An alternative look at ink wetness

[arcfide]

It's not at all surprising to me that paper is the primary consideration if you want to concern yourself with wet appearance on the page, because that appearance comes not from the amount of ink the page, but the amount of ink that is not absorbed into the paper immediately. The rest is probably just a matter of how much ink gets onto the page, and how it spreads, rather than how much it glistens. The only factor I can imagine on top of that would be that a heavier application of ink on paper that is somewhere in the middle in terms of ink resistance will absorb into the paper noticeably slower than less ink, and will thus appear to glisten for a longer period of time than a fine line on the same paper, but once you get to the point where the paper is resisting ink for a long period of time, then the glisten factor won't change between lots of ink and a little bit of ink on the page. 

[txomsy]

A note of dissent: not all FP paper is coated. It is the porousness of the paper that makes it misbehave by increasing the surface. Coating reduced that surface, granted, but so does appropriate pressing.

 

I still keep old (30-50 years old) paper that is non-coated and fully FP friendly. Ragged and all. The difference is it is more tightly pressed and thus there is little space for ink to spread into.

 

The following picture is from some quickly scribbled annotation with an F or EF nib to an "article" we were writing dating from the late '80s (I confess I do not know how or why do I still keep this around). The faded computer text is printed with a dot-matrix printer in cheap "printer paper" of the times, in Monaco 9 most likely, which comes to show its age. The paper is, obviously aged and yellowish. There are no signs of ink spread, bleed-through, blemishes, etc...

 

The point is: do not let your bad experiences with modern, ultra-low quality and ultra-cheap for maximum profitability paper blind you or your perceptions.

 

Marketing will make you believe that better is not possible or terribly expensive, because that way they won't have to produce alternative lines, and can force a one-size-fits-all into everybody, whether it fits them or not (and if not, force people to accept their maximum profit product, like it or not).

 

FP-friendly paper was the standard until recently (in my case, I started having problems with cheap printer paper only some three years ago, and now it is becoming worse every time I buy new printer paper). I can still find FP-friendly notebook paper easily on abundant B&M shops. Coated or not.

 

YMMV, but do not believe the world is limited to your experience or to what marketing wants you to believe.

 

[InesF]

Hi Sholom.

Thank you - that's an excellent summary!

In fact, I did the research to learn about inks and therefore to stop guessing how and why a particular ink behaves.

While my (still ongoing) measurements brought already some insights, there are new questions arising. And one has to do with contact angel (or wettability) of the metal alloy of the nib tip. That's one of the parameters I can't measure and, I'm sure, has some effect on ink delivery of a certain fountain pen brand / nib brand.

 

New measurements are in the pipe - stay tuned, some more entertainment is to be expected...

[arcfide]

12 hours ago, txomsy said:

A note of dissent: not all FP paper is coated. It is the porousness of the paper that makes it misbehave by increasing the surface. Coating reduced that surface, granted, but so does appropriate pressing.

 

I think most people in the FP world on forums that I have seen incorrectly use the term "coated". Most of the paper that I have seen that is regarded as FP-friendly is *not* coated, but simply sized, pressed, or otherwise treated/mixed with the appropriate fillers to reduce ink absorbency. In fact, Pilot has or did have an entry in their FAQ talking about how coated paper is often *not* appropriate for use with fountain pens. 

 

I'm not sure who's opinion here you're speaking against with regards to expanding worldviews or listening or not listening to marketing? It's also helpful to define what FP friendly means. For example, Fountain Pen Love's website would generally require that fountain pen friendly paper should be scored on its ability to show shading and sheen, and I think most people tend to judge a paper based on this. Many papers that are traditionally available are *not* good at showing sheen or shading, even if they do not exhibit bleedthrough or feathering. Does that make them not FP-friendly? To some people, yes. 

 

Paper making hasn't changed that much over the past decades, and while people use the term "coated" to refer to the feeling of the paper, I think we generally recognize that it's an incorrect use of the term when referring to the technical construction of paper. Technically speaking, most writing paper is uncoated. I'm not sure that comes as a surprise to anyone? 

 

Additionally, it's fairly easy to find reasonably fountain pen friendly paper (no bleed, feathering) at very inexpensive rates in large reams, with plenty of different surface textures to suit. I don't think anyone is surprised or arguing about this either. Companies just don't advertise such paper as being "writing paper" anymore because that's not what the market demands.

 

So, I'm not sure what perception you are arguing against in your post above. 

[InesF]

On 6/9/2021 at 2:33 AM, arcfide said:

It's not at all surprising to me that paper is the primary consideration if you want to concern yourself with wet appearance on the page, because that appearance comes not from the amount of ink the page, but the amount of ink that is not absorbed into the paper immediately. The rest is probably just a matter of how much ink gets onto the page, and how it spreads, rather than how much it glistens. The only factor I can imagine on top of that would be that a heavier application of ink on paper that is somewhere in the middle in terms of ink resistance will absorb into the paper noticeably slower than less ink, and will thus appear to glisten for a longer period of time than a fine line on the same paper, but once you get to the point where the paper is resisting ink for a long period of time, then the glisten factor won't change between lots of ink and a little bit of ink on the page. 

arcfide, that's high quality thoughts.

I'm still questioning why two nibs with almost the same tip diameter lay down different amounts of ink on the same paper and both are not ink flow limited.

I take any help I can get - I really like to bring light to this behaviour.

[arcfide]

1 minute ago, InesF said:

arcfide, that's high quality thoughts.

I'm still questioning why two nibs with almost the same tip diameter lay down different amounts of ink on the same paper and both are not ink flow limited.

I take any help I can get - I really like to bring light to this behaviour.

 

Have you confirmed that the tine spacing on both nibs is the same and that the nibs are not just not flow limited, but also have the same flow rate? 

[txomsy]

On 6/8/2021 at 11:59 PM, Sholom said:

Given the wide range of paper coatings (yes fountain pen-friendly paper is coated–just try writing on filter paper to see what effect the paper coating has), interfacial tension could explain some observed differences between what people report for ink behaviour with the same ink and similar nibs.

Er... this?

 

I would venture to say that "FP-firendliness" is a "Humpty-Dumpty" definition.

 

Quote

“Must a name mean something?” Alice asks Humpty Dumpty, only to get this answer: “When I use a word… it means just what I choose it to mean – neither more nor less.”

 

As for "facts", I do not think a nib or an ink has any special knowledge of (or want for) "paper". That implies that the nib will just lay out ink, and that the ink will simply spread over a surface --or fly on air after a shake, or maybe spread on other fluids if the nib is submerged in a hydrophilic liquid (and even on hydrophobic fluids depending on relative surface tensions)...--.

 

So, the talk should be about surfaces.

 

A surface made of loose knitted fibers will be more or less "ink friendly" depending on the nature of the fibers: Very absorbent fibers will simply capture the ink and not allow it to spread, not so much absorbent will allow ink to flow in the spaces between fibers.

 

A surface made of tightly knit fibers, will simply reduce the likelihood of ink getting in between spaces, which may also be bad if the fiber is not absorbent for then the ink will spread over the surface and extend farther than if there was space to take it, it may not have bleed-through but may have feathering (or not, but then may lay out wider lines).

 

It may be amphipathic, or a mixture of fibers, and then show weird, unexpected combinations of behaviors...

 

Same for coatings:

 

A hydrophobic coating may work wonders on wax-/hydrophobic- based inks like many inkjet inks, but with water-soluble inks, it will repel the fluid and that may result (depending on coating surface and composition) in feathering, spreading or maybe just on the ink not spreading but taking forever to dry, and then smearing afterwards.

 

A hydrophilic coating may result in ink being absorbed and, depending again on the properties of the coating, it staying and drying quickly or it staying but spreading. For a hydrophilic coating much of the result will depend also on the underlying material: if the substrate is hydrophobic it will detain ink and avoid bleed-through, but might lead to spreading or feathering, if it is not hydrophobic it will depend on how closely knit and its properties...

 

Bottom line: it is all physics. Coated or not, closely knit or not, one material or the other, none is by itself a sure recipe.

 

Want a recipe? Write. Try many surfaces. Touch and handle them. Your brain is a neural network, with enough data it will end up learning what works and what doesn't, for your own definition of "working".

 

The thing about marketing?

 

I publicly confess my ignorance on the matter. I'm only talking of wild, uneducated deductions from what I hear here from people in the US and what I see with reams of loose paper in my own vicinity.

 

Locally I see a huge amount of SME's and small B&M shops carrying many varieties and qualities of bound paper, but it is becoming ever more difficult to find good loose paper, as most production is "diverted" towards inkjet-printing, and when I look at makers' websites I find non-printer paper become more scarce each day, with some historic brands of quality hand-writing paper totally disappearing.

 

From the US, I get the -likely wrong- feeling that most people there have difficulty finding SMEs, small B&M shops or makers, and having to resort to major chains, which only carry cheap paper in a very limited variety, and use it even for bound goods, because that is what sells the most and gives them the larger margins. Not that it is their fault: they have investors that demand larger margins every year and have to concentrate only on what gives them these larger margins, want it or not. So, they will also tell you the few brands they favor are the best thing after sliced bread to justify their limited offer, and try to induce you to accept what they need you to buy for them to survive.

 

Again, that's nothing "diabolic" or "angelical", it is pure "physics" of modern (stock-market) economy.

 

But just as they will try to make you buy what is in their best interest, you have the option to buy what (and where) it is in your best interest.

 

One just needs to know what's better for oneself, and that's the reason of this thread.

[InesF]

3 hours ago, arcfide said:

 

Have you confirmed that the tine spacing on both nibs is the same and that the nibs are not just not flow limited, but also have the same flow rate? 

arcfide,

to my understanding, flow limitation and having a certain flow rate ist, by the effect, the same. If the geometry of a feed/nib/tip allows a certain flow, you may call it limited at this certain flow.

 

When I, experimentally, draw lines with two different feed/nib/tip fountain pens and I checked beforehand their maximum flow (with was ca. 14 g ink / km line) and than draw lines on non-absorbent paper and one lays down ca. 4 g /km while the other lays down ca. 6 g /km, no pen is under any form of flow limit but they deliver different amounts on the same paper.

 

I received my USB microscope with todays post delivery and will do some (hopefully precise) line width measurements - hopefully, enabling a new calculation of ink delivery per paper surface area. Measurements will start at weekend.

[InesF]

3 hours ago, txomsy said:

But just as they will try to make you buy what is in their best interest, you have the option to buy what (and where) it is in your best interest.

wise words!

[InesF]

At first a new method:

Ink line width measurement was done with a Conrad USB microscope. It was fixed at a stand, positioned to be best possible parallel to the ink lines and set to maximum magnification. From each line drawing sheet one photo was taken at a position near the centre of the line drawings. Measurement calibration was done on the square grid letter pad paper – the 5 mm grid was assumed to be a 5.00mm grid and was represented by a distance of 400 or 401 pixel vertically and horizontally. Line width measurement was done by drawing a selection rectangle in Gimp, so that the ink line edges were visually matched by the rectangle lines. Gimp shows the selection rectangle size in pixel. These pixel widths were calculated back into mm.

 

 

The composite image shows one paper type per image row and one ink type per image line. The Waterman Mystical Blue (bottom row) has a high surface tension and resulted in more narrow and less spreading lines. The two deAtramentis Aubergine inks (top image line original and second image line with Gum Arabic added) behaved almost exactly the same, although the Gum Arabic increased its viscosity dramatically. All ink properties and the exact ink consumption data are shown in the results table (below).

The hp inkjet photo paper had the most intense looking ink colors, always had the highest ink consumption and the broadest lines but the lines had perfectly sharp edges with zero feathering or spreading. However, the inkjet photo paper makes handwriting with a fountain pen ... somehow inconvenient.

 

New results:

The results table is now extended with ink consumption per m² and I had measured some more inks of my collection for surface tension and viscosity. When comparing with previous uploads you may recognize some minor differences. This is because I extended the calibration with more reference measurements which are now included in the calibration formula.

 

 

Meanwhile there are enough data for some preliminary graphical data presentations:

 

The top two diagrams are drawn with data measured with the Waterman Perspective (M) fountain pen, the bottom diagrams with data from the Cross Botanica (M) pen. The left diagrams show correlation calculations for ink consumption in g ink per km line length (for all three paper types), the right diagrams show ink consumption in g ink per m² (calculated for two paper types).

All ink consumption correlations are inverse proportional to the inks surface tension, more strict for absorbent and non-absorbent papers and less strict for the photo paper. The ink consumptions per area have a bit steeper correlations with surface tension, which makes this parameter a bit more sensitive than the ink consumption per line length. However, both correlations follow the same causality or causalities.

 

Finally, the next two diagrams show the correlation between line width and ink surface tension (left) and ink viscosity (right). Those diagrams are a bit tricky to interpret: both of the ink properties influence how the released ink will distribute on the paper, ink consumption is dependent on both of them.

EDIT: Oh, sorry! The dependency of ink line width on viscosity ist an artefact  The high viscosity inks are those with very low surface tension, I had added Gum Arabic to them. So these are still more influenced by the surface tension than by viscosity!

 

These first evaluation data should not be over-interpreted! After measuring the consumption of some more inks, the first principal component analysis may become reliable and may provide more insight.

 

Next update is to be expected in two weeks.

[7is]

Beautiful and helpful! Thank you!

[PuliMorgan]

Can't stop admiring the design of the experiment and the precise technical language in which the data and conclusions are presented.

 

This year's IgNobel Prize goes to.....

[InesF]

Thank you 7is!

Thank you PuliMorgan!

 

Meanwhile I have found the publication about hydrodynamics of ink flow in the Physics Review Letters from 2011. That is superior science.

However, what drives me is the daily routine practical aspect of writing with pen and ink. I do write with fountain pens intentionally and exclusively now since almost 50 years and never before questioned how it works (and how it fails).

 

Simply said: the time is now!

[Sholom]

Completely agree with txomsy. What I meant by coated includes sizing since that is effectively applying a coating to individual cellulose fibers. There are other types of paper processing that can also make paper more fountain pen friendly, as he mentioned. I'm sure that the type of sizing matters a great deal. Again, this is a fascinating study and I thank InesF and the other commentators for their insights. Ultimately, I think we have to view nib, feed, ink, and paper as a system and changing the material contents of any of them creates a new system with somewhat different behaviors.

 

As a side note, I would be careful about adding gum arabic to inks, not because of any chemical reaction risks but just in terms of being able to clean the ink out of the pen. As long as the ink hasn't dried in the pen there should be no problem, but gum arabic can be rather slow to redissolve if it gets completely dry (which enables some interesting effects in watercolor paintings)

[InesF]

On 6/15/2021 at 8:01 PM, Sholom said:

Completely agree with txomsy. What I meant by coated includes sizing since that is effectively applying a coating to individual cellulose fibers. There are other types of paper processing that can also make paper more fountain pen friendly, as he mentioned. I'm sure that the type of sizing matters a great deal. Again, this is a fascinating study and I thank InesF and the other commentators for their insights. Ultimately, I think we have to view nib, feed, ink, and paper as a system and changing the material contents of any of them creates a new system with somewhat different behaviors.

 

As a side note, I would be careful about adding gum arabic to inks, not because of any chemical reaction risks but just in terms of being able to clean the ink out of the pen. As long as the ink hasn't dried in the pen there should be no problem, but gum arabic can be rather slow to redissolve if it gets completely dry (which enables some interesting effects in watercolor paintings)

Thank you!

 

You are totally right. Writing with fountain pens and ink on paper is a complex thing of many parameters. Luckily, physics is in most cases with us, so that it can be as simple as pull a cap and start writing.

 

Yes and no about GA. Indeed, Gum Arabic can be nasty when a full cartridge/converter/body fill dries through the nib. However, even when a sucking for a full month is necessary, it will dissolve eventually.

This will not happen with inks based on shellac, protein glue or acrylics.

 

I use Gum Arabic since many years for lettering and calligraphy with normal fountain pen ink in dip nibs. But I use it also quite frequently for fills in fountain pens to tame those nasty-low-surface-tension inks that like to feather and spread like crazy. And yes, so far I never forgot a filled fountain pen for longer than one month.

[InesF]

Let's start with a new method: Measurement of pH-value. An older instrument (ORI, Ing. Otto Riefle, type 2C 18 11) was used with a pH probe (glass electrode with Ag/AgCl reference electrode; type HPT 88435), calibrated with pH4 and pH7 reference buffer. Unfortunately no pH10 buffer was available.

 

 

The new data table contains all measured results done so far with the inks in ascending order of brand and color name. It has now listed all my inks (three more ordered, not arrived yet).

Compared to earlier reports I have skipped the data columns for hp inkjet photo paper as they do not provide any new insight (compare with the diagrams about ink consumption per km). I decided to skip the consumption measurement on photo paper for upcoming measurements. pH-values of some inks surprised me a lot, as there are some strongly acidic and two alkaline, namely Iroshizuku Yama-budo and Pelikan Edelstein Ruby.

If not searching for a specific ink, the following table with the inks ordered in ascending surface tension may be helpful to find the better fitting for a certain nib. The low surface tension inks tend to do better with EF or F nib sizes while the high surface tension inks may look pale (or dry) in such fine nibs but do better with M, B or stub nibs. The inks with surface tension between 50 and 60 mN/m still need to be tested individually with try and error.

 

 

In this second table I have colored the pH-values by category, with white for neutral (or close to neutral), pale blue for alkaline, pale red for slightly acidic and a darker red for strongly acidic. While there is no general rule about ink mixing, you may consider unexpected results when mixing strongly acidic with alkaline inks. I have not done systematic trials, but in the past I have mixed Waterman Serenity Blue (pH 1.9) with Pelikan 4001 Black (pH 7.1) and was happy with the color - only to see the color fading away within ca. 8 years in the dark, while neither of the single inks faded in such a short time.

 

Finally some diagrams for ink consumption on three different papers, first for the Waterman Perspective M and below for the Cross Botanica M fountain pen.

 

 

There are no big surprises. With all the measurement errors summing up, the correlation coefficients are far from perfect but in acceptable range for the absorbent notepad paper, they are worse for the 'good' Kyome letter pad paper (a small surprise) and a correlation is almost non-existent for the hp inkjet photo paper. The latest is the most obvious, as the photo paper is not a real paper, it is more a structured surface on top of a carrier sheet. The cavities have a certain capacity and if they are full, they are full. Variation is possible only if the line width varies as well (it did only rarely). Although writing with a fountain pen on such a photo paper is not among the most pleasant things to do with a fountain pen, the paper brings out the best color impression for each ink - it may be great for making these ink swatch cards.

 

The new data did not change the general conclusions. The influence of the pH-value on the inks behavior is not known so far - if there is a pH sensitivity of a paper or of its coating, it may be.

 

I will continue with the ink consumption measurements; next update is to be expected next weekend and afterwards I will try a first draft of a principal component statistics.

[LizEF]

3 hours ago, InesF said:

I have not done systematic trials, but in the past I have mixed Waterman Serenity Blue (pH 1.9) with Pelikan 4001 Black (pH 7.1) and was happy with the color - only to see the color fading away within ca. 8 years in the dark, while neither of the single inks faded in such a short time.

While your entire post is of great interest, this was something that stood out to me.  As you say, it's not enough to be conclusive on it's own, but it is enough to make one wonder.  Instinctively, it makes sense, and I would say it's a data point worth including when newbies ask about the risks of ink mixing - and it's one I haven't seen mentioned before.

[Frank C]

Thank you for sharing all this work. I do find the range of pH values interesting. I guess that fountain pens are able to tolerate these strongly acidic or basic inks. 

[samasry]

Very good  study.   It is becoming more and more  clear  to me that paper is the weakest link in the entire  fountain pen writing chain.  It is the  hardest to study and the paper manufacturing vector is hardest to sway.

[InesF]

18 hours ago, LizEF said:

While your entire post is of great interest, this was something that stood out to me.  As you say, it's not enough to be conclusive on it's own, but it is enough to make one wonder.  Instinctively, it makes sense, and I would say it's a data point worth including when newbies ask about the risks of ink mixing - and it's one I haven't seen mentioned before.

Thank you, Liz.

Indeed, many inks mix well together, there are only a few that form precipitates or do other strange things in due time.

I wrote about 5 years with a Waterman Blue / Pelikan Black mixture without any problem, except for the fading which I recognised a bit later. I'm still mixing Waterman Blue and Waterman Green (both acidic) as I did since meanwhile ca. 25 years and there is no problem at all. Also my mix of Pelikan 4001 Blue (2.2) with deAtramentis Ruby Red (5.1) seems to have no problem since ca. 5-6 years on paper.

 

Mountain of ink lists currently 1524 ink reviews - I guess, there is some room for surprises! If I think on all permutations of two ink mixtures or, god beware, when I think of mixtures of three inks, it makes me slightly dizzy.🤫

 

What about a combined lecture series about all these aspects of fountain pens, inks and papers as a part of a pen show? I mean, with announcement and a special dedication for beginners. What's your opinion, can this be something interesting for a show organiser?