky
> comes
> > > out
> > > > > "yellow", I thought it was stained, next day I did my Green channel
> and
> > > > > magenta pigment and I got a beautiful picture but with the yellow
> sky
> > > (as I
> > > > > said out of a black negative).
> > > > > I wash it with sodium bisulfite and the stain is still there.
> > > > > Yes, I know I can create a new negative and paint the sky on white
> but I
> > > > > want to know what may have happened.
> > > >
> > > > Hello Giovanni,
> > > > That's almost certainly pigment stain, not dichromate stain--- a
> > > > different issue entirely. I don't mean to discourage you, but it may
> be
> > > > less frustrating for you in the long run to master monochrome printing
> > > > before attempting tricolor, at least that's the sequence many people
> > > > find most rewarding for gum printing.
> > > >
> > > > Yes, I suppose you could print opaque white over your stain, but I
> doubt
> > > > the result will be the same as the result you would get by printing in
> > > > color on white paper.
> > > >
> > > > Katharine Thayer
> > > >
> >
Received on Wed Aug 25 15:37:14 2004