Digital BW, The Print

In my latest efforts, I've been reading up on and starting to 
experiment with ways to increase the stability of the carbon pigments.  

One of the more interesting and intriquing factoids I've found is that 
Gum Arabic has been used to disperse and stabilize carbon inks for 
quite a while -- like maybe three thousand years.  Yet in efforts to 
disperse and stabilize the latest carbon nanotubes, Gum Arabic is still 
one of the best.  Additionally, it's safe and in lots of our foods.  It 
is also one of the ingredients in the old carbon photographic printing 
process and is available from Photographers Formulary.

I'll be experimenting with it and attempting to use a centrifuge to do 
accelerated settling testing of different pigment dilution bases and 
approaches.  

I'll post some of my latest notes and thoughts at 
http://www.paulroark.com/BW-Info/Pigment-Stabilization.pdf

Chemists and others, please don't hesitate to correct things I've 
posted if they are wrong (and clearly incomplete).  I make no claims to 
expertise here.  I'm just a curious B&W photographer exploring my new 
medium.

Paul
www.PaulRoark.com

Hi Paul,

You asked for comments, so here goes!

Actually gum was used in gum bichromate prints and carbon prints are done with a gelatin base—both gum and gelatin are colloids that are made sensitive to UV light and harden when Ammonium or Potassium Dichromate is added to them and they are allowed to dry.  They can be used with any color of pigment—the more stable the pigment the more stable the print.  You can also do color separations and make full color gum and carbon prints by doing 3 printings.  Carbon tissue is also used in the photogravure process.  Eggs can also be used as a colloid with the dichromates.  Gum prints and carbon prints are two of the most stable prints known.

All these processes use negatives for contact printing with UV light, so the negative has to be the size of the final print..  Currently a lot of people are making digital negatives rather than shooting large in-camera negatives or using wet process enlarged negatives.

If you experiment with gum, you need something to keep it from spoiling—smells nasty then!

I do primarily Platinum/Palladium printing with digital negatives and am experimenting with polymer plate photogravure, which is turning out very nicely.

Sorry — don't mean to be picky, 

Best Wishes,

Mark Nelson
Precision Digital Negatives
PDN Print Forum @ Yahoo! Groups
Mark Nelson Photography


On Nov 28, 2008, at 10:50:51 PM, pr_roark <pr_roark@...> wrote:

From:   pr_roark <pr_roark@...>
Subject:    [Digital BW] Pigment Stabilization
Date:   November 28, 2008 10:50:51 PM CST
To: DigitalBlackandWhiteThePrint@yahoogroups.com
In my latest efforts, I've been reading up on and starting to 
experiment with ways to increase the stability of the carbon pigments. 

One of the more interesting and intriquing factoids I've found is that 
Gum Arabic has been used to disperse and stabilize carbon inks for 
quite a while -- like maybe three thousand years. Yet in efforts to 
disperse and stabilize the latest carbon nanotubes, Gum Arabic is still 
one of the best. Additionally, it's safe and in lots of our foods. It 
is also one of the ingredients in the old carbon photographic printing 
process and is available from Photographers Formulary.

I'll be experimenting with it and attempting to use a centrifuge to do 
accelerated settling testing of different pigment dilution bases and 
approaches. 

I'll post some of my latest notes and thoughts at 
http://www.paulroark.com/BW-Info/Pigment-Stabilization.pdf

Chemists and others, please don't hesitate to correct things I've 
posted if they are wrong (and clearly incomplete). I make no claims to 
expertise here. I'm just a curious B&W photographer exploring my new 
medium.

Paul
www.PaulRoark.com 





--


[Non-text portions of this message have been removed]

ender100 wrote:
> Hi Paul,
> 
> You asked for comments, so here goes!
> 
> Actually gum was used in gum bichromate prints and carbon prints are done with a gelatin base\u2014both gum and gelatin are colloids that are made sensitive to UV light and harden when Ammonium or Potassium Dichromate is added to them and they are allowed to dry.  They can be used with any color of pigment\u2014the more stable the pigment the more stable the print.  You can also do color separations and make full color gum and carbon prints by doing 3 printings.  Carbon tissue is also used in the photogravure process.  Eggs can also be used as a colloid with the dichromates.  Gum prints and carbon prints are two of the most stable prints known.
> 
> All these processes use negatives for contact printing with UV light, so the negative has to be the size of the final print..  Currently a lot of people are making digital negatives rather than shooting large in-camera negatives or using wet process enlarged negatives.
> 
> If you experiment with gum, you need something to keep it from spoiling\u2014smells nasty then!
> 
> I do primarily Platinum/Palladium printing with digital negatives and am experimenting with polymer plate photogravure, which is turning out very nicely.
> 
> Sorry \u2014 don't mean to be picky, 
> 
> Best Wishes,
> 
> Mark Nelson
> Precision Digital Negatives
> PDN Print Forum @ Yahoo! Groups
> Mark Nelson Photography
> 
> 
> On Nov 28, 2008, at 10:50:51 PM, pr_roark <pr_roark@...> wrote:
> From:   pr_roark <pr_roark@...>
> Subject:    [Digital BW] Pigment Stabilization
> Date:   November 28, 2008 10:50:51 PM CST
> To: DigitalBlackandWhiteThePrint@yahoogroups.com
> In my latest efforts, I've been reading up on and starting to 
> experiment with ways to increase the stability of the carbon pigments. 
> 
> One of the more interesting and intriquing factoids I've found is that 
> Gum Arabic has been used to disperse and stabilize carbon inks for 
> quite a while -- like maybe three thousand years. Yet in efforts to 
> disperse and stabilize the latest carbon nanotubes, Gum Arabic is still 
> one of the best. Additionally, it's safe and in lots of our foods. It 
> is also one of the ingredients in the old carbon photographic printing 
> process and is available from Photographers Formulary.
> 
> I'll be experimenting with it and attempting to use a centrifuge to do 
> accelerated settling testing of different pigment dilution bases and 
> approaches. 
> 
> I'll post some of my latest notes and thoughts at 
> http://www.paulroark.com/BW-Info/Pigment-Stabilization.pdf
> 
> Chemists and others, please don't hesitate to correct things I've 
> posted if they are wrong (and clearly incomplete). I make no claims to 
> expertise here. I'm just a curious B&W photographer exploring my new 
> medium.

Good dispersion qualities but if it is tends to spoil it 
will spoil in printers and that's one of the worst things 
that can happen in a printer. Had some bad luck with an 
Epson 5000 a CIS and  dye inks that got wrong. No fungicide 
etc that could keep the tube system clean.

The hardening of gum arabic in the alternative processes 
could be simulated in inkjet printing with a clear diazo 
component mixed in that hardens the PVA or gelatine medium 
with UV light after printing. Bichromates are not 
recommended. (Form)aldehyde vapor could do the same after 
printing and doesn't have to be mixed in the ink.
It's patented for hologram hardening but not for inkjet yet 
I guess. Maybe tomorrow. Not a healthy process  either. 
There will be inkjet papers with a coating that cross link 
the ink medium they are intended for, we are probably using 
them and see their better waterproof resistance already.

Lately we see more messages here that praise the pre inkjet 
technologies for their archival qualities. Thousand of 
chemists work on inkjet inks and coatings, there must be 
some that are well aware of the pros and cons of the old 
processes and use them were suitable. At the same time they 
must also be well aware of all the new chemistry that is 
available for inkjet ingredients.

-- 
Met vriendelijke groeten, Ernst


|  Dinkla Grafische Techniek  |
|     www.pigment-print.com    |
|             ( unvollendet )            |

[re: gum arabic]
... 
> Good dispersion qualities but if it is tends to spoil ...

I'm keeping an eye on that issue.  The anti-microbial effects of a 
simple piece of copper wire in water are most interesting (silver 
also, but it's more expensive).

...

> Lately we see more messages here that praise the pre inkjet 
> technologies for their archival qualities.

I don't think older technologies are better, but B&W photograph is a 
medium steeped in tradition.  It's interesting that some of the 
materials that have been used for many years may continue to have 
relevance.  Also, given the uncertainties of accelerated age testing, 
looking at materials that have actually stood the test of time is one 
source of predicting future performance.


> Thousand of 
> chemists work on inkjet inks and coatings, there must be 
> some that are well aware of the pros and cons of the old 
> processes and use them were suitable. 

I certainly suspect that all that talent and work going into these 
materials has and will continue to produce some very good results.  
On the other hand, one "pro" to me which is a huge "con" to them is 
that these old materials can't be patented.  If there is a simple 
open-source approach to our medium that works reasonably well, it 
gives us a baseline to judge the value of what the "thousands of 
chemists" can come up with.

Anyway, it's fun.

Paul
www.PaulRoark.com

pr_roark wrote:
> [re: gum arabic]
> ... 
>> Good dispersion qualities but if it is tends to spoil ...
> 
> I'm keeping an eye on that issue.  The anti-microbial effects of a 
> simple piece of copper wire in water are most interesting (silver 
> also, but it's more expensive).
> 
> ...
> 
>> Lately we see more messages here that praise the pre inkjet 
>> technologies for their archival qualities.
> 
> I don't think older technologies are better, but B&W photograph is a 
> medium steeped in tradition.  It's interesting that some of the 
> materials that have been used for many years may continue to have 
> relevance.  Also, given the uncertainties of accelerated age testing, 
> looking at materials that have actually stood the test of time is one 
> source of predicting future performance.
> 
> 
>> Thousand of 
>> chemists work on inkjet inks and coatings, there must be 
>> some that are well aware of the pros and cons of the old 
>> processes and use them were suitable. 
> 
> I certainly suspect that all that talent and work going into these 
> materials has and will continue to produce some very good results.  
> On the other hand, one "pro" to me which is a huge "con" to them is 
> that these old materials can't be patented.  If there is a simple 
> open-source approach to our medium that works reasonably well, it 
> gives us a baseline to judge the value of what the "thousands of 
> chemists" can come up with.

Paul,

The message wasn't meant to be harsh on what you intend to 
do. I like your experiments. But no so long  ago all kinds 
of old processes were mentioned here in the mood that all 
the inkjet developments right now were not worth what was 
available in the past. Wilhelm swept aside in the same thread.
Strange as I observed with Wilhelm that in ten years time we 
got better color prints that last longer and are easier to 
make than 99% of the color prints made before that time. 
Carbon color may have been better but that should still be 
tested. B&W inkjet prints improved a lot on the same aspects 
but will not yet equal the best archival processes of the 
past. At least what is available right now in inkjet B&W 
will be equal to the quality most non-archival processes 
delivered then. I wrote a message as a reply on that thread 
but kept it in draft, didn't want to disturb the peace then.

That copper wire represents quite accurate the difference 
between the analogue B&W chemistry and today's inkjet 
chemistry ... the absence of heavy metals in inkjet prints. 
The archival quality of analogue B&W depended a lot on that 
whether it was its toxic quality or to harden the gelatine 
emulsion in alternative processes, both making the prints 
less biodegradable :-) That will be much harder to achieve 
in inkjet prints in the eco political climate of today and 
right so. With that in mind a lot of the "archival" 
knowledge of the past can not be used in inkjet printing.

Patents in the USA can be applied for whether there was 
prior art or not. At least the last decade it must be harder 
to have an idea that can't be patented than the opposite. 
Gum arabic is used in inkjet ink formula that are patented. 
It's just an ingredient among many.

-- 
Met vriendelijke groeten, Ernst


|  Dinkla Grafische Techniek  |
|     www.pigment-print.com    |
|             ( unvollendet )            |

Ernst,

... 
> The message wasn't meant to be harsh ...

Nor was it taken as such.  I always appreciate your very 
knowledgeable comments.

>... B&W inkjet prints improved a lot ... 
> but will not yet equal the best archival processes of the 
> past. 

It'll be tough to rival the image stability of the noble metals 
(silver not being among them).  It would be interesting to see a good 
test that compared the typical lightly selenium toned silver print to 
a 100% carbon image, but I suspect it'd take a very long time to see 
any significant difference.  Frankly, I stopped the fade testing 
because the good carbon pigments are so good the issue is just not a 
serious factor for me.  Additionally, other factors, such as 
oxidizers (some of which silver is very susceptible to, protected 
mostly by the gelatin), have become limiting factors and are hard to 
test, at least by me.


> That copper wire represents quite accurate the difference 
> between the analogue B&W chemistry and today's inkjet 
> chemistry ... the absence of heavy metals in inkjet prints. 
> The archival quality of analogue B&W depended a lot on that 
> whether it was its toxic quality or to harden the gelatine 
> emulsion in alternative processes, both making the prints 
> less biodegradable :-) That will be much harder to achieve 
> in inkjet prints in the eco political climate of today and 
> right so. With that in mind a lot of the "archival" 
> knowledge of the past can not be used in inkjet printing.

So, here I am suggesting a way to add heavy metal ions to our brew.  
At the risk of losing my green credentials, the biodegradability of 
my prints has not been a major focus for me.

 
> Patents in the USA can be applied for whether there was 
> prior art or not. ...

They've become major weapons of the large companies in their attempts 
to suppress competition.  In my previous life I discovered and 
initially worked up a case the involved AT&T using its silicon patent 
portfolio against competitors, including a little company called 
Intel.  The good news is the the little fish can swim circles around 
the whales.

Genug ...

Paul
www.PaulRoark.com

Paul-

It's exactly what we used to take hundreds of aerial photographs and 
make maps of an area.

Each silver print was cut and torn, then coated with gum arabic to hold 
it down to the other layers.  I cannot remember it migrating or causing 
discolorations from aging at all.

I think you can still get it in a powdered form and mix as you need it.

Seth

We can share some of the knowledge we have learn in our research to
make archival inks on the topic of stabilizing carbon pigments.

There exist at least two kind of carbon pigment currently used in the
ink industry. The first kind correspond to the pigments obtained in
the traditional way: lamp black, acetylene black, etc.
They need to be stabilized appropriately with a dispersant. There are
probably several hundred dispersant to do that: the most common in the
ink industry are acrylic resins. However, there are also natural
polymer that have dispersing properties. Specific examples of natural
polymer dispersants include proteins such as glue, gelatin, casein and
albumin; natural rubbers such as gum arabic and tragacanth gum;
glucosides such as saponin. Almost all of them need a biocide if you
need to keep the dispersion for long time. We successfully tested
thymol, which is a mild, natural biocide.
A very easy to obtain (not natural, as it is an acrylic resin)
dispersant is PVA (the common white glue).
The second kind of carbon pigments used to make inks are so-called
"surface-modified carbon black". They are obtained from regular carbon
black by oxidization of the pigment surface in sodium hypochlorite for
several hours at high temperature. After the treatment, the
coalescence of the pigments is much diminished and they need no
dispersant to be stabilized.

We suspect that MIS Eboni/Image Specialist 1082 use surface modified
pigments.

Hope these informations are of some help.

Daniela
www.mantinieri.com