[Alt-photo] Alt-photo-process-list Digest, Vol 51, Issue 2

Info (GEO) info at geostudio.com
Tue Mar 3 22:42:33 UTC 2015


Hi Loris, hello friends,

I use a Platinum/Palladium printing process (4/0/3/1 ratio), with coating 
paper at room temperature and ambient humidity (35%-40% RH). Natural drying 
over a frame for an hour. Before printing the paper humidifies for about 15 
minutes on a sandwich consisting of wet blotting paper (bottom) goretex (in 
the middle) and paper (above), covered with a plastic sheet. The 
humidification system is simple and effective, and is used in the 
restoration of ancient paper to facilitate the return to the flatness and 
the relaxation of the fiber (see 
http://www.thelevantinefoundation.org/userfiles/files/Humidification%20hand-out.pdf).

One last thing, I found another compound called Grace's SYLOID which 
guarantees the maintenance of the opacity of the medium on which it is used. 
Get these products won't be easy, at least in Italy, but I think it is worth 
persevering. I would like to thank those of you who can give me some info on 
how and where to order them. Certainly not all subjects require particular 
attention to achieving high Dmax, but I think the simplicity of preparation 
of these suspensions, compared to the difficulty of dry coating, be of help 
to many of us.

Massimo



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Subject: Alt-photo-process-list Digest, Vol 51, Issue 2

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Today's Topics:

   1.  Increase in Dmax (Info (GEO))
   2. Re:  Increase in Dmax (Loris Medici)
   3. Re:  Increase in Dmax (David Pitcher)
   4. Re:  Iron(III) Salts vs. Dichromates - Photo Relief Processes
      (Kees Brandenburg)


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Message: 1
Date: Mon, 2 Mar 2015 13:51:39 +0100
From: "Info \(GEO\)" <info at geostudio.com>
To: <alt-photo-process-list at lists.altphotolist.org>
Subject: [Alt-photo] Increase in Dmax
Message-ID: <8CD274A6B7964AAEBA5EDAF261124EBF at STBHOME>
Content-Type: text/plain; format=flowed; charset="UTF-8";
reply-type=original

I tested paper precoat "Revere Platinum" with Fumed silica suspension Sigma
Aldrich (LUDOX) applied with coating road.
The Dmax increases from 1.45 to 1.65 (measured by densitometer TOBIAS
IQ150), without streaks, grainless and with good uniformity, but the finish
looks like semi-matt, not good for me.
Now I try with a preparation of Evonik (AERODISP) that should not alter the
opacity of the paper and I'll let you know.
Has anyone had any experiences with these products or with similar
processes?

Cheers,
Massimo


-----Messaggio originale----- 
From: alt-photo-process-list-request at lists.altphotolist.org
Sent: Monday, March 02, 2015 1:00 PM
To: alt-photo-process-list at lists.altphotolist.org
Subject: Alt-photo-process-list Digest, Vol 51, Issue 1

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Today's Topics:

   1.  Iron(III) Salts vs. Dichromates - Photo Relief Processes
      (David Pitcher)


----------------------------------------------------------------------

Message: 1
Date: Sun, 1 Mar 2015 19:44:44 -0800
From: David Pitcher <pitcherd1 at msn.com>
To: <alt-photo-process-list at lists.altphotolist.org>
Subject: [Alt-photo] Iron(III) Salts vs. Dichromates - Photo Relief
Processes
Message-ID: <BAY402-EAS2157A9EBA5EACC562159005E1100 at phx.gbl>
Content-Type: text/plain; charset="us-ascii"

I am wondering if any has done research into why Dichromate's became more
popular in colloid relief based processes such as Carbon, Casein, and Gum.
This is interesting given the instability of Dichromate's and the dark
reaction causing fogging.



It would seem that a combination of simple ferric salts have a strong
tanning action on gelatin and turns in insoluble. There are published
details that there were discoveries in which a double salt such as ammonium
ferric oxalate or citrate would prevent the reaction of the simple ferric
salt, ferric chloride, until exposed to UV radiation and begin free radical
polymerization.  Once exposed simple bath in hydrogen peroxide and then a
water bath would wash away gelatin that was not exposed leaving a hardened
gelatin relief.



Cheers,

David







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Message: 2
Date: Mon, 2 Mar 2015 14:59:51 +0200
From: Loris Medici <mail at loris.medici.name>
To: The alternative photographic processes mailing list
<alt-photo-process-list at lists.altphotolist.org>
Subject: Re: [Alt-photo] Increase in Dmax
Message-ID:
<CANYkkb1adObW1Fa2idwnvcaBGUnLswrbre5A0_E1tm07geYfaQ at mail.gmail.com>
Content-Type: text/plain; charset=UTF-8

Hi Massimo, interesting information. Thanks for sharing.

I went to Sigma Aldrich site and it says the product has a pH value 9.8,
which is pretty alkaline. Silica should be pH neutral, therefore, I think
there's something more in the product - apart SiO2, that helps keeping
silica in suspension, which is alkaline...

Which process were you using?

Regards,
Loris.


2015-03-02 14:51 GMT+02:00 Info (GEO) <info at geostudio.com>:

> I tested paper precoat "Revere Platinum" with Fumed silica suspension
> Sigma Aldrich (LUDOX) applied with coating road.
> The Dmax increases from 1.45 to 1.65 (measured by densitometer TOBIAS
> IQ150), without streaks, grainless and with good uniformity, but the 
> finish
> looks like semi-matt, not good for me.
> Now I try with a preparation of Evonik (AERODISP) that should not alter
> the opacity of the paper and I'll let you know.
> Has anyone had any experiences with these products or with similar
> processes?
>
> Cheers,
> Massimo
>


------------------------------

Message: 3
Date: Mon, 2 Mar 2015 07:18:18 -0800
From: David Pitcher <pitcherd1 at msn.com>
To: "alt-photo-process-list at lists.altphotolist.org"
<alt-photo-process-list at lists.altphotolist.org>
Subject: Re: [Alt-photo] Increase in Dmax
Message-ID: <BAY402-EAS160C596CB4E49216B82FF10E1100 at phx.gbl>
Content-Type: text/plain; charset="us-ascii"

Here is a link to a full product description of the Ludox line from Grace, 
the manufacture.  The are using a sodium anion to keep the silica in 
suspension. 
https://grace.com/general-industrial/en-us/Documents/ludox_br_E_2012_f120504_web.pdf

I have worked with the more acidic version in attempts at creating 
alternative subbing solutions for glass or non porous surfaces.

Cheers,
David

Sent from my iPad

> On Mar 2, 2015, at 5:00 AM, Loris Medici <mail at loris.medici.name> wrote:
>
> Hi Massimo, interesting information. Thanks for sharing.
>
> I went to Sigma Aldrich site and it says the product has a pH value 9.8,
> which is pretty alkaline. Silica should be pH neutral, therefore, I think
> there's something more in the product - apart SiO2, that helps keeping
> silica in suspension, which is alkaline...
>
> Which process were you using?
>
> Regards,
> Loris.
>
>
> 2015-03-02 14:51 GMT+02:00 Info (GEO) <info at geostudio.com>:
>
>> I tested paper precoat "Revere Platinum" with Fumed silica suspension
>> Sigma Aldrich (LUDOX) applied with coating road.
>> The Dmax increases from 1.45 to 1.65 (measured by densitometer TOBIAS
>> IQ150), without streaks, grainless and with good uniformity, but the 
>> finish
>> looks like semi-matt, not good for me.
>> Now I try with a preparation of Evonik (AERODISP) that should not alter
>> the opacity of the paper and I'll let you know.
>> Has anyone had any experiences with these products or with similar
>> processes?
>>
>> Cheers,
>> Massimo
> _______________________________________________
> Alt-photo-process-list | altphotolist.org


------------------------------

Message: 4
Date: Mon, 2 Mar 2015 16:40:52 +0100
From: Kees Brandenburg <workshops at polychrome.nl>
To: alt-photo-process-list at lists.altphotolist.org
Subject: Re: [Alt-photo] Iron(III) Salts vs. Dichromates - Photo
Relief Processes
Message-ID: <5FF7563D-28A3-4293-A92D-B6C698F7EF8D at polychrome.nl>
Content-Type: text/plain; charset=utf-8

Hi David,

I think there's a simple reason: dichromates are very good at what they do 
in these processes. I don't think they are unstable and the dark effect is 
something one can live with. The toxicity is the biggest problem and the 
best reason to avoid them.

Alternatives like the (complex) Fe(III) salts work fine as Halvor Bjørngård 
showed in the Chiba process 
(http://polychrome.nl/file_download/4/TheChibaSystem-HR.pdf) and of course 
diazidostilbene works very well for carbon and casein.
I have tried the mix of simple and complex iron salts but my pigmented 
gelatin turned into a sticky mess. Which might not prove it won't work 
though....

Currently I am testing DAS and ferric salts for oilprinting. The high relief 
with the ferric salt is very nice for an oil print!

Kees



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