[Alt-photo] Re: DAS

[Loris Medici]

Thank you Sandy, I'll investigate the stain issue. OTOH, I space isn't
an issue to me; I have 10 large sheets of plexiglass for drying tissue
face down, all I need is about 15-16' of wall space in my hallway - to
lean the plexi sheets against...

Kees, can you tell us a little more about the stain? I plan to use
(thin but strong) Masa paper as tissue support and want to do single
transfer. Will I have to use permanganate for clearing? If yes, what's
the down side of this procedure?

Regards,
Loris.


2013/4/16 Sandy King <sanking at clemson.edu>
>
>
> Loris,
>
> From what I have read the stain might indeed be  a problem with single
> transfer carbon where the final support is fiber based. Removing the stain
> apparently takes some fairly aggressive clearing.
>
> I applaud the research and experimentation with DAS but from my
> perspective the disadvantages (cost and supply issues, staining, and space
> requirements for drying large number of pre-sensitized sheets) outweigh the
> advantages (lack of dark effect, long-term stability of pre-sensitized
> tissue) of DAS for monochrome carbon printing.
>
> Sandy
>
>
>
> On Apr 16, 2013, at 4:54 AM, Loris Medici wrote:
>
> > Thanks for the info, I'm very interested and will try to find a local
> > source. Importing chemicals is a PIA here in Turkey - especially those
> > with a fancy name like this one! ;)
> >
> > Who's your local source in the Netherlands? I have friends there,
> > maybe they can bring me some when they're going to visit Turkey...
> >
> > Stain is non-important to me; I'm not planning to use it for casein
> > and alike, I just want to make pre-sensitized carbon tissue for
> > transfer - I REALLY detest the long wait after sensitizing!!!
> >
> > Regards,
> > Loris.
> >
> >
> > 2013/4/16 Kees Brandenburg <workshops at polychrome.nl>:
> >> Sigma-Aldridge is indeed selling it at crazy prizes. These small
> >> quantities are meant for lab testing. We need more industrial sources. In
> >> the past DAS was used as an ingredient for printing fluorescent sceens on
> >> the inside of cathode ray (tv) monitors. It's allways interesting to keep an
> >> eye on (obsolete) high tech procedures. The printing of micro stuctures on
> >> silicium wafers is also still a photo lithographic process too for example!
> >>
> >> I have bought my first 250 grams of DAS here in the Netherlands at
> >> about € 1,15  per gram. I also have imported it directly from China, which
> >> was somewhat adventurous but I got it at about € 0,40 per gram, shipping
> >> included. The group buy was a little cheaper than that, but it was a (now
> >> sold out) rest of an older batch Secant (secantchemicals.com) carried.This
> >> is the same source Tod Gangler uses as ingredient for his color carbon
> >> printing as far as I know.  It is unshure if there will be new batches at
> >> Secant in the future. Who manufactures it for Secant is unclear. That's why
> >> I tried the Chinese.
> >>
> >> What I should say is that DAS has also a 'staining problem'. This is
> >> hardly visible when doing double transfer carbon, because the temporary
> >> support (polyester or vinyl) doesn't hold the stain. That's different with
> >> direct transfer carbon and, to some extent, casein. The original Ultrastable
> >> (also DAS pre-sensitized) clearing recipe uses a (very) dilute potassium
> >> permanganate solution followed by a sulfite bath. This reintroduces toxicity
> >> and a strong oxidizer, with the permanganate. I would be very intersted to
> >> find alternative, and cleaner clearing options!
> >>
> >> regards,
> >>
> >> Kees
> >>
> >>
> >> On 16 apr. 2013, at 09:16, Loris Medici <mail at loris.medici.name> wrote:
> >>
> >>> Thank you much for the info Kees - much appreciated. The only source I
> >>> can buy is thru Sigma-Adrich, and the have a ~EUR 55 price tag per
> >>> 10g; absolutely prohibitive! (I can buy kg's of gelatin, pigment,
> >>> dichromate and acetone or alcohol for a song here in Turkey...)
> >>>
> >>> Regards,
> >>> Loris.
> >>
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