RE: Best CI for process

From: Sandy King ^lt;[email protected]>
Date: 10/03/05-07:03:19 PM Z
Message-id: <a0602042abf678333003a@[192.168.2.2]>

Eric,

Here are my step wedge values for a straight palladium print, i.e. no
platinum or Na2, developed in potassium oxalate, 1ml of a 5%
dichromate solution added per liter of developer. The Stouffer TP45
step wedge was exposed for four minutes with a bank of BLB
fluorescent tubes, at about 4" from the printing frame.

When I plot the numbers I get an ES of 1.90, with IDMax set to 90%.
If I set the IDMax to 100% of black I get an ES of 2.40. Same data,
only that one change.

Let me know if you have any questions.

Step # log density
1 1.51
2. 1.49
3. 1.47
4. 1.37
5. 1.26
6 1.11
7. .97
8 .85
9. .71
10. .58
11. .47
12. .37
13. .29
15. .18
16. .15
17. .12
18. .10
19. .09
20. .08
21. .07

I have a very long day tomorrow so won't be able to look at your data
until tomorrow evening.

I have some tests that show slightly less and slightly more ES, and
some that show slightly less and slightly more Dmax, but this is a
very typical one for my work.

Sandy

>Joe, if you have seen Dick's book, he does go into it all quite in depth.
>But he does choose to set his black at the 90 % Sandy mentions. This 90% is
>straight from Phil Davis and Beyond the Zone system. I don't know if it
>really that relative to the platinum process. But As you can see, Sandy and
>I will work in some real step wedge, print density numbers. I can evaluate
>somewhat better from those and he will from mine.
>
>Dick's underlying chemistry is not the same as mine so things may be more
>than just a matter of semantics.
>
>Eric Neilsen Photography
>4101 Commerce Street
>Suite 9
>Dallas, TX 75226
>http://e.neilsen.home.att.net
>http://ericneilsenphotography.com
>
>> -----Original Message-----
>> From: Joe Smigiel [mailto:jsmigiel@kvcc.edu]
>> Sent: Monday, October 03, 2005 5:57 PM
>> To: alt-photo-process-l@sask.usask.ca
>> Subject: RE: Best CI for process
>>
>> Eric and Sandy, et.al.,
>>
>> I'd just like to comment that this is very confusing to a bystander.
>> For example, the post below implies steps 1-7 all have the same density,
>> i.e., "dmax", and yet the question asks if only "step(s) 1,2,3, were all
>> of the same density?" Reading this stuff it sounds like there is an
>> arbitrary dmax and then a different absolute dmax. Is there?
>>
>> Is there an ISO standard for reporting dmin, dmax, and density range?
>> If so, can you point to a good source that would explain it (maybe Phil
>> Davis BTZS or...)?
>>
>> Could this just be simplified to a statement such as: only steps 7-19
>> are separated on the print. This certainly implies that shadows at
>> steps 7 and below are blocked and the same tone (dmax), and that paper
>> white occurs at step 19 with the remainder blocked and printing white
>> also. By extension, 12 steps have printed as separated values giving a
>> density range of 1.80, or would/should you count 13 distinct steps on
>> the paper and a range of 1.95? There has to be a standardized, simpler,
>> less ambiguous way of reporting these results.
>>
>>
>> Joe
>>
>> >>> e.neilsen@worldnet.att.net 10/03/05 6:08 PM >>>
>> 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 19:03:38 2005

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