An alternative look at ink wetness

[amberleadavis]

I have to tell you, this thread has been fascinating and well, uh, a little over my head. 

 

[Sholom]

Seems to me that high surface tension should result in ink retraction into the nib, not the other way around, but this is assuming that how the ink wets the metal of the nib has no effect and I doubt that is true, or am I missing something? And once the ink has retracted up the nib, the paper can't have any effect until at least one paper fiber come into contact with the ink surface. Yes folks, this is complicated (but fascinating).

[dipper]

6 hours ago, Sholom said:

Seems to me that high surface tension should result in ink retraction into the nib

Before the nib tip touches down onto paper, if the nib tines are splayed outwards with gap at tip of nib slightly larger than at the base of the nib slit, then that is exactly what can happen.

 

Nib tuning experts generally advise that the nib slit gap should narrow towards the tip of the nib. (And you can see how capillary action will then draw the ink all the way to the nib tip.)

[amberleadavis]

 

I know you already know this, but here are two pens - with the same ink.  As you can see the vintage flex pen lays down a LOT more ink.

[InesF]

A small data update (three new inks, two of them from new-to-me Sailor inks) and a comment.

 

Here the data table (I have not measured electrical conductivity from them - my standard is empty, I have to order or make  a new one).

The Sailor inks are both of surprising high pH-value. Please be aware, pH around and above 9 is not very precisely measured with the glass probe I used. The high pH counters some of the effects of their (comparably) low surface tension.

 

As I have currently no more inks on my wish list, the next update may come in longer future.

 

Except! - the Ink Wetness Theory manuscript was yesterday accepted for publication. As soon as published (it needs layout, final spellcheck and proofread) I will post the link here. It will be published open access!

[LizEF]

5 hours ago, InesF said:

Except! - the Ink Wetness Theory manuscript was yesterday accepted for publication. As soon as published (it needs layout, final spellcheck and proofread) I will post the link here. It will be published open access!

👏 👏   Congratulations, @InesF! Very happy for you.

[txomsy]

Yep! It is a nice price for a well-thought out and carried out work.

[InesF]

22 hours ago, LizEF said:

👏 👏   Congratulations, @InesF! Very happy for you.

 

22 hours ago, txomsy said:

Yep! It is a nice price for a well-thought out and carried out work.

Thank you @LizEF and thank you @txomsy! Your comments during the measurement period had significantly contributed to keep my motivation high for completing the work and for publishing it!

[Lithium466]

Fascinating thread @InesF, thank you for your hard work! I look forward to reading your publication 👍

(it is that thread that pushed me to create an account)

 

Off topic, I was always curious as of why inks considered "safe" like Waterman serenity blue or Pelikan 4001 Royal Blue are in fact among the most acidic. Looks like modern FP don't care (although after years of using Lamy blue, my Lamy steel nib looks a bit tarnished).

Well I had that reversed, more like "why are they considered safe and everyday inks while they are in fact so acidic"?

 

[InesF]

On 5/11/2022 at 12:50 PM, Lithium466 said:

Fascinating thread @InesF, thank you for your hard work! I look forward to reading your publication 👍

(it is that thread that pushed me to create an account)

Hi @Lithium466, you are welcome! Thank you for your kind comment! The pleasure is all mine!

 

On 5/11/2022 at 12:50 PM, Lithium466 said:

Well I had that reversed, more like "why are they considered safe and everyday inks while they are in fact so acidic"?

Acidity and compatibility with modern steel nibs in no contradiction. Steel nibs of old (low carbon iron, not alloyed) were susceptible to corrosion, especially to iron gall inks with pH often below 1.

What you can observe on the surface of modern nibs after years of use is more often a precipitation than a surface corrosion. It's like limescale in the sink. If you can separate the metal nib from the feed, you may either use a soft cleaning powder (household quality) for mechanical or boiling diluted vinegar for chemical removal. But be aware: never apply those to the feed or to other parts of the pen body!

 

I used a Waterman Maestro fountain pen with gold plated steel nib with Waterman Serenity Blue (pH 1.9) for roughly 25 years non stop (with a cleaning every 5  years, or so). The gold plating has suffered during this time, nothing else happened to the nib.

 

However, such deposits as you observed may look disturbing but will not reduce the writing quality significantly. By chance, the deposit may change the surface wetability of the nib in a positive way.

 

Use you pen with joy and don't worry too much!  

[Lithium466]

Good advice!

However, after years of using "Times New Roman in a bottle" (as one reviewer said, unfortunately I read so many reviews lately I forgot who) I feel like trying something else, and your work will be a precious help in my choice (I'll probably poke at some extremes to establish testing & selection).

 

I do have some 60/70's Waterman bottles, and very cheap steel nibs and dip pens from that era...and none are corroded. I feel there is more than just PH  

(also these nibs are of such soft steel that they we're probably thrown away because of wear before corrosion)

[InesF]

14 hours ago, Lithium466 said:

Good advice!

However, after years of using "Times New Roman in a bottle" (as one reviewer said, unfortunately I read so many reviews lately I forgot who) I feel like trying something else, and your work will be a precious help in my choice (I'll probably poke at some extremes to establish testing & selection).

@Lithium466, you are welcome!

Unfortunately we can't predict the properties of an untested ink only by brand or colour - at least not always. Among the ca. 2200 tested/reviewed inks only a minority is measured so far.

 

14 hours ago, Lithium466 said:

I feel there is more than just PH  

Indeed, it is!

pH of an ink is not a critical property (as long as it is not among the extreme ends of the scale). It is much more important for mixing two ore more non-permanent inks: widely different pH, especially when above and below neutral (7) can cause strange effects of the mixture. Mix permanent (or waterproof) inks only in small portions and days in advance before filling them into a fountain pen.

 

Have fun with the colourful side of handwriting!

[InesF]

As I couldn't resist to buy two more inks (...ach!...), there is a table update. Meanwhile I have made new calibration liquid for the conductivity meter and measured the new and the three inks from last shopping tour.

78 inks are enough to last for a lifetime. In addition to my fountain pen shopping moratorium (which I already broke), I declare a new ink shopping moratorium!

(at least until summertime ...)

[LizEF]

4 hours ago, InesF said:

I declare a new ink shopping moratorium!

 

4 hours ago, InesF said:

(at least until summertime ...)

Phew!

[dipper]

12 hours ago, InesF said:

78 inks are enough

...... to show that each ink brand has a tendency to cluster in its own part of the list.

 

When you had fewer inks tested the variations from named ink to named ink dominated. But now with 78 inks the broad differences from maker to maker are becoming visible.

 

Wet DeAtramentis?

Middle of the road Pelikans?

Dry Watermans?

And odd outliers such as two wet Watermans tamed with Gum Arabic.

 

I am surveying the various ink makers by visually scanning up and down the list - not a great way to do statistical analysis!

If available as an Excel .xlsx file I would be itching to fire-up some Excel cluster charts, maker by maker.

 

 

[InesF]

On 6/6/2022 at 6:28 PM, LizEF said:

 

On 6/6/2022 at 2:09 PM, InesF said:

(at least until summertime ...)

Phew!

[mtcn77]

On 6/6/2022 at 3:09 PM, InesF said:

As I couldn't resist to buy two more inks (...ach!...), there is a table update. Meanwhile I have made new calibration liquid for the conductivity meter and measured the new and the three inks from last shopping tour.

78 inks are enough to last for a lifetime. In addition to my fountain pen shopping moratorium (which I already broke), I declare a new ink shopping moratorium!

(at least until summertime ...)

I keep citing your great work, @InesF! Much obliged!

[mtcn77]

I found some interesting physics explanation. It says that capillary action is correlated positively with the decrease in surface tension and inversely with the density of the liquid, ink in our case.

So, where would viscosity fit into the frame?

I couldn't find any direct links between viscosity and capillary action, if anything it says they are independent from each other. Hence, it becomes possible to have inks that flow well due to low surface tension, but not laying a lot of ink due to high viscosity. At least that is what I make of it.

[dipper]

57 minutes ago, mtcn77 said:

So, where would viscosity fit into the frame?

 

Surface tension is a force. Unbalanced forces cause movement (of ink etc), until forces become balanced.

 

Viscosity is not a single value of force. It is a property of a fluid that defines how much force is created inside the fluid when one part of the fluid slides over another part. If the sliding flow stops then the viscous forces disappear. Viscous forces always act in directions to oppose the sliding movements.

 

Putting the two together...

 

If surface tension forces act to move ink through channels in a pen feed or nib, or out onto paper, or even into the paper, then - in theory - that flow and sliding and soaking-in movement will be opposed, resisted, slowed, by viscous forces.

 

The research project by @InesF did find some measurable links between aspects of "wetness" and ink viscosities. It is a bit complicated though, because it involves what the ink does on the paper after leaving the pen nib. I am looking forward to the forthcoming published scientific paper to read how Ines describes the conclusions about viscosity.

[mtcn77]

Well, to complicate matters further, the differences can be elucidated if we compare oil and water: water has more surface tension than oil, but oil always flows slower(I think) since it has higher viscosity.

I made this point since capillary action formula involves surface tension and density, but not viscosity. Also, oils might have lower density than water - I just can't absorb how viscosity is excluded from the equation when oil is less flowy.