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 16:53:25 2005