RE: palladium drydown and developer

For silver-gelatin prints, I use subtraction of exposure. For example,
if I get perfect test strip at exposure time of t seconds, I use 0.9t
seconds for the final prints. If the final print is to be toned in
polysulfide or polysulfide plus selenium, I may further cut the exposure
time, as these toners can darken the image a day after drying the print.

The factor above (0.9) is not far from what's used in reality, but some
paper requires smaller factor than others.

Also, using a dim viewing light in darkroom is important to prevent
prints that look too dark in real life situation.

Ryuji

On Fri, 21 Jul 2006 08:11:38 -0300, "BOB KISS" <bobkiss@caribsurf.com>
said:
> Hi all,
> It seems that there are some techniques for minimizing dry down and the
> discussion of the causes is very interesting but I feel, if you've got
> it,
> how do you live with it? Though I appreciate the commercial lab's
> techniques, I use a microwave oven (which I learned reading Ansel in the
> 80s). Used, they are pretty cheap and work very well for drying test
> strips. I lay the strip across the print in such a way to include the
> important highlight, midtone and shadow, when possible. I carry it
> through
> the process to about half way through the clearing, give it a 5 minute
> wash
> and then microwave it for two or three minutes in one minute steps,
> depending on the size of the strip. Voila! A dried down print. I judge
> my
> densities and choose my exposure accordingly. This has proved to be
> VERY
> reliable and I hardly ever have a print that isn't the density I have
> chosen. Whether I have chosen well is another question ;-)) but I get
> what
> I asked for!
> I mentioned in a post about 1 1/2 to two years ago that I found that prints
> from digital negatives had a curious drying phenomenon that prints from
> camera original negs did not. In prints from digital negs, the shadows
> lost
> density but so did the highlights...they both got lighter!!! In prints
> from
> camera original negs the dry down was more standard, i.e. the highlights
> got
> darker and the shadows lighter.
> CHEERS!
> BOB
>
> Please check my website: http://www.bobkiss.com/
>
> "Live as if you are going to die tomorrow. Learn as if you are going to
> live forever". Mahatma Gandhi
>
> -----Original Message-----
> From: Loris Medici [mailto:mail@loris.medici.name]
> Sent: Friday, July 21, 2006 7:48 AM
> To: alt-photo-process-l@usask.ca
> Subject: RE: palladium drydown and developer
>
> Hi Clay,
>
> My take / understanding is: when you coat the paper with some kind of
> reflective medium (gelatine, gum, wax and polyurethane wood finish as I
> do),
> the reason of the darkening and contrast increse in the shadows is caused
> by
> the fact that the higher refractive index of the coat causes some of the
> refracting light stay in the layer... Think of the mirror effect water
> causes when the light hits it surface from beneath with angles lower than
> xx
> (was it 38? - don't remember exactly - whatever you understand what I
> mean).
> Since less light is reflected back (and kept in the coating), density
> increases.
>
> Maybe your theory with fibers is also effective in this phenomenon but I
> think the actual/main reason/cause of the dmax increase is what I
> describe
> above.
>
> Regards,
> Loris.
>
> -----Original Message-----
> From: Clay [mailto:wcharmon@wt.net]
> Sent: 21 Temmuz 2006 Cuma 13:51
> To: alt-photo-process-l@usask.ca
> Subject: Re: palladium drydown and developer
>
> ...
>
> The other phenomenon that has not been mentioned is the microscopic
> 'fuzzing' of the paper surface that occurs as paper dries. This seems to
> affect the dark shadow areas much more. It is really more accurately
> called
> 'dry-up'. If you slap a wet pt/pd print on a reflection densitometer, you
> will get a much higher reading (in the
> 1.8 range) than you will a few hours later after it has dried. The tiny
> fibers of the paper then stand proud and cause a loss of reflection
> density
> that in the best of cases will give you reflection densities in the
> neighborhood of 1.4-1.5. This is almost a full stop of reflection density
> loss.
>
> As to what can be done to mitigate this effect, I have found that very
> light
> gelatin sizing (in the 1% range) can help to a degree.
> Another approach is to deal with this after the print is dry and apply
> either wax or subsequent gum coats. I have a waxed vellum print that has
> measured Dmax of 1.9 using several layers of Gamblin cold wax medium.
>
> My personal preference is for additional layers of expose gum, since it
> offers so many options for color manipulation of the image.
> Finally, a coat of Liquitex Gloss medium diluted 1:8 will also have the
> effect of causing a measurable (though relatively minor half
> stop) increase in Dmax. Again, I think this is because it causes the
> microscopic fibers to lay down and behave.
>
> ...
>
Received on 07/21/06-11:35:32 AM Z