RE: VDB

On Sun, 16 Oct 2005, Loris Medici wrote:

> I guess good Dmax is a little bit subjective concept. Coming from silver
> gelatine printing (and quadtone b&w inkjet printing), the max. density I get
> with alt-process prints looks always weak to my eyes.

Hi Loris,

Your formula is the classic formula AFAIK, so I figure one or all of the
following:

Your standards are higher than mine;

There's TOO MUCH D-max in silver gelatin and quadtone inkjet, so it ruins
you.

Papers today aren't as D-Maxy as the prewar (pre-WWII !) Strathmore I had
a big stash of from NY Central Artists Materials (this I'm pretty sure of,
BTW).

All of the above -- though I'm not familiar with that COT.... Still, a
couple of other thoughts -- maybe that "dedicated brush" is one of the
kind that just lays on enough emulsion for platinum? A foam applicator may
slosh on more fluid, possibly the total amount in one coat you get with
two?

I also wonder (just curious -- your EXTREME precision has that effect!),
if a one-minute fix would give greater D-max. In my fixer tests there was
a noticeable difference in bleaching between one minute fix and 2
minutes... I adjusted around it, and found 2-minute fix, or 1-1/2, was
fine (for my standards, anyway), still, I wonder....

But the whole fixing issue with VDB seems peculiar. A couple of my
students fell in love with the print color UNFIXED, and we found that
leaving the print unfixed, but with a good wash, it seemed not to change
after TWO HOURS re-exposure under BL fluorescents. That doesn't mean it
didn't change in time of course -- but it was at least possible to believe
that the main function of the fixer was to darken the brown !!

cheers,

Judy

>
> I use the formula given in Wynn White's article @ unblinkingeye.com
> (http://unblinkingeye.com/Articles/Vandyke/vandyke.html). Formula says:
>
> Solution A
> Ferric Ammonium Citrate 9.0 gm
> Distilled Water 33.0 ml
>
> Solution B
> Tartaric Acid 1.5 gm
> Distilled Water 33.0 ml
>
> Solution C
> Silver Nitrate 3.8 gm
> Distilled Water 33.0 ml
>
> My chemicals are all good. My scales are all good (no problems with Ziatype,
> Cyanotype). My silver nitrate is white, it shows no precipitation and/or
> cloudyness when mixed with the distilled/deionized water I use. I use a dark
> amber coloured container with plastic caps (double caps). I use dedicated
> brush and plastic pipette for measuring coating solution and for
> application. Paper comes from its original packaging, no problems with other
> processes. No extra sizing (it's Cot 320; extremely good sizing on the front
> side). I know there are people printing platinum on that paper (another
> process that doesn't like gelatine sizing) so I guess its sizing is
> syntethic (aquapel?). I wash in 1% citric acid (in order to get rid of all
> unexposed sensitizer), I use plain 2% sodium thiosulfate fixer (no other
> chemicals added). Fixing time is 1 min. I expose right after drying the
> paper (5mins flat, then 25mins cold air fan).
>
> I get good Dmax by double coating and toning in gold before fixing. Never
> got good Dmax by single coating.
>
> Regards,
> Loris.
>
> -----Original Message-----
> From: Judy Seigel [mailto:jseigel@panix.com]
> Sent: 16 Ekim 2005 Pazar 08:11
>
> To: alt-photo-process-l@sask.usask.ca
> Subject: RE: VDB
>
>
> On Thu, 13 Oct 2005, Loris Medici wrote:
>
>> I'm sure I can't get even close to 1.2 with one coat VDB (subjective
>> comment: didn't measure, don't have a densitometer). Your 1.5 is very
>> close to semi-matte RC paper max. density (which is around 1.6
>> IIRC)... If I were getting such density I'd never bother with double
>> coating. I have Stonehenge paper sitting somewhere, will try it for VDB
> when I will have time...
>
> I'm puzzled by the reports about insufficient VDB density... also emulsion
> ruination... I've used single coat VDB emulsion aged nearly 2 years, plated
> out in the bottle, full of black precipitate, etc. etc.
> without problems and with good d-max.
>
> Wondering about:
>
> Is it possible a weaker formula circulates? What formula are folks using?
>
> Are all chemicals known to be good?
>
> Do you trust your scale? (That's a relatively small amount of silver
> nitrate, so truth in weighing matters.) Is the silver nitrate still white?
>
> And the water: We had a problem when the silver precipitated out as soon as
> it was added to the water, BEFORE combining with the other solutions.
> The hardware store had sold us tap water in a "distilled" water container.
> (On a hunch I brought it to the chem dep't which confirmed.)
>
> (I note that I was mixing the silver solution in a babyfood jar with a metal
> cap... When it precipitated right out, I thought it was the cap. I suppose
> the cap didn't help, but it was the water.)
>
> Are you sure your container is light tight? Not all colored plastic is.
> (I kept the brown glass bottle, with black plastic cap, in a dark closet
> when not in use.)
>
> Are you using a *dedicated* applicator -- say, foam brush that doesn't go
> into anything else?
>
> Does the paper lie on a *clean* surface for coating? (If stroke extends
> over the edge & onto a dirty surface, it picks up stuff.)
>
> Are you gelatin sizing? VDB does NOT like gelatin size.
>
> And fixer -- I found that two minutes in a plain fix of (percent I'd have to
> look up, but much weaker than standard fix) was the longest and strongest
> you could use without bleaching. (I probably have it somewhere, probably in
> P-F, but it made an enormous difference.)
>
> Also, I mention what maybe most folks know, but the books seem to have wrong
> -- The first rinse, in plain water, before fixing, should not be just "until
> the water runs clear." A student did a variables test and found a much
> brighter deeper print with a 5 minute rinse before fixing.
>
> Heat drying the emulsion kills D-max, but storage before exposure and before
> development can also cut densitity. And probably more variables I'm not
> thinking of now...
>
> cheers,
>
> Judy
>
>
Received on Sun Oct 16 21:08:01 2005