[Alt-photo] Digital negatives help?

Don Bryant donsbryant at gmail.com
Wed Sep 28 21:16:15 UTC 2016


Absoulutely. I mainly use the Stoufers to monitor the process. Digital step
tablets aren't consistent, the Stouffers is.

On Sep 28, 2016 5:07 PM, "johnbrewerphotography--- via
Alt-photo-process-list" <alt-photo-process-list at lists.altphotolist.org>
wrote:

> While I do use a Stouffer can't you just do a test strip with neg
> substrate overlapping a sensitised area on paper looking for where the two
> areas are the same dmax Don? Or am I missing something?
>
> Sent from my iPhone
>
> > On 28 Sep 2016, at 10:01 pm, Don via Alt-photo-process-list <
> alt-photo-process-list at lists.altphotolist.org> wrote:
> >
> > How did you establish your Standard Printing Time?
> >
> > -----Original Message-----
> > From: Alt-photo-process-list
> > [mailto:alt-photo-process-list-bounces at lists.altphotolist.org] On
> Behalf Of
> > Niranjan Patel via Alt-photo-process-list
> > Sent: Wednesday, September 28, 2016 3:48 PM
> > To: alt-photo-process-list at lists.altphotolist.org
> > Cc: Niranjan Patel
> > Subject: Re: [Alt-photo] Digital negatives help?
> >
> > Don:
> >
> > OK, let me show the method behind my madness.
> >
> > Please click the link and use altalt as a password to get in the page
> where
> > I have added two jpegs illustrating my procedure.
> >
> > http://niranjanpatel.zenfolio.com/p596379492#h1ede1c3b
> >
> >
> > After developing my initial process based on the composite black on
> B9180, I
> > set out to do the colorizing negative in search of higher UV opacity
> needed
> > to bump up the white point of the prints.  For that I eliminated the
> Blue as
> > a variable which is probably a safe choice, so I don't have to work in
> the
> > 3D.  Then I varied R and G from 0% to 100% with step size of 10% (that
> > translates to 25-26 in RGB points) to come up an 11x11 matrix that is
> shown
> > on Figure 1.  The grid lines were made with pure black (0/0/0) so the
> > comparison of under-performance and over-performance can be visibly made.
> > The square on the top right corner is also 0/0/0.
> >
> > Figure 2 is the resulting scan of the print.  It can be immediately seen
> > where the best cluster of squares is.  I picked the square, marked by a
> > circle, corresponding to the 51/128/0 in the negative as the best
> candidate
> > based on both the numbers as well as the fact that as one moved away from
> > it, the squares became significantly noisier, even when the readings were
> > comparable.  (I have noticed that the print from a colorized negative has
> > more noise than from a straight one, particularly in the mid to darker
> tones
> > for which I am working on a solution to - a subject for discussion at
> > perhaps an another time.)
> >
> > Next I took 51/128/0 as my center and created another checker board,
> varying
> > R and G in smaller steps of 2% (equivalent to 5 in RGB points.)  Figure
> 3 is
> > the result of that.  After printing and scanning, as seen on Figure 4,
> the
> > results point to a new center of gravity for opacity which is at
> 61/118/0,
> > albeit the improvement is modest - from 223 of 51/128/0 (marked by a
> circle)
> > to 227 of 61/118/0 (marked by a square.)  We are really splitting hairs
> > here, but the difference is real.  It was encouraging that although I did
> > both of these a a few days apart, the results were consistent.
> >
> > Now about the additional black layer as per your suggestion:
> >
> >>>>>
> > You can easily test this quickly by producing a
> > series of digital step tablets with progressive opacities (of the black
> > layer) printing them all on a single sheet of OHP
> > <<<<
> >
> > You really don't have to do the step wedge, only a block of 0/0/0 (before
> > colorizing) in order to simplify the process.  So if I take that 0/0/0
> block
> > and colorize with my old green shade of 51/128/0 and put the Black layer
> on
> > Multiply and vary the opacity.  "Blending if" options at this point do
> not
> > matter.  Here is what happens to the final values:
> >
> > Black Layer Opacity -  Final R/G/B values
> >
> > 0% - 51/128/01% - 51/127/03% - 50/125/05% - 49/124/0 7% - 49/122/010% -
> > 47/119/0
> >
> > All of these values are in the matrix of Figure 3, within 2 or 3
> points.  I
> > have marked the 5% point as A and 10% point as B to illustrate.
> >
> >
> >>>>>
> > So are you going to start printing salt after you run out of POP?
> >
> > <<<<
> >
> > I have a lb of Silver Nitrate sitting in my fridge for about the same
> time
> > as the POPs (hopefully it is still good) that says I ought to.  Also have
> > some Pt/Pd chemistry that I may want to do some printing with.  May be
> > before salt.
> >
> > :Niranjan.
> >
> > http://niranjanpatel.zenfolio.com/
> >
> >
> >
> >
> > From: Don via Alt-photo-process-list
> > <alt-photo-process-list at lists.altphotolist.org>
> > To: alt-photo-process-list at lists.altphotolist.org
> > Cc: Don <donsbryant at gmail.com>
> > Sent: Tuesday, September 27, 2016 5:12 PM
> > Subject: Re: [Alt-photo] Digital negatives help?
> >
> > Niranjan,
> >>
> > 4.  I use AdobeRGB 16-bit color space in Photoshop as well as in the
> > scanner.  Printing is done at HP's "Maximum DPI" from 1200 dpi files.
> > My question was buried at the end of my long-winded backgrounder in
> > yesterday's post.  In any case, I think I have the answer to that one
> now.
> >>
> >
> > I grok a lot of what you are describing, but I question your
> methodology. If
> > your blocking color is R=51, G = 128 then I would think you still have
> head
> > room to extend the UV density of your digital negative using that
> greenish
> > color path. However if you wish to use a black ink layer to target the
> steps
> > or part of the adjustment curve it should be very simple to do with the
> > Blend If method I listed for Henry.
> >
> > IME, doing that makes the negative get very dense quickly. At the time I
> was
> > testing this method, I was producing VDB and kalitype negatives and found
> > that the opacity of the black only layer needed to be set to a very low
> > amount - like about 5%. You can easily test this quickly by producing a
> > series of digital step tablets with progressive opacities (of the black
> > layer) printing them all on a single sheet of OHP. I flatten all of the
> > layers before printing and use the Text tool to label each giving me a
> > record to keep in my testing files. That way you can hone the required
> value
> > with one or two sheets of paper. For those two processes a black ink
> really
> > isn't needed when printing with Epson OEM pigmented inks.
> >
> > So are you going to start printing salt after you run out of POP?
> >
> > Don Bryant
> >
> >
> >
> >
> >
> >
> >
> >
> > _______________________________________________
> > Alt-photo-process-list | altphotolist.org
> >
> > _______________________________________________
> > Alt-photo-process-list | altphotolist.org
> _______________________________________________
> Alt-photo-process-list | altphotolist.org
>


More information about the Alt-photo-process-list mailing list