[alt-photo] Re: dilution of pt/pd

[Terry King]

Loris


I have used different approaches. That is why I use the one that works.


The solarisation does happen when  one uses pt/pd. 


Loris.  There were no pure whites in the subject of the prints you mention. That is why there are none in the print. There are, however the delicate gradations of tone which I aimed for. You are making false assumptions that do not  make sense. You also seem to be applying a Procrustean bed to your prints. I feel tempted to say that they look  contrasty  but do you really think that it is wise to make such judgements from prints on a web site  or even in a book? One of the main points of platinum printing is that the tactility and other aspects of platinum prints cannot be appreciated unless one has held the original in one's hands.


What  do you mean  that I have difficulty keeping the DR of my negatives constant ?  The DR should NOT be constant from negative to negative, (see my comment on the Procrustean bed). The negative  should reflect the tones of the subject. Have you not found that the light varies from subject to subject ?  If the subject has a range of one stop, so should the negative. If the subject has a range of seven and a bit stops, so should the negative.  The print should, if one wishes, reflect those ranges. Isn't this variability one of the glories of platinum printing ? The method I have developed for making negatives for platinum printing enables a wide range of tone giving one the opportunity to achieve gradations in areas where you appear to expect pure whites. This has been explained in both View Camera and AG. I think your printing would benefit from using this method. I  run workshops.


If ignorance is bliss, why are not more people happy ?


All the best


Terry





-----Original Message-----
From: Loris Medici <mail at loris.medici.name>
To: The alternative photographic processes mailing list <alt-photo-process-list at lists.altphotolist.org>
Sent: Sat, 24 Jul 2010 14:56
Subject: [alt-photo] Re: dilution of pt/pd


Terry,

2010/7/24 Terry King <terryaking at aol.com>:
> ...
> In everyday practice of develop out platinum printing, using the dilutions I 
have already cited,  there is no difference between
> ammonium ferric oxalate and ferric oxalate.

(%) I would suggest that you practice more or to (at least) try
different practices then... (Epecially if you intend to talk about /
criticize them!)

> ...
> In fact for many years, as I had never experienced 'solarisation' with 
platinum printing using ferric oxalate, I wondered what people
> were talking about. What did make a difference was using  precious metal 
solutions that were too weak or papers which were highly
> buffered when there had been no pre-soak in oxalic acid..

Good for you. But, in fact, there are people who had experienced
this... BTW, IIRC, you weren't printing pure Pd - according to a
statement you've made a couple of days ago, therefore your point above
is kinda moot. (Because adding Pt into the coating solution
effectively inhibits this phenomenon...)

> ...
> As I have made ferric oxalate as an exercise on workshops from year to year, I 
can tell you from the evidence of having ferric oxalate
> of different vintages, that ferric oxalate in solution loses in speed by about 
a third of a stop a year.   Ferric oxalate, kept in brown
> bottles, as  much as five years old is still perfectly usable given the 
appropriate exposure.  I suggest that you correct your notes to
> take account of this evidence.

(*) I guess maybe your statement above explains why many of your
prints doesn't show pure whites (I mean where we expect them; e.g.
interior shot, strong daylight/backlight coming from windows, no
detail of the outside) in your (e.g.) Opera Regis -> Platinum gallery
(Church Interiors), whereas some do... (VERY IMPORTANT: I'm not saying
"we absolutely need pure whites and/or pure blacks in photographs",
though! - Please lets not start another pointless discussion from
here...) My guess would be: (a.) It's due to non-light induced /
premature reduction of Fe(III) to Fe(II) causing fog and/or (b.) You
have problems with keeping your negatives' DR constant. (With a little
/ reasonable play...) and/or (c.) Those reproductions are horrible.
(Or - at least - inconsistent.)

> ...
> It is easy to dissolve ferric oxalate, just keep it in a warm water bath and 
stir from time to time. There are simple tasks in cookery
> which are more complicated.

To me, your internal definition of "easy" is extremely variable /
volatile then...

> ...
> I calibrate my negatives and have had no problems with ferric oxalate using 
different sources of supply,( apart from having to add
> oxalic acid), and solutions made in class using different methods.

See the latter parts of the section marked with (*) above...

> ...
> There seems to be far too much 'research' to solve problems which do not 
exist. That has been true over the history of photography
> from 'The Silver Sunbeam' to Mike Ware.

Ignorance is bliss, indeed... (See the section marked with '%' above...)

Regards,
Loris.
_______________________________________________
Alt-photo-process-list | http://altphotolist.org/listinfo