Standardizing the Wetness of Pens

[nkk]

I have decided I want to standardize the wetness of a fountain pen. Before I get to that, a little background:

 

I am currently a student of Chemical Engineering and Physics. My whole life is based around standardization, experimental methods, derivations of governing formulae and equations for experimentally observed events, etc. Not only that, buy my whole personality tends toward standardization.* Thus, it has always annoyed me that people will state that pen X is wet, whereas someone else will say it is just right. Or that two people can use the same pen, and one will say it is bone dry, and the other will insist it is gushing too much ink to make the desired line width. I have been annoyed enough by this, and I plan to standardize it. I do not expect everyone to adhere to my standard--in fact, I think very few will. However, I want there to be one.

 

Now, on to the derivation. I am still working this out and determing all the variables that will alter the wetness (i.e. flow) of a pen. So far, I have:

 

• Atmospheric pressure, which may be reduced to dimensionless correction term for downward force. I am hoping that at real the standard atmospheric pressure (1 atm), the correction factor will make this term in the equation equal to 1.
   
  
• Humidity term. I first need to research the effects of humidity on capillary action with water, and other things it may change. More to come on this bullet point.
   
  
• Reduced area of the nib. This is the area of the line produced divided by the area of the nib. It, too, will be a correction term in the equation. It will be used to correct for nibs that are wide enough to be BBB, but so dry they write as an M. Thus, the term will be <1, and will reduce the wetness of the nib. On the same note, nibs that output so much ink that it cannot help but flow and be wider than the actual nib (think a nib with a constant stream of ink running down, with not feed to stop gravity from just letting everything flow) will have a reduced area >1, which will correct their wetness. Ideally this term will always be 1, but as Mr. Binder's site in many of the articles, this is rarely the case.
   
  
• The area of the nib. This term will be used in the reduced area above, but will also be used by itself. It is pretty self explanatory. Here I am referring to the writing surface area
   
  
• The amount of ink put down in a stroke. I still do not know how I will measure this.
   
  
• Viscosity of ink. I am pretty sure I want to standardize this, though
   
  
• Pen weight/writing pressure. See the next to last bullet below under standards to see why
  

 

And now, the things that will alter the wetness, but which I am holding constant for standardization purposes:

 

• Type of paper. To reduce bleeding that will change the reduced area, I will use Crane's 100% cotton paper.
   
  
• Type of ink. Each ink will have a different viscosity. I will probably use Waterman BB or some otherwise easy to get and cheap ink. The other option is to use water, but that will be harder to measure the line width of.
   
  
• Pressure used to write. I am thinking that I should not standardize this as a set number, but since we all say let the pen rest on its own weight, then it would be wise to just say that whatever the pressure the pen puts on the nib. Of course, this will have to be evaluated at a full ink tank, with manufacturer's converter, etc. This may have to change, though, to a standard pressure for all pens.
   
  
• Speed the pen was written with to make the lines. If you write faster, it skips, and that will alter the results. I am thinking I will just write at a somewhat slow speed for 10 seconds, see how far I got, and take the average over about 10 trials. That should be a good speed for skipping to not occur on any pen.
   
  

 

So, does anyone have any comments, additions to either list, or other useful advice? This will probably take a couple of months, as I have schoolwork which has priority, but I do want to do this, if not only to say I did.

 

-Nkk

 

*An aside for your amusement: I spend 12 weeks over the summer for the summer semester of classes, to get some requirements out of the way. Every one of those days, I went to the same restaurant. I ordered the same thing, and paid the exact same amount. I sat in the same chair, facing the same direction, at the same table, every day. My backpack was put in the same chair every day. I folded my trash in the same fashion every day. I do not have OCD, as I do not do this for every thing. I just love order and standardization. And I may have obsessive tendencies.

 

EDIT: Added humidity.

 

EDIT2: Ok, it seems I may have misstated things, or at least said them in a way that led to misunderstanding. My system would not be so that someone could say "model X is wet". My system would be able to say that "This specimen of model X has a wetness of N". Thus, different factors that were brought up as changing wetness, i.e. nib material, feed design, and feed material, do not need to be looked at. They will all be taken as given when I refer to a pen. Same with flow adjustments. My end goal is to be able to have this conversation:

 

Me:""Hello. My Pelikan is currently a B on he wetness scale, but I find that too dry. Could you make it a C?

Nibmeister: "Yes, I could. Let me find my standard pen of wetness C an compare, and then I can alter your pen"

 

The point would come where the nibmeister would not need a standard, as they would have a feel for what each wetness was. Mr. Binder, for example, probably knows his scale by heart. And he has gotten good enough at it that if I order 10 Pelikan M200 nibs in M with a flow of 6, they will all be very similar, because he inherently knows what to do from practice and repetition. The same goes for nibs. It can be hand polished, whatever. No matter what it is, you can say that the nib you are holding has a wetness of N.

 

Also, please lay into me and point out errors in logic, or an overlooked variable, or something. That is what makes me reevaluate my design and make it better. Or feel free to evaluate it yourself and gives some thoughts.

 

On the issue of different papers, this scale should be durable among all of them given that they do not bleed. I chose to standardize it for now, but that can always change.

 

For inks, I know about surface tension and whatnot. For Heaven's sake, I am in a fluid mechanics class now. I sort of just wrote one and not the other, because viscosity will change things, too. So thanks for pointing that out. I also know about the wetness of the inks being different. That is why I want to standardize the ink I use. When this is done, maybe I will move on and add an ink wetness term to it, and I will find the equation governing that term based on various variables. But that is for another day.

 

Pen pressure and angle points have been noted, and are being thought about. Thanks for pointing those out.

 

Gravity changes are not only negligible, but can be accounted for. The acceleration due to gravity is known to extreme accuracy for very many places on Earth. Additionally, if the feed and capillary action can fight gravity and write on a ceiling, they should in the same way stop it (they do) when writing the correct way, on a table. Thus, I am thinking the gravity term is actually going to just not be included. Again, please argue, as I may be wrong.

Edited February 7, 2010 by nkk

[Mr Ink]

Thus, it has always annoyed me that people will state that pen X is wet, whereas someone else will say it is just right.

 

Me too.

 

It seems like a tall order though, because of the many, different variables that you mentioned. If you manage to pull this one off, I think you'd have set yourself up for a Penobel Prize. Wish you all the best of luck and looking forward to hearing about your results.

[ruud2904]

Nice thought, but will it be practical ? I don't think so. I think you just found your own mission impossible.

 

What about taking flow adjustments of a particular pen into account. I think that two pens of the same brand, same model, same production batch, but with different flow adjustments, will differ in outcome. Or differ due to differences in atmospheric circumstances. I am pretty sure that any pen will write different on high altitude, in the tropics. etc. And if you succeed in defining your standard, will someone else be able to use it without having to fly across the ocean to buy some cranes paper, build yourself a full scale labatory, sit down for 12 weeks to maesure the amount of ink per surface...BTW what unit will that be? Liters ink per square mile ??

 

Sorry for the sceptic above. Nice thought, but....

[nkk]

Nice thought, but will it be practical ? I don't think so. I think you just found your own mission impossible.

 

What about taking flow adjustments of a particular pen into account. I think that two pens of the same brand, same model, same production batch, but with different flow adjustments, will differ in outcome. Or differ due to differences in atmospheric circumstances. I am pretty sure that any pen will write different on high altitude, in the tropics. etc. And if you succeed in defining your standard, will someone else be able to use it without having to fly across the ocean to buy some cranes paper, build yourself a full scale labatory, sit down for 12 weeks to maesure the amount of ink per surface...BTW what unit will that be? Liters ink per square mile ??

 

Sorry for the sceptic above. Nice thought, but....

 

Trust me, I am skeptical that it will be done, but I want to try. As for everyone using it, they do not have to (as I said in the OP). I just want to have some standard. It will NOT be practical for everyone to use it, and I know that. However, for those that can use it, it will be extremely useful (or so I hope) As for flow adjustments across a model, this is not a generalization thing. Each pen will have its own rating. And yes, it may have some odd standards, but those need to be made. If I get this thing close to done, I will send Crane's paper (maybe 5 or so sheets) to anyone (within reason--I will not supply all of FPN) so that they can measure their nibs. The only requirement would be to post the results here, with whatever flow adjustments were made, and the nib size. I have already accounted for atmospheric pressure, and I did not remember humidity. Thanks for that.

 

I do not mean to sound defensive, but a lot of what you said I said in my OP. I admitted with would be a not widely used standard, and that it will not be practical for all. But on the same note, standardizing things is almost always done with some arm waving and saying "To make things easy, we will do this for no other reason than ease of use".

 

And what on Earth do you mean by Liters/Mile^2? It does not matter what I measure it in, the final result will just go through some dimensional correction to get a number with coherent and consistent units. I can measure the speed of your vehicle in furlongs per fortnight, or light years per millennium. Not practical, but the beauty of units is that there is trivial conversion between them within a given dimension,

 

Anyway, the point is I agree with you on most points, but think you missed the three or so times I said things like it is not doable for everyone, or that I wanted to do it, disregarding practicality.

 

-Nkk

[kernando]

For amount of ink, I'd think you'd have to get a very good scale or balance and take the before and after weight or mass. If you take evaporation as negligible, to leave it out, I'd say weigh or mass the pens capped. But then a drop can go a long line, so you have to go around making lines long enough for a measurable change in weight or mass.

 

Or, weigh the paper? It just has to be consistent.

 

I'd be happy if the people at the extremes stopped describing wetness, or at least admitted they're off, but I also can't remember having a problem with anybody being way off. Oh wait, there was one time a seller said something was dry, and it turned out the nib was slid onto the underside of the feed. That wasn't a failure of degree and opinion though.

[Yuki Onitsura]

I kind of like how different people have different opinions on things. Makes for some lively discussion and makes this lovely forum go round. That said, I would be quite curious as to the standardisation process.

 

Yuki

[ruud2904]

Anyway, the point is I agree with you on most points, but think you missed the three or so times I said things like it is not doable for everyone, or that I wanted to do it, disregarding practicality.

 

-Nkk

 

I didn't miss any of your points. I have read them carefully. I have been in the artillery branch and believe me, firing over long distances AND achieving the desired accuray is something mankind has been trying to do over centuries. It takes many trials and many tables of results for some reliability. This wetness quest is more or less the same problem. Small difference in one parameter, large difference in outcome. It fear your standard test for determining wetness of a pen with some accuracy will have to be some kind of duration test. But, be my guest, interesting enough to see what you come up with....

 

Edit : Oh, one more thing, there is a difference in wetness of a pen and wetness of the ink. They get mixed up easily, even on this forum and it took me some time to understand it a little and I am by no means an expert.

 

Ruud

Edited February 7, 2010 by ruud2904

[pay]

This sounds like a fun project, and you outlined it in a nice, thorough and intelligent way. I have three comments, however, which are a bit related.

 

1. You should also fix the angle at which pen meets paper, or even better (*see #3 below*) choose the angle to match the tip geometry of the nib, since that is probably how the nib was designed to be written with. You wouldn't compare the handling of two cars if one had extremely over/under-inflated or the wrong size tires, right? The contact of the nib tip to the paper is somewhat analogous to the tire contact patch.

 

2. A minor point, but the expression "area of the nib" is vague. Do you mean the entire area of the nib if you removed it and measured it alone? Or did you mean the area of the tip in contact with the paper? Most nibs have a long tail that extends into the section and has no impact on the flow of ink or wetness, in the sense that you could double the tail area and not affect ink flow.

 

3. Finally, and most importantly, it seems to me that while "fixing variables" is a good practical approach, it is probably not the best approach to this problem. FP writing (and therefore flow wetness) is really an optimization problem. As humans, we have lots of feedback (tactile, visual, even sound) by which we adjust the pressure, angle, speed of our writing to get a particular combination of ink and pen geometry to perform as we want it to. The wetness standard that you seek would be more useful if it compared the optimal wetness of each pen. To do this you would need to choose the combination of variables, from within a reasonable restricted range, which maximize the writing ink flow. To over-extend the car analogy, it is a bit like how a human shifting a manual transmission, incorporating the benefit of many feedbacks, can outperform an automatic transmission in a 0-60mph time test (I know, there are very good automatic transmissions now, but it took decades of engineering).

 

Sorry to sound like a referee, I am just trying to offer what I feel are some possible improvements on a topic near and dear to my heart. Good luck to you and press on with your project!

[pen2paper]

I like the intent of this project!

Have heard of wetness scales before.. you will consider these, and include them in your comparisons?

 

Also, I would suggest that you use a variety of commonly available papers.. those that are most globally standard.. so that your results will not become limited-after a period of time.

 

 

[WendyNC]

Regardless of the practicality, I can certainly see the appeal of the project. Doing it is completely outside of my skillset, but I can follow well enough to be thoroughly intrigued with the process.

[eric47]

The only requirement would be to post the results here, with whatever flow adjustments were made, and the nib size.

 

First interesting project.

 

Assuming that as much standardization that can be done is done, e.g. same paper, same ink, same angles, pressure, etc. I'm still worried about the part of the pen that can have a major affect the results, i.e. the nib. I can't speak about all nibs, but many are not 100% machine made with strict repeatable tolerances. Often they are still hand polished, with final hand assembly (in screw in units) or hand mounting. Anyone who's ever mounted a friction fit nib knows, placement of the nib on the feed is critical -- too far out, too far in, rotated off the feed have a major impact on performance. In the worse case, flow = 0.

 

So whenever I see remarks about x is dry, x is wet (where x is the same pen *model*), assuming that all else is equal (which often the case it is not), some of the difference might be sample variation. At best with your methodology, and assuming all things can be kept as equal as possible, you might get an interesting db of wetness variation for that particular model (and/or nib) as they come "out-of-the-box" from the manufacturer.** Letting in "flow adjustments" would undercut even that; just about any nib can tuned wetter or drier by the specialists and even the amateurs.

 

**That by the way on it's own would be pretty darn interesting.

Edited February 7, 2010 by eric47

[jar]

You are trying to standardize the wrong thing. It is not the pen that needs standardization but people.

[jmkeuning]

What about the thing that holds the ink? The cart or the converter? And the nipple that connects the feed and collector to the cart? Then, all of the foreign matter that gets stuck in there.

[Eldan]

I think you need a motorized apparatus that can grip a pen and draw circles on paper while while exerting a constant, measurable downward force on the nib. You have to slide the paper slightly after each revolution so the nib sees new surface. Pen manufacturers already have machines like this. Instead of trying to weigh the paper I would weigh the pen, once after filling and again after drawing a fixed number of circles. Knowing the density of the ink, you can measure pen wetness. My suggested units would be ml / m (milliliters of ink per meter of writing) at your standardized downward force and angular velocity.

 

I expect most of the variables you mentioned such as barometric pressure and humidity will have a miniscule effect on the outcome, except maybe high altitude.

 

EDIT: This link might point you in the right direction.

Edited February 7, 2010 by Eldan

[OldGriz]

Thus, it has always annoyed me that people will state that pen X is wet, whereas someone else will say it is just right.

 

This is just human nature.... it is the same as someone stating that this chili is too hot and the other person stating it is not hot enough....

Wetness is an individual situation..... I recently handed someone one of my Parker 51 Vacs that is virtually perfect for me in regard to wetness and smoothness... they stated it was too wet and too smooth for them... they preferred more feedback from the nib and a drier writing experience.... So who was right.... I was, of course, the pen is mine and writes as I want it to write... if the pen was his he would be right.... because it did not fit his standard of writing quality.

Richard Binder has a wetness scale that he uses so people can tell him how wet they want the pen he is doing for them...

Was it produced using formula, scientific testing, etc. I doubt it very very much...

It was most likely created using experience he has had altering more nibs than I will most likely see in my lifetime and dealing with thousands of customers and seeing what they wanted in a nib.

[bgray]

Richard Binder wrote an article that will help.

 

http://www.richardspens.com/?refp=wysiwyg

[Richard]

It is not ink's viscosity that is at issue, burt rather its wetness.

 

Viscosity is defined as the internal friction of a liquid, which exhibits itself as "thicnkess." Water is a relatively "thin" liquid. Maple syrup, whose viscosity is higher, is a relatively "thick" liquid. All fountain pen inks, assuming that they have not been artificially altered, have essentially the same viscosity. What makes them perform differently is their wetness, which is inversely proportional to surface tension. Surfactants are used to affect the wetness, and no two surfactants will affect the wetness in exactly the same way or to the same degree.

 

You have overlooked a critical factor, the wettability of different metals. Platinum-group metals for example, are more wettable than gold. How do differences in wettability affect nib performance.

 

You've also overlooked another critical factor, the wettability of different feed materials, which affects flow. Hard rubber is hydrophilic, highly wettable, while plastics are hydrophobic, water repellent. To make plastic feeds more wettable, manufacturers coat them with wettability-enhancing materials. During assembly, some of this material may be abraded away by handling. How much? Where on the feed?

 

Feed design is a third critical factor; the same pen, with its feed changed, can perform vastly differently.

 

The shape of the tip has an effect; two otherwise identical nibs (if there actually were such a thing), one with a spherical tip and the other with a slab-sided tip, even if their writing pads are identical in size, will produce different results. A nib that has "baby bottom" will not perform the same as a nib that is properly shaped. And so on.

 

And, apropos of the previous point, there is no such thing as two identical nibs. Slit width, the taper of the slit (or lack thereof), the presence or absence of a "Grand Canyon" slit shape (narrower at the bottom surface of the nib than at the top) or a reversed "Grand Canyon" slit (wider at the bottom surface than at the top), the finishing of the slit walls, the thickness and quality of plating, if any, the choice of alloying metals so that even two 18K nibs will differ, all these and probably more that don't come to mind can affect the performance of a pen.

 

The adjustment of the nib relative to the feed affects flow, not only in terms of how tightly they are pressed together (or not) but also in terms of how they're adjusted longitudinally. Manufacturing variables here are manifold.

 

The weight of the pen must be factored out by testing under a standard writing pressure. A full pen is heavier than that same pen will be when it is emptied; similarly, the choice of cartridge or converter (for pens that offer it) has an effect on weight. The position of the piston in the bore of a piston-filling pen affects the pen's center of gravity and thereby changes the writing pressure that the pen will apply of its own weight. Two pens that weigh the same but are of different lengths will behave differently -- remember, you can't test with the pen vertical; you have to support it by its tail end while holding it at an angle above the paper (what angle? 45°? 50°? 65°?). For this reason, you must test using a fixture that applies a tightly controlled pressure.

 

You will also have to perform all of your testing in the same location; the measurement will not be repeatable anywhere and everywhere, because gravity, wile almost the same everywhere, is not exactly the same. It's inversely proportional to the distance from the center of the Earth, and this means that it's stronger in Bozeman, Montana than it is in Missoula, Montana (because Missoula is higher in the mountains), stronger at the poles than at the Equator (because the planet is an oblate spheroid due to its spin), and stronger in St Louis, Missouri, than it is in Adelaide, South Australia (because the planet is pear-shaped as a result of continental distribution).

 

You mention humidity and its effect on capillary action with water (i.e., ink), but you need also to consider its effect on papers and on the vapor pressure of ink relative to atmospheric pressure.

 

It may be necessary to consider also whether the pen will write on the ceiling. A fountain pen adjusted for normal flow (in the range from about 4 to 7, as I figure things) will write on the ceiling because capillary action can overcome the effect of gravity; but a pen that's adjusted too wet might not write on the ceiling because gravity can pull the meniscus far enough away from the writing pad that capillary action can't pull the ink onto the paper.

Edited February 7, 2010 by Richard

[jmkeuning]

1. Develop the testing scheme.

 

2. Order ten "identical" pens (I'm thinking safaris) from multiple dealers.

 

3. Apply the testing scheme.

 

4. Consistent results?

[Mr Ink]

.... it is the same as someone stating that this chili is too hot and the other person stating it is not hot enough....

Wetness is an individual situation.....

 

Funny that you should mention chilli hotness, OldGriz. There is an actual scale for measuring that - the Scoville scale (devised by William Scoville in 1912). The unit of measurement is the SHU (Scoville Heat Unit).

 

Different individuals can tolerate / like different levels of chilli hotness. Similarly, different pen-users can enjoy / dislike different degrees of nib wetness. However, the wetness of a pen should be measureable objectively. Just my 2 cents' worth.

[Mr Ink]

 

Richard Binder has a wetness scale that he uses so people can tell him how wet they want the pen he is doing for them...

 

 

This is interesting. Can someone please provide a link to Richard's wetness scale.