RE: Best CI for process

From: Sandy King ^lt;[email protected]>
Date: 10/03/05-05:36:32 PM Z
Message-id: <a06020429bf676fff7fe6@[192.168.2.2]>

Eric,

Send me the numbers and I will plot the curves. Also, send me the
actual transmission densities of the step wedge you used to make the
print if you have them.

I will pull out a recent palladium step wedge file and do the same for you.

As you suggest, the actual numbers would provide much better comparative data.

Best,

Sandy

>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 17:36:50 2005

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