From: Bob and Carla (bb333@earthlink.net)
Date: 05/20/03-08:17:00 AM Z
Sandy,
When you add the pot-dichromate to the developer, does it's
potency diminish progressively as I believe hydrogen peroxide does,
or does it remain constant a constant value that is adjusted to the
developer?
Bob
> Jacques,
>
> I discuss contrast control in the article.
>
> "Contrast can be controlled by the addition to the developer of a few ml of a 5% potassium dichromate solution. The practical limit ranges from as little as 1 ml per liter of developer up to about 16 ml per liter. This allows the use of negatives from a DR as low as about 1.2 to a maximum of about 2.2. If too much dichromate is added, printing times will increase considerably and the image will take on a granular look."
>
> Sandy
>
>
>
> Sandy,
> Great article, but how do I control the contrast? Dicromate in the sensitizer?
> Jacques
>
> Linas Kudzma escreveu:
> Sandy,
> I just read your Kallitype article on unblinkingeye.com. Excellent! I???ve experimented with the procedure you posted here a while back with some success.
>
> During my trials I used a different clearing method (my Pd/Pt development/clearing method) resulting in some variation from what you describe. Basically, what I do is develop for about 30-45 seconds, decant(and save)the developer and then clear with one or two changes of a hot (120F) solution of citric acid (approx 5 gm citric in about 1 liter) for about 5 min. My reasoning is that any longer in the developer (potassium oxalate for Pd/Pt, sodium citrate for Kallitype) does not contribute to the image formation, rather only undesirably clears iron into the developer, which I intend to reuse. So I change from developer to the clearing bath earlier. My hot citric acid clearing bath works great for normal Pd/Pt. However, with Kallitype this hot clearing bath turns the Kallitype image bright yellow. Subsequent Pd or Pt toning by your method turns this yellow back to a strong dark image, which while beautiful in it???s own way, is subtly less sharp than my Pd/
> Pt prints. Even if the color is identical, I can distinguish these Kallitypes from my Pd/Pt prints. This was on Crane's 90# Cover or Stonehenge.
>
> I suspect my hot citric acid bleaching and subsequent toning is the difference. Anyone else see such a yellow image after clearing? By yellow, I mean bright yellow, not light brown.
>
> Linas
>
>
> Linas Kudzma
> lkudzma@earthlink.net
>
>
> Re: Gold toners and Kallitype
> Cor,
>
>
> The kallitype article is now up on Unblinking Eye. The direct link to the article is http://unblinkingeye.com/Articles/Kallitype/kallitype.html
>
> There is another gold toning formula in the article that has slightly different working characteristics than the one based on citric acid.
>
> Perhaps someone else can comment on Reilly's remarks about acidic gold toners. I am aware of a need to print slightly deeper when using gold toner than when using platinum or palladium toners. As I note in the article, with gold toners "image contrast is increased by about a step through loss of density in the high values, but Dmax values (shadows) are changed little if at all." With one recent image I needed an exposure of 250 units with a gold-toned print to get the same final density as 230 with a palladium-toned print.
>
> However, even with the acidic gold toner the maximum density of the gold-toned kallitypes I have made is as high as those toned with palladium and platinum toning. On Stonehenge paper the reflective reading of both is around 1.52. Those who print on art papers such as Stonehenge with either kallitype or Pt/Pd will recognize that this is a very high maximum density and about the maximum achievable with either process.
>
> Sandy
>
>
>
>
>
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