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

From: Judy Seigel ^lt;>
Date: 08/24/04-11:35:32 PM Z
Message-id: <>

On Tue, 24 Aug 2004 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?
> Giovanni

Pigment stain has many variables.

Such as -- I haven't been following this closely enough to be sure, but it
sounds above as if the yellow was the first coat. If so, possible roughing
up of the paper, either from scrubbing pigment on or development brushing
could have happened... If the paper had a size coat that wasn't
adequately hardened, one of the symptoms is pigment stain. Then the
subsequent coats could "tan" that gelatin, so staining would cease.

Another possibility is that your yellow is simply a stainer. Some pigments
or additives (for example dispersal agents), which a manufacturer might
put in some, not others, cause pigment stain. Did you try this paint on
its own?

Another point, for what it's worth, many papers will give a free ride for
one coat without a size... the surface size left from the manufacturer
prevents pigment stain. Then the first development not only washes off the
surface size, it raises the nap of the paper, so it holds more pigment.

And so forth. Your question in other words is not as simple as it sounds.
But, all other things being equal (ie, good size, hardened properly,
etc.), I'd suggest testing the yellow.

Received on Tue Aug 24 23:35:59 2004

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