RE: Best CI for process

From: Eric Neilsen ^lt;[email protected]>
Date: 10/03/05-05:26:41 PM Z
Message-id: <20051003232643.D2C6876EAF@spamf4.usask.ca>

I don't know about apples to meatloaf, but.. You are right, monitor to
memory as my hard copies are at the sudio. However in a perfect world it
would be somewhat close from scanner to screen. That is why I suggested
numbers. I see that your Kallitype steps look close to your stated ES. I can
send you an excel sheet that I have my real numbers for reflected density. I
the long toe can be useable and perhaps that is why is it better to work
with real numbers of Dmax, and Dmin rather than interpret a "useful" or
subjective Dmax to 90%.

Have nice night

EJ

Eric Neilsen Photography
4101 Commerce Street, Suite 9
Dallas, TX 75226
214-827-8301
http://ericneilsenphotography.com
> -----Original Message-----
> From: Sandy King [mailto:sanking@clemson.edu]
> Sent: Monday, October 03, 2005 5:40 PM
> To: alt-photo-process-l@sask.usask.ca
> Subject: RE: Best CI for process
>
> Well, this is not an apples to apples comparison, now is it?
> Comparing a step tablet you are holding in your hand with an
> image on
> a monitor is more like apples to meatloaf. The image on the
> monitor
> may seem to show Dmax at Step 7, and that may be where I chose
> to
> place it, but in fact there is visual separation on the step
> wedges
> themselves all the way from about Step 1 or 2 to Step 7. So if
> am
> counting the way you count I would add at least five or six
> steps to
> the exposure scale.
>
> In theory one would like to establish Dmax as the first maximum
> black
> that merges with the next black on the step wedge, but as you
> well
> know, there is really no way to do that with Pt./Pd. because
> with its
> long toe until you get up to about 99% of maximum possible Dmax
> there
> will be both visual and measurable separation between the
> steps.
> Clearly, you have simply chosen to establish your speed point
> at a
> much higher% of Dmax than I do, and that is the reason for
> different
> ES values we have reported.
>
> Sandy
>
>
>
>
>
>
>
>
>
> >Well, that wasn't so hard. When I go to the unblinking eye
> site where you
> >show your pt/pd test, I see dmax at step 7 and and dmin and
> step 18 ,
> >showing 12 steps with an ES of 1.8. Step 1,2,3 were all of
> the same
> >density? And paper white is at step 19?
> >
> >
> >If, so that is not where I am counting. Steps 1 and 2 still
> show separation
> >and step 21 is darker paper white in my ES.
> >
> >
> >Eric Neilsen Photography
> >4101 Commerce Street
> >Suite 9
> >Dallas, TX 75226
> >http://e.neilsen.home.att.net
> >http://ericneilsenphotography.com
> >
> >> -----Original Message-----
> >> From: Sandy King [mailto:sanking@clemson.edu]
> >> Sent: Monday, October 03, 2005 4:49 PM
> >> To: alt-photo-process-l@sask.usask.ca
> >> Subject: RE: Best CI for process
> >>
> >> Eric,
> >>
> >> By intelligent I mean the ability to talk apples to apples.
> >>
> >> We have not been doing that, and based on your description
> of how you
> >> count the steps of a step wedge I now understand why. If I
> were
> >> counting everything but absolute Dmax I too would be
> reporting am ES
> >> of 2.4 or above.
> >>
> >> Sandy
> >>
> >>
> >>
> >>
> >>
> >>
> >>
> >>
> >>
> >> >Sandy, If by intelligent you mean that we all need to
> agree that there
> >> are
> >> >not absolute places to start to evaluate a curve, or
> straight line? There
> >> >are not absolute places. There are points of absolute
> density. ES and CI
> >> are
> >> >based upon interpretation of useful information that can
> be arbitrarily
> >> >applied.
> >> >
> >> >
> >> >If you are only printing 12 steps on a 21 step scale, one
> that has
> >> densities
> >> >range from 0.0 to 3.0, with step 1 and 2 blending and you
> are only
> >> getting
> >> >to step 13 before paper white with pure palladium, then
> our processes are
> >> as
> >> >different in capabilities as to be creating confusion.
> >> >
> >> >
> >> >
> >> >
> >> >
> >> >Eric Neilsen Photography
> >> >4101 Commerce Street
> >> >Suite 9
> >> >Dallas, TX 75226
> >> >http://e.neilsen.home.att.net
> >> >http://ericneilsenphotography.com
> >> >
> >> >
> >> >> -----Original Message-----
> >> >> From: Sandy King [mailto:sanking@clemson.edu]
> >> >> Sent: Monday, October 03, 2005 4:11 PM
> >> >> To: alt-photo-process-l@sask.usask.ca
> >> >> Subject: RE: Best CI for process
> >> >>
> >> >> Clay,
> >> >>
> >> >> I do indeed use a figure of 90% black when plotting
> with the
> >> >> Winplotter program. This gives very close to the same
> value as when
> >> >> measuring a step wedge print in the way I just
> described to Mark,
> >> >> i.e. from the first step about pure paper white to the
> first shadow
> >> >> step that merges visually with the next one.
> >> >>
> >> >> What I have been trying to figure out from the
> beginning of this
> >> >> thread is is, 1) are Eric and Emille using options
> which give a much
> >> >> longer ES than I am used to in my work, or 2) are we
> simply using
> >> >> terminology and practice that does not allow us to
> communicate
> >> >> intelligently on the subject?
> >> >>
> >> >> I still have not figured out which is the case, though
> some of the
> >> >> recent communications are making me lean toward the
> second of the two
> >> >> possibilities.
> >> >>
> >> >> Sandy
> > > >>
> >> >>
> >> >>
> >> >>
> >> >>
> >> >>
> >> >> >Is this exposure scale derived by counting 21-step
> Stouffer tables
> >> >> discernable
> >> >> >steps and multiplying by .15? The reason I ask is that
> I'm betting
> >> Sandy
> >> >> is
> >> >> >using the BTZS plotter program, and the way it
> calculates exposure
> >> scale
> >> >> is
> >> >> >predicated on picking a maxium black value. I know
> that Dick Arentz
> >> uses
> >> >> 90%
> >> >> >black for his work....
> >> >> >
> >> >> >Quoting Eric Neilsen <e.neilsen@worldnet.att.net>:
> >> >> >
> >> >> >> Sandy, I don't use or test a pure palladium. The
> smallest amount
> >> of
> >> >> platinum
> >> >> >> that I add is 15% of total metal salt solution. I
> make my own
> >> ferric
> >> >> oxalate
> >> >> >> and use a palladium solution that is mixed at 5 g
> NaPd with 3.5g
> >> NaCl
> >> >> to
> >> >> >> make 40 ml. This makes a .7 M solution to match my
> .7 M ferric
> >> >> oxalate. The
> >> >> >> Platinum is a .457M solution in potassium version
> and .7M when I
> >> can
> >> >> get the
> >> >> >> ammonium version. The molarity may be off by +/-
> .015 as these are
> >> >> from
> >> >> >> memory but I don't think so.
> >> >> >>
> >> >> >> My exposure scale for the 1.0ml FO, .15ml K Pt, and
> .85ml Na Pd,
> >> is
> >> >> 2.45.
> >> >> >>
> >> >> >> I make most of my exposures after a 10 minute dry@
> 100F and a 30
> >> >> minute
> >> >> >> humidification @60% RH. I process in Potassium
> Oxalate at both
> >> room
> >> >> temp of
> >> >> >> 70 and heated to 90F. The exposure test that
> produced the ES above
> >> was
> >> >> >> processed at 70F.
> >> >> >>
> >> >> >> These test were also performed with Starphire glass
> in the
> >> contacting
> >> >> >> printing frame.
> >> >> >>
> >> >> >>
> >> >> >>
> >> >> >>
> >> >> >> Eric Neilsen Photography
> >> >> >> 4101 Commerce Street, Suite 9
> >> >> >> Dallas, TX 75226
> >> >> >> 214-827-8301
> >> >> >>
> >> >> >>
Received on Mon Oct 3 17:27:08 2005

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