[Alt-photo] suggestions about cyanotype curve

Bob Cornelis bob at colorfolio.com
Fri May 26 20:05:25 UTC 2017


Francis

Yes! I've made this mistake as well. One has to really do these things in
the correct order. I've even written a photoshop action script to make sure
of that.

Thanks for the pointer.

Bob


On Fri, May 26, 2017 at 11:58 AM, francis schanberger via
Alt-photo-process-list <alt-photo-process-list at lists.altphotolist.org>
wrote:

> How can I put this delicately?
>
> If this works with the digital negative work flow you are using, make sure
> that you flatten your image with the curve prior to inverting the image to
> a negative. It may not be the cause of your tonal range grief but I have
> made this mistake, students have done it and I have even seen a colleague
> at my school get stumped by the inverted curve error.
>
> -francis
>
>
>
> On Thu, May 25, 2017 at 1:13 PM, Christian Nze via Alt-photo-process-list <
> alt-photo-process-list at lists.altphotolist.org> wrote:
>
> > Less ink
> >
> > Le 22 mai 2017 20:50, "Don via Alt-photo-process-list" <
> > alt-photo-process-list at lists.altphotolist.org> a écrit :
> > >
> > > Sounds like you have too much UV blocking with your digital negative.
> > >
> > > Have you printed a regular analog step tablet to determine the contrast
> > > range of your process?
> > >
> > > Just a thought.
> > >
> > > Don Bryant
> > >
> > > -----Original Message-----
> > > From: Alt-photo-process-list
> > > [mailto:alt-photo-process-list-bounces at lists.altphotolist.org] On
> Behalf
> > Of
> > > Bob Cornelis via Alt-photo-process-list
> > > Sent: Monday, May 22, 2017 1:25 PM
> > > To: alt-photo-process-list at lists.altphotolist.org
> > > Cc: Bob Cornelis
> > > Subject: Re: [Alt-photo] suggestions about cyanotype curve
> > >
> > > Hi Peter
> > >
> > > Thanks for the suggestion. I think, however, that my problem is not
> lack
> > of
> > > contrast but, rather, too much contrast, at least in the highlights.
> The
> > > rest of the tonal range, all the way down to the shadows are behaving
> > > properly.
> > >
> > > Regards
> > > Bob
> > >
> > >
> > > On Mon, May 22, 2017 at 10:10 AM, Peter Friedrichsen via
> > > Alt-photo-process-list <alt-photo-process-list at lists.altphotolist.org>
> > > wrote:
> > >
> > > > Bob,
> > > > Without seeing your samples, I can suggest one possibility; a thick
> > > > coating of the sensitizer. I have found that contrast increases, the
> > more
> > > > one applies to the paper. It may be due to the uv blocking effect
> such
> > > that
> > > > the sensitizer that is bound to the paper never gets a chance of
> > exposure
> > > > in the shadow areas due to the filtering effect of the sensitizer
> > sitting
> > > > overtop. Whatever the reason, that is my observation. I know others
> > will
> > > >  suggest other possible causes.
> > > >
> > > > Peter Friedrichsen
> > > >
> > > > > On May 22, 2017, at 11:04 AM, Bob Cornelis via
> Alt-photo-process-list
> > <
> > > > alt-photo-process-list at lists.altphotolist.org> wrote:
> > > > >
> > > > > Hi All
> > > > >
> > > > > I'm looking for a little help finishing a custom curve I've made
> for
> > > Ware
> > > > > cyanotype printing using Peter Mrhar's method from Easy Digital
> > > > Negatives.
> > > > >
> > > > > I'm having problems getting a smooth gradient from steps 0-10. Pure
> > > white
> > > > > is step 0, pure black step 100. My tones from steps 10-100 are
> pretty
> > > > > linear, but within the highlights I've got about half the steps
> pure
> > > > white
> > > > > and then there is a steep jump to a value of close to 10. I'd like
> to
> > > > find
> > > > > a way to get a smooth gradient in this part of the tonal range.
> > > > >
> > > > > Without a curve, all steps from 0-14 are pure white so the curve
> has
> > to
> > > > do
> > > > > a lot of work to introduce a gradient in a relatively small portion
> > of
> > > > the
> > > > > curve range. I've tried tweaking with the curve in that range by
> hand
> > > but
> > > > > without success.
> > > > >
> > > > > I was wondering if there are other tricks people know of to handle
> > this
> > > > > type of situation, either chemically, through exposure,
> development,
> > > etc.
> > > > >
> > > > > My first wash is in 3% citric acid for a couple of minutes, 20 sec
> in
> > > > > peroxide solution, then about 25 min in water.
> > > > >
> > > > > I've attached 3 screenshots for anyone interested showing my
> > pre-curve
> > > > and
> > > > > post-curve step wedges (100 steps), and the curve itself (note it
> is
> > a
> > > > > pre-inversion curve).
> > > > >
> > > > > Thanks!
> > > > > Bob
> > > > >
> > > > >
> > > > > --
> > > > >
> > > > > http://www.bobcornelis.com
> > > > > _______________________________________________
> > > > > Alt-photo-process-list | altphotolist.org
> > > > _______________________________________________
> > > > Alt-photo-process-list | altphotolist.org
> > > >
> > >
> > >
> > >
> > > --
> > >
> > > Color Folio
> > > www.colorfolio.com
> > >
> > > 2550 Lewis Dr.
> > > Sebastopol, CA 95472
> > > 707.824.8910 <(707)%20824-8910>
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> > >
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> > > Alt-photo-process-list | altphotolist.org
> > _______________________________________________
> > Alt-photo-process-list | altphotolist.org
> >
>
>
>
> --
> francis schanberger
>
> www.francisschanberger.com
> _______________________________________________
> Alt-photo-process-list | altphotolist.org
>



-- 

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