Re: gum neg


Julian Smart (planetzed@btinternet.com)
Sat, 08 May 1999 00:07:40 +0100


----------
> From: Judy Seigel <jseigel@panix.com>
> To: alt-photo-process-l@sask.usask.ca
> Subject: Re: gum neg
> Date: 07 May 1999 21:34
>
>
>
> On Fri, 7 May 1999, Julian Smart wrote:
> > shorter exposures for the shadows, but of all the prints I've done over
the
> > last few months,this is the only one that won't clear without lots of
very
> > delicate brushwork.
>
>
> "Clearing" in my experience is related to many factors besides the
> negative. Did anything else change? Sometimes certain pigments, for
> instance, or pigments with a certain gum, or one or the other with a
> particular paper/size combination, is the culprit.
>
> Usually (tho not always), a negative will "clear" if it's developed long
> enough... how long was your soak in this one?
>
> Judy
>

Judy,

The picture has been printed three times,all the same pigments and sizing
methods.twice from the same 10*8 FP4 neg.(Fabriano 5 Satine and Fab.
Artistico) and once from a 16*12 paper neg.
produced from a 5*4 FP4 interpos (Fab. Artistico). The Satine has beter
fine detail owing to lack of paper texture, the Artistico (off white) has a
canvass texture but better sharpness.
I don't have densitometer readings to relate (Demarchy and Puyot never had
them...... etc!!) so can't accurately give you a dr. but the two negs LOOK
very similar, even to a trained eye. The film neg needs 1min 15 secs. for
the highlight coat and (four coats later) 30 secs for the shadow density. A
soak of 24 hours on either the first or last coats will not clear the
highlights to white from either neg- hence my saying that as the entire
tonal range of the
scene falls along the straight line portion of the char.curve, there is
nothing outside either range to produce pure white or a maximum density
other than was in the original scene. There is no dichromate or pigment
staining. I feel the real problem with the print could be either my coating
method not being subtle enough, or the wrong dilution/concentration of
dichromate(maybe the proportion of dichro. in the emulsion mix). I am now
starting to experiment with altering the proportions for the various
layers.
The paper neg, unfortunately, behaves exactly the same way as the film
neg.- the exposures being elevated accordingly. I feel I have already
produced what I wanted from the neg and am happy with what I've got. It
just seemed to be an anomoly- though nonetheless challenging.

Julian.



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