Re: Best CI for process

From: Clay ^lt;[email protected]>
Date: 10/03/05-07:18:24 PM Z
Message-id: <22F589D2-C7BF-4305-8898-4261EFA44AAC@wt.net>

Just to add some fuel to the fire, I think there are sometimes subtle
differences between papers that will allow a worker to use more of
the dense (dark) parts of the print curves. In my work, I find that
Rives BFK, for whatever reason, seems to have more open, contrasty
shadows than most of the other papers I use. So if an image relies on
shadow detail, then that is usually a good choice. Other papers,
although they may give great Dmaxes, seem to have muddled shadow
separation. This is something that is purely visual, and I have never
been able to measure these differences reliably with a densitomer.
Yet it is real. I have done blind tests showing people the same print
made with two papers, and they invariably prefer the one with the
most shadow 'pop'. I think when it comes to subtlety, the eye will
trump the machine any day.

Just a side note about the Rives - it is difficult to clear properly.
I usually have to resort to one of the stronger acids for at least
one of the clearing baths to get this paper completely cleared.

This whole discussion reminds me of the many crude jokes told in high
school locker rooms, all of which have the punch line: 'It depends on
where you start measuring'

Clay

On Oct 3, 2005, at 8:03 PM, Sandy King wrote:

> 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 19:19:01 2005

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