Re: palladium drydown and developer

Gee, that's interesting. Ansel wrote that typically, exposures should be
about 10% less after a perfect print seen wet to compensate for dry-down.

Dry down darkening is a phenomenon caused when the solids in the aggregate
(like gelaten) become closer together when dry.

.09t or less 10% . . . what choices!

S. Shapiro
----- Original Message -----
From: "Ryuji Suzuki" <rs@silvergrain.org>
To: <alt-photo-process-l@usask.ca>
Sent: Friday, July 21, 2006 10:35 AM
Subject: 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 07/21/06-11:45:02 AM Z