RE: Cyanotype

[Loris Medici <mail@loris.medici.name>]

Jacek, IME 2A+1B (where A is 20% and B is 8%) gives slightly less dmax but
more speed. IIRC, Alberto Novo (and Christina Anderson) showed us that you
get better dmax with higher B concentration, but with the expense of
gradually increasing speed loss and bleeding. (Both!)

Why don't you just coat twice? (I mean 1A+1B x 2...)You'll get very nice
dmax, plus, since the emulsion is more contrasty you'll have better
chances in terms of digital negatives. (If you can't get enough negative
density range that is... But, OTOH, that's a very low probability with
cyanotype since you need a negative with a density range of only log 1.4
or 1.5!) Just add a couple of drops Ilfotol (or Tween) into 10ml coating
solution, brush the first coat, wait until the paper surface is not shiny
(5 to 10 minutes depending on RH and paper), brush the second coat, wait
again until the paper surface is not shiny, then force dry with a hair
dryer and expose. (I prefer to expose bone dry paper because it's very
consistent, cyanotype is pretty sensitive to humidity level.)

Robert is right about wash water. You definitely need neutral to acidic
wash water; but mind that too much acid in the wash water may cause
bleeding and highlight staining depending on the paper you're using. Try a
pinch of citric acid into a liter or two of wash water...

Regards,
Loris.


29 Temmuz 2009, Çarşamba, 4:49 am tarihinde, Robert W. Schramm yazmış:
>
> Instead of double coating, try using two party A solution to one part B
> solution. I think you will get a greater Dmax. Also check your wash water.
> It should be neutral or slightly acidic. If it is not, add some acidic
> acid to it or dilute HCl.
>
> Bob Schramm
>
> Check out my web page at:
>
>   http://www.SchrammStudio.com
>
>> Date: Tue, 28 Jul 2009 22:53:46 +0800
>> From: jacek@jagnight.com
>> Subject: Cyanotype
>> To: alt-photo-process-l@usask.ca
>>
>> Hi Loris,
>>
>> I've been playing around with some new inks in my printer for the past
>> few weeks tweaking them to give me a gradation of ink. I haven't had a
>> chance with any cyanotype printing. Though I was wondering if you had
>> tried a specific method of double printing to increase the Dmax?
>> With the traditional Cyanotype you get an average Dmax of 1.10. What
>> if you were to recoat again (once it is completed and dried) with the
>> Trad cyanotype and registered another negative. Expose for less time
>> to do the shadow areas.
>> Therefore get a higher Dmax to the print?
>> Will this work?
>> I can see it being an expensive exercise, with another negative! :)
>> Just my rambling thoughts...
>> Cheers
>> Jacek
>>
>