Digital BW, The Print

My reading indicates that electrostatically stabilized pigment
dispersion approaches are pH sensitive.  That is, if the pH is off too
much, the pigments may not stay suspended as well.  I believe this form
of stabilization approach is used by Eboni (some speculation here) and
the HP Vivera pigments (HP in combination with steric stabilization).

My cheap new pH meter indicates that Eboni and HP Grey inks are close to
pH 8 (HP perhaps a bit above and Eboni just below).  The bases I most
often use today are closer to pH 6, if not a bit less. I think that
increasing the pH of the base we use to dilute the carbon inks might
improve the ink mixes we make.

Triethanolamine (often referred to as TEA) is, according to Wikipedia,
often used as a "pH balancer in cosmetic preparations in a variety of
different products - ranging from skin lotion, eye gels, moisturizers,
shampoos, shaving foams etc."  The HP Vivera MSDSs disclose that it is
used in them.

TEA has been used for some time in photographic applications and is
available at Photographers' Formulary.  See
http://www.photoformulary.com/DesktopModules/StoreProductDetails.aspx?pr\
oductID=588&tabid=0&tabindex=0&categoryid=0&selection=0&langId=0&Search=\
triethanolamine
<http://www.photoformulary.com/DesktopModules/StoreProductDetails.aspx?p\
roductID=588&tabid=0&tabindex=0&categoryid=0&selection=0&langId=0&Search\
=triethanolamine>

Just a few drops of TEA in 10 grams of C6 base
(http://www.paulroark.com/BW-Info/Ink-Mixing.pdf
<http://www.paulroark.com/BW-Info/Ink-Mixing.pdf> ) takes the pH up to
8.  Cheap Litmus paper makes it easy to mix and measure, slowly, until
the pH test strip indicates that pH 8 has been reached.

TEA might be a contender for the next ink mixing base.

(Again, I'm not a trained chemist, and all comments are most welcomed.)

Paul

www.PaulRoark.com <http://www.PaulRoark.com>





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

TEA is cited in Epson ink patents as a suitable pH modifier both by
itself and in conjunction with or substituted by others such as
metallic and ammonium hydroxides. It's generally referenced as under
1% by weight total. 

Regards
Duane



--- In DigitalBlackandWhiteThePrint@yahoogroups.com, "pr_roark"
<pr_roark@...> wrote:
>
> 
> My reading indicates that electrostatically stabilized pigment
> dispersion approaches are pH sensitive.  That is, if the pH is off too
> much, the pigments may not stay suspended as well.  I believe this form
> of stabilization approach is used by Eboni (some speculation here) and
> the HP Vivera pigments (HP in combination with steric stabilization).
> 
> My cheap new pH meter indicates that Eboni and HP Grey inks are close to
> pH 8 (HP perhaps a bit above and Eboni just below).  The bases I most
> often use today are closer to pH 6, if not a bit less. I think that
> increasing the pH of the base we use to dilute the carbon inks might
> improve the ink mixes we make.
> 
> Triethanolamine (often referred to as TEA) is, according to Wikipedia,
> often used as a "pH balancer in cosmetic preparations in a variety of
> different products - ranging from skin lotion, eye gels, moisturizers,
> shampoos, shaving foams etc."  The HP Vivera MSDSs disclose that it is
> used in them.
> 
> TEA has been used for some time in photographic applications and is
> available at Photographers' Formulary.  See
>
http://www.photoformulary.com/DesktopModules/StoreProductDetails.aspx?pr\
>
oductID=588&tabid=0&tabindex=0&categoryid=0&selection=0&langId=0&Search=\
> triethanolamine
>
<http://www.photoformulary.com/DesktopModules/StoreProductDetails.aspx?p\
>
roductID=588&tabid=0&tabindex=0&categoryid=0&selection=0&langId=0&Search\

> =triethanolamine>
> 
> Just a few drops of TEA in 10 grams of C6 base
> (http://www.paulroark.com/BW-Info/Ink-Mixing.pdf
> <http://www.paulroark.com/BW-Info/Ink-Mixing.pdf> ) takes the pH up to
> 8.  Cheap Litmus paper makes it easy to mix and measure, slowly, until
> the pH test strip indicates that pH 8 has been reached.
> 
> TEA might be a contender for the next ink mixing base.
> 
> (Again, I'm not a trained chemist, and all comments are most welcomed.)
> 
> Paul
> 
> www.PaulRoark.com <http://www.PaulRoark.com>
> 
> 
> 
> 
> 
> [Non-text portions of this message have been removed]
>

--- In DigitalBlackandWhiteThePrint@yahoogroups.com, "pr_roark"
<pr_roark@...> wrote:
>
> 
> increasing the pH of the base we use to dilute the carbon inks might
> improve the ink mixes we make.
> 
> Triethanolamine (often referred to as TEA) is, according to Wikipedia,
> often used as a "pH balancer in cosmetic preparations in a variety of
> Paul
> 


Hi,
   Perhaps I can help a bit here.  I am a biochemist, and I've given
more lectures about pH than I care to think about.  What the author at
Wikipedia probably should have written is that TEA is a pH "buffer". 
A buffer is a compound that can readily combine with or dissociate
from hydrogen ions.  By absorbing changes in the hydrogen ion
concentration, the buffer helps keep the pH (which is just a measure
of hydrogen ion concentration) constant when other chemical changes
may perturb it.  Different compounds are effective as buffers at
different pH values.  TEA is a good buffer around pH 8.  

The effectiveness of a buffer also depends on how much is present.  
The usual practice is to make a solution at the buffer concentration
that is needed and then adjust the pH to the desired value by adding
an acid or base.  If you just add TEA to water, it will initially have
a quite high pH, and you would need to add an acid to lower it's pH to 8. 

 What I don't have any idea of is how much TEA would be needed to
maintain the ink solution at pH 8.  Paul's "few drops in 10 mL" would
work out to about 0.1 M, which I would have guessed would be pretty
effective.  I'm a bit surprised that it takes that much to raise the
pH to 8, unless photoFlo is more acidic than I ever realized.

I'm not sure that this helps much, but maybe it provides a bit of
background.

David

--- In DigitalBlackandWhiteThePrint@yahoogroups.com, "dpgoldenberg33" 
<dpgoldenberg33@...> wrote:
>
> ... TEA is a pH "buffer"...

> I'm not sure that this helps much, but maybe it provides a bit of
> background.
> 
> David

Thanks David, it does help my understanding.

Paul
www.PaulRoark.com

Paul, A bit more info regarding this from Epson. The latest patent
data(oct/nov 08) show them using both acid and base buffers to
maintain pH levels to a declared optimal level between 7 and 8.5 for
very recent inks. The acidic buffer can also be a number of things but
one mentioned is citric acid, another old photographic standby.
Also mentioned is the reason for the pH range. Apparently the print
head coatings can be disassociated and jets damaged by levels below
and above the stated range while all is well within that range.

As an aside, the EDTA listed in regard to the Tilex product also turns
out to be a low level ingredient in a number of their ink formulations
so is unlikely to be a problem so long as a mix is within above pH limits.

Regards
Duane




--- In DigitalBlackandWhiteThePrint@yahoogroups.com, "pr_roark"
<pr_roark@...> wrote:

>
> 
> My reading indicates that electrostatically stabilized pigment
> dispersion approaches are pH sensitive.

Hi Duane,


> A bit more info regarding this from Epson. The latest patent
> data(oct/nov 08) show them using both acid and base buffers to
> maintain pH levels to a declared optimal level between 7 and 
> 8.5 for very recent inks.

The HP Grey comes in at 8.83 according to my new but cheap pH meter 
(calibrated to its 7.01 buffer solution).

> The acidic buffer can also be a number of things but
> one mentioned is citric acid, another old photographic standby.

Yes, that is the obvious one that came to mind for me also.

> Also mentioned is the reason for the pH range. Apparently the print
> head coatings can be disassociated and jets damaged by levels below
> and above the stated range while all is well within that range.

That's good to know.

Thanks for the info.

(As an amusing aside, I received a "We've missed you, Paul" canned e-
mail from HP to my Verizon e-mail an hour after my post today 
regarding their grey ink.  The products they had in their database 
that I'd purchased are many years old, and I've not been on their e-
mail list for year.  It's good to know they're listening.)

Paul
www.PaulRoark.com

Paul,

An interesting note that I found in the past; "distilled water" that 
we think is neutral PH can often be around 6.0 or so. Another note; 
on the oil platform we used tri-ethylene glycol to remove water from 
natural gas. Because our gas had H2S in it, the TEG would become 
acidic (around 4.0), we used TEA to raise the PH on the TEG back to 
7.0.
--- In DigitalBlackandWhiteThePrint@yahoogroups.com, "pr_roark" 
<pr_roark@...> wrote:
>
> Hi Duane,
> 
> 
> > A bit more info regarding this from Epson. The latest patent
> > data(oct/nov 08) show them using both acid and base buffers to
> > maintain pH levels to a declared optimal level between 7 and 
> > 8.5 for very recent inks.
> 
> The HP Grey comes in at 8.83 according to my new but cheap pH meter 
> (calibrated to its 7.01 buffer solution).
> 
> > The acidic buffer can also be a number of things but
> > one mentioned is citric acid, another old photographic standby.
> 
> Yes, that is the obvious one that came to mind for me also.
> 
> > Also mentioned is the reason for the pH range. Apparently the 
print
> > head coatings can be disassociated and jets damaged by levels 
below
> > and above the stated range while all is well within that range.
> 
> That's good to know.
> 
> Thanks for the info.
> 
> (As an amusing aside, I received a "We've missed you, Paul" canned 
e-

> mail from HP to my Verizon e-mail an hour after my post today 
> regarding their grey ink.  The products they had in their database 
> that I'd purchased are many years old, and I've not been on their e-
> mail list for year.  It's good to know they're listening.)
> 
> Paul
> www.PaulRoark.com
>

Yes. It often contains trace elements of metals and other chemicals
all dependent on the method of distillation. That's probably the
reason for the oem addition of things like EDTA in order to sequester
heavy metals.
They also use things such as a biocide and hydrogen peroxide to purify
the inks.

In a sense, it's easier for experimenters (like Paul) to come up with
suitable substitutes for oem formulations because we don't necessarily
need to worry about having things grow in our inks during long storage
as we can compound them at will and use them up fairly quickly. We can
also target specific needs and ignore the attributes we don't care
about, while oems have to target as broad an audience as possible and
need to care about how well their ink works with something like
recycled paper in a commercial environment.  Since we aren't in the
business of selling things, we also can take advantage of all that
very expensive research done by the oems. Seiko Epson alone has well
over 29,000 patents listed in the US. In the last 6 months there have
been more than 25 ink related patents that I've seen listed to them.
For the intellectually curious the patent databases are a virtual
paradise.

Regards
Duane




--- In DigitalBlackandWhiteThePrint@yahoogroups.com,
"steve_wadlington" <steve_wadlington@...> wrote:

> 
> An interesting note that I found in the past; "distilled water" that 
> we think is neutral PH can often be around 6.0 or so.