Is Noodlers Black pigmented or dye-based?

[LizEF]

3 hours ago, TSherbs said:

Awesome, thanks Liz. 

You're very welcome.

[dipper]

Continuing the line of enquiry suggested by @BrassRatt .... Can pigment particles be seen under a microscope? ....

 

First test (images posted above) established that for a non-nano black "calligraphy" ink the black particles are clearly visible at 100x magnification. Particle size was estimated to range from 7 micron down to 0.7 micron. There may be even smaller particles present in that ink, but not visible at 400x magnification.

 

Today's test looks at a modern "nano" size black pigment ink, Sailor Kiwaguro. The smaller particles in this ink are so very small that this ink is safe for use in fountain pens.

Question... Are the nano particles visible?

Answer... No! But....(?)

 

I pushed my microscope to its limit - 40x objective and 15x eyepiece = 600x magnification. Viewing various thicknesses of wet ink under a cover-slip, all that I saw was a featureless haze.

 

Viewing deeper layers the transmitted light does not go darker to black (as seen with the larger particle pigment). Instead, this ink is seen as a golden red/brown in transmitted light. Fading to deep brown, and then eventually black when the ink layer is too deep for any detectable light to penetrate.

 

This is not only like a sunset, I suspect it is caused by the same process as a sunset.

Ultra small particles (smog) and water molecules etc in the earth's atmosphere scatter blue light, and transmit the red light. The same appears to be happening in the ink, when in its liquid form.

 

Here is a view at 100x magnification. (I can't record a decent phone camera image at higher magnifications.)

A thin layer here. Ink was wicked out from under the cover-slip using a paper towel touched to the edge of the slip, until the ink film thinned and became translucent.

Air bubbles included as evidence the image is in focus!

No red sunset effect here as the ink layer is thin, and there is a blue filter rotated into the microscope's light condenser device.

 

But ..... The results above do not mean that you will never see black spots in this ink.

Here is a layer of Kiwaguro applied to a glass slide, no cover slip used, and allowed to air dry.

 

What on earth is that?!!

 

It seems that the invisibly small nano particles can clump together during the drying process, when drying as a thin film on glass.

 

These clumps do not appear when the ink is on paper. It dries to a continuous black coating, entirely covering the paper fibres.

 

I tried and failed to record the drying process on paper. The slightest swelling of the paper sends the image way out of focus.

 

Here is a timelapse video of the ink drying on glass. 60x actual speed, because only slightly more interesting than paint drying....

The image above is not out of focus. Note the sharp edged gaps and bits of dust(?) on top of the ink.

The black blobs are fuzzy edged because they really do look like that.

Bazillions of nano-size particles crowding together creating the dark blobs with fuzzy edges.

[TSherbs]

So, at 600x magnification, still no visible individual particles in suspension of a nano-particle pigmented ink. That's interesting. 

[amberleadavis]

I'm still stuck on Mordant. 

(especially of humor) having or showing a sharp or critical quality; biting.

[dipper]

14 minutes ago, TSherbs said:

So, at 600x magnification, still no visible individual particles in suspension of a nano-particle pigmented ink.

... and so we cannot use an optical light microscope to view a fountain pen ink to determine if it is dye-based or pigment based.

 

We can observe particles in non- fountain pen inks. (Calligraphy inks, Sumi stick ink.) Those particles are easily visible at 100x magnification in the wet ink.

 

And we have to be aware that it is possible for specks to appear during the drying process, (or maybe during the cellulose reacting process?).

So microscope evidence needs to be interpreted with such possibilities in mind.

 

Optical microscopes can go up to 1000x magnification with special "oil immersion" objective lenses. So there is a slight chance remaining that some nano pigments might just be visible at that magnification.

We really need access to a scanning electron microscope 😀.

[amberleadavis]

You are all so amazing. Thank you for the hard work and images!

[LizEF]

11 minutes ago, dipper said:

We really need access to a scanning electron microscope 😀.

[arcfide]

I feel like new fountain pen users should see a sign in these threads along the lines of, "Warning, Severe Ink Geekery present, proceed at your own Nerdom." But I love it. This is good stuff. 

[TSherbs]

10 hours ago, amberleadavis said:

You are all so amazing. Thank you for the hard work and images!

 

repeat

[TSherbs]

I asked the same question over on Reddit to crowdsource there too. The question got down voted, as did Liz and I specifically . The most popular responses there were the ones quoting the Jet Pens descriptor most likely written from what Noodler's provided them. Another person speculated that Noodler's black could well have both dye and pigment materials. Maybe the phrase "dye based" actually allows for the possibility that a secondary (and lesser) pigment component can be added to the mixture.

 

At any rate, what I surmise from the awesome efforts here is that neither Liz nor dipper could replicate with a light microscope what homer described as seeing particles suspended in a clear carrier.

 

Some geeky insights gained, but the quest continues.

[yazeh]

@dipper amazing. Thanks!

[dipper]

Here is a link to "Horiba", a manufacturer of equipment used to measure pigment particle sizes in paints, cosmetics, and in INKS......

 

https://www.horiba.com/int/scientific/applications/chemistry/pages/pigment-powder-coating-and-ink-particle-size/

Mid way down that page is a link to download a pdf paper titled "Particle Size Analysis of Inks".

 

The ink particle sizes mentioned make it clear why we cannot see "nano" fountain pen ink pigment particles with an optical microscope.

 

As estimated recently, with a microscope I can barely detect particles around 700 nanometres (=0.7 micron) size. At 400x magnification they are tiny specs on the edge of visibility. A better quality optical microscope and camera could see particles a fair bit smaller than 700 nanometres.

 

But, quoting from the pdf paper mentioned above, "Most ink pigments fall into the range of 50-200 nm."

And that "most" may be referring to printing inks and inkjet printer inks in general, not our niche product nano fountain pen inks.

[dipper]

I entered some choices into the Horiba web page linked above, imagining that I was an ink manufacturer wanting to measure particle sizes in supplies purchased, and in my batches of ink sent out.

 

This is what Horiba recommend to me.  A neat little product....

 

 

https://www.horiba.com/int/scientific/products/detail/action/show/Product/nanopartica-sz-100v2-series-1945/

[TSherbs]

very cool:

Quote

Particle Size Measurement Range 0.3 nm to 10 µm

The SZ-100V2 Series measures particle size and particle distribution width by dynamic light scattering (DLS).
Analysis across a wide range of sample concentrations: Measurement of samples ranging from low ppm-order concentrations to high-concentration samples in double-digit percentages is possible. Accepts commercially available sampling cells. Analysis of small-volume samples is also possible.

 

[Arkanabar]

28 minutes ago, dipper said:

<snip>

As estimated recently, with a microscope I can barely detect particles around 700 nanometres (=0.7 micron) size. At 400x magnification they are tiny specs on the edge of visibility. A better quality optical microscope and camera could see particles a fair bit smaller than 700 nanometres.<snip>

Um, probably not.  Visible light wavelengths vary from about 380-750nm, so, it's not very helpful for things much smaller than that.  The Wicked Paedia's current article on optical microscopy suggests the limits of resolution is particles of at least 200nm in size.

[LizEF]

Thank you, @dipper!   You have saved me from breaking out the oil in vain.  I shall proceed with diluted Noodler's Black, but I think we've confirmed that anyone who thinks they're seeing particles under an ordinary microscope is likely seeing clumps of something - whether dye or pigment or other ingredients.

[AceNinja]

On 3/18/2023 at 8:55 AM, dipper said:

Here is a link to "Horiba", a manufacturer of equipment used to measure pigment particle sizes in paints, cosmetics, and in INKS......

Not related to the topic.  But, if I read the company name a bit too fast, it becomes 'horrible' ...  who make up the name for that company?  🤣

[XYZZY]

I was just reading about nib creep on Richard Binder's site (http://www.richardspens.com/ref/ttp/creeps.htm) and ran across a statement that reminded me of this thread.  Apparently he has known the answer to this question for ages.  Emphasis added by me:

 

Quote

Not so well known for their extreme wetness are Noodler’s “bulletproof” inks. It turns out that these inks are really really wet. Unlike ordinary fountain pen inks, they are not perfect solutions; their coloring agents (dyes) are dissolved, but the component that causes the ink to bond permanently to the cellulose in paper is suspended particulate matter. It’s very fine, but inks containing particulates of any type must also contain a greater amount of surfactant than other inks to keep from clogging the narrow fissures in a pen’s feed.

 

[LizEF]

13 minutes ago, XYZZY said:

I was just reading about nib creep on Richard Binder's site (http://www.richardspens.com/ref/ttp/creeps.htm) and ran across a statement that reminded me of this thread.  Apparently he has known the answer to this question for ages.  Emphasis added by me:

Thank you!

[yazeh]

@XYZZY thanks a lot! Very clear and helpful 👍