Inkwell Evaporation Rates

[D Armstrong]

There have been several thoughts expressed recently here, expressing concern about how useful old inkwells are due to evaporation rates. It occurred to us that it might be useful to have some empirical evidence either for or against (or, more likely still, both) this feeling. We have a number of inkwells in our stock, spanning a couple of centuries and any number of designs, so we are in a good position to try out a variety of types. It is our hope that this will provide everyone with a better idea of what to look for, or not, in an inkwell for regular use. (Conversely, we may even prove that inkwells are useless in modern life. Who knows?)

 

This is the proposal to date:

 

1) Six inkwells of different design will be filled and closed with nothing more than their original lids. Included will be:

• a glass well with a simple gravity-closing hinged lid;
• a glass well with a silver snap-close hinged lid;
• a metal well with glass insert and a hinged outer cover (thus with space between the insert and the cover);
• wooden well with glass insert and an unhinged cloth-lined wooden lid;
• a glass writing-box bottle, with threaded brass lid;
• a pottery ink bottle, with a cork.

 

2) Additionally, we will have two controls: a modern glass ink bottle, filled and screwed tight, and an open container. This will give us a good baseline of extremes with which to compare our results.

 

 

3) All containers will be kept in the same enclosed space (a section of our lawyer's bookcase.)

 

 

4) Each container will be monitored by weight daily, for two weeks. (Mass is more accurate than volume, as we won't lose any volume to the testing equipment. And it's cleaner and easier.) Data will be recorded and converted to 'per cent loss" and the final results graphed.

 

There are, however, some issues:

 

• We have no means of controlling relative humidity, although the weather is forecast to remain stable (dry) for the next few weeks, and the enclosure should minimize fluctuation.
• We also face the issue of what substance to use as our "ink." While our first inclination was "ink, of course!" it may not be that simple. Inks have different evaporation rates, and those used by the community are wildly varied. What struck us as an option in discussing this is water. Most inks use water as a base solvent, it is clean and cheap, it's qualities are universally known and recognized (thus, it is easier for someone to compare their favorite ink to water, than to another kind of ink they may never have used before.) And, we are testing the qualities of the containers, not the liquid.

 

We are interested in your thoughts on this. What issues have we missed? Does it make sense to use water rather than ink? Is two weeks long enough to gather data? Given that we know that the open container will evaporate far more quickly, should we make it big enough to hold liquid for the entire period? (This last is, obviously, only an option if we go ahead with the water plan, as I'm not going to sacrifice a bucket full of ink, even in the name of pen science!)

 

Thanks for your brain power, and we look forward to your thoughts.

[Pensfan]

As long as you use the same liquid in each bottle, whether it is ink, purified water, tap water, etc, you should be fine.

 

I am looking forward to this test!

 

[churl]

While the information you get regarding relative evaporative loss would be reasonable, not using ink or a solution of similar molarity would be a limitation (colligative properties). And even if you can't control humidity, measuring it would be useful as well, as well as temperature. Now, if you ask me what is the molarity of a standard ink solution, that is another bucket full of worms entirely. And that's not even getting into chemical additives that may affect surface tension...

 

And finally, make sure to use a scale accurate enough to gauge that small of a loss relative to that heavy of an object.

 

Those are the only things I can think of. Good luck!

[WOBentley]

I think that consistency is the key here. Water is likely fine (or all the same ink color/brand etc.) to minimize variation. Relative humidity will not matter if all are exposed to the same, if humidity is high you may need to extend test period to determine differences. My final suggestion, is to have an additional inkwell design for my curiousity (of course I have my personal interest )...I have often wondered if attaching some sort of thin rubber (silicone, or foam) sheeting cut to form a gasket on both sides of the typical hinge inkwell (thereby having rubber or silicone or perhaps high density foam, or even an automotive "O" ring that would likely have to be "carved" to allow complete sealing)form a seal would work to eliminate the problem. I have a Mountblanc inkwell that I don't use because evaporation was too high. Would love to find a solution as long as you are doing the experiment!

Edited January 30, 2011 by WOBentley

[D Armstrong]

And finally, make sure to use a scale accurate enough to gauge that small of a loss relative to that heavy of an object.

 

I'm eyeing a 0.01g "jeweller's scale."

 

'"Honest, officer, I'm just measuring ink evaporation. No, really..."

[D Armstrong]

My final suggestion, is to have an additional inkwell design for my curiousity (of course I have my personal interest )...I have often wondered if attaching some sort of thin rubber (silicone, or foam) sheeting cut to form a gasket on both sides of the typical hinge inkwell (thereby having rubber or silicone or perhaps high density foam, or even an automotive "O" ring that would likely have to be "carved" to allow complete sealing)form a seal would work to eliminate the problem. I have a Mountblanc inkwell that I don't use because evaporation was too high. Would love to find a solution as long as you are doing the experiment!

 

I've actually been playing with that thought for awhile, myself. Large diameter o-rings? Custom-turned cork inserts, with brass pull-ring? Not enough hours in the day, I'm afraid. One issue which may rear it's head is that the nature of a hinge is such that the opening is wedge-shaped. So, for a gasket to work, it would have to be either excruciatingly thin, or slightly wedge-shaped, which would be difficult. Or, of course, you could re-shape the hinge to raise the whole cap up the same amount as the thickness of the gasket. And, of course, for some folks authenticity is paramount (which is what made me think of the cork insert.)

 

Mind you, I think I still have some rubberized cloth around here somewhere...

[opitzs]

Interesting, especially as I am putting out feelers to buy one myself. I agree with churl, measuring temperature and humidity could provide very interesting data.

 

Bye

Sven

[Paddler]

Use distilled water for the liquid. If you use ink, the evaporation will slow as the dyes become more concentrated. Your data will get lost in the noise as the rate slows. You might think that this is what you are trying to measure, but it is not. You are trying to measure a characteristic of many different inkwells - not many different inks.

 

Perform the experiment long enough that you get a good spread of data. Check everything when the open container is nearly dry.

 

Paddler

[whichwatch]

Sounds fascinating - I look forward to seeing the results.

 

I find myself wondering if the surface area of the container opening will have an effect. If the surface area (theoretically) exposed to air in a bottle is larger than that of an inkwell, wouldn't that cause evaporation to occur at a faster rate?

 

I understand the theory and desirability of testing using water. But isn't it possible that if a container doesn't seal as tightly, leading to greater loss through evaporation, it might also have a greater detrimental impact on the ink within?

[pelman]

As long as all the samples are subjected to the same test conditions this should be a valid study.

 

Can't wait for study results. I just bought a couple of ceramic pieces with cork top which I will use as inkwells. Let the evaporation begin.

[D Armstrong]

I find myself wondering if the surface area of the container opening will have an effect. If the surface area (theoretically) exposed to air in a bottle is larger than that of an inkwell, wouldn't that cause evaporation to occur at a faster rate?

 

 

Yes! The open control container would have to be of a similar diameter.

 

 

I understand the theory and desirability of testing using water. But isn't it possible that if a container doesn't seal as tightly, leading to greater loss through evaporation, it might also have a greater detrimental impact on the ink within?

 

 

Heh heh. That is exactly the point of the test. If we can establish what factors affect evaporation, independent of the nature of the liquid, then we will know what to avoid in an ink storage container. If it doesn't hold water well over an extended period of time, then it definitely won't do for ink (in the context of fountain pen use.)

[rockspyder]

Great idea! I agree with previous posters, that relative evaporation rates are probably what we're after, rather than absolute ones with ink, etc. Two weeks may be a bit short - I have a spherical bottle with a cork, filled with methylated spirits, on my desk (don't ask why. Also someting to do with evaporation rate. It's another story!) It has been in my office, unopened, for the past 8 years, and the level of spirits (which evaporates a lot faster than water) has dropped by about 10%. Perhaps, for a short-term study on relative rates among different containers, a more volatile substance would be better.

[D Armstrong]

Great idea! I agree with previous posters, that relative evaporation rates are probably what we're after, rather than absolute ones with ink, etc. Two weeks may be a bit short - I have a spherical bottle with a cork, filled with methylated spirits, on my desk (don't ask why. Also someting to do with evaporation rate. It's another story!) It has been in my office, unopened, for the past 8 years, and the level of spirits (which evaporates a lot faster than water) has dropped by about 10%. Perhaps, for a short-term study on relative rates among different containers, a more volatile substance would be better.

 

An interesting point. I had actually been thinking about running it for a month, rather than two weeks. It might be worth considering two months, even. I suspect, though, that any longer than that might belabor the point: if there is little evaporation after a month (or two), then we have effectively proved that inkwells are still a viable option for longer-term storage, despite popular misconception. And, obviously, if it all evaporates quickly, the converse is true.

 

I must admit to being enthusiastically partisan: there are some really nifty inkwells that are just crying out for ink. Fortunately, I can quell my personal opinions for the sake of science ; )

[opitzs]

So no 8 years masterplan?

[tmenyc]

This is very interesting. I brought my Esterbrook double 444 set to work when I started this job in October, filled one side with BSB and the other with Noodlers Black. I think I filled them both to the same level, more than half, certainly not full. I use the black more often than the blue, the former for writing, the latter for signing. Same 2668 nibs in both. Yet, last weekend, the BSB had run dry to the point that it wasn't picking up anymore, so I checked both sides (not a risk-free venture with BSB, I gotta say....) The black was maybe 7/8 dry. The only explanation I can think of is their different chemistries....any thoughts?

 

Tim

[D Armstrong]

filled one side with BSB and the other with Noodlers Black.

 

Sorry, but I have to ask: what's "BSB"?

 

As a vintage pens guy, I tend to steer clear of Noodlers.

[texaspenman]

Looks like a well thought out experiment. Keep us posted!

[Randal6393]

Great experiment but penmen for centuries simply added a bit of distilled (or rain) water every so often to the batch of ink they were using. A quick letter or two would tell them whether they needed to add a few drops of ink or more water to make the consistency correct.

 

I am currently doing a set of wedding invitations with Old World Iron Gall Ink and a Brause Rose nib. Every few days, I bring the level back up to the fill line with water. Don't see any lightening or dilution in my finished invitations. So far, I have written out fifty invitations and have another thirty to go. Still have an almost full bottle of ink.

 

Enjoy,

[pelman]

filled one side with BSB and the other with Noodlers Black.

 

Sorry, but I have to ask: what's "BSB"?

 

As a vintage pens guy, I tend to steer clear of Noodlers.

 

 

BSB - Noodlers Bay State Blue

[txinsk]

This is very interesting. I brought my Esterbrook double 444 set to work when I started this job in October, filled one side with BSB and the other with Noodlers Black. I think I filled them both to the same level, more than half, certainly not full. I use the black more often than the blue, the former for writing, the latter for signing. Same 2668 nibs in both. Yet, last weekend, the BSB had run dry to the point that it wasn't picking up anymore, so I checked both sides (not a risk-free venture with BSB, I gotta say....) The black was maybe 7/8 dry. The only explanation I can think of is their different chemistries....any thoughts?

 

Tim

 

Two comments here. First I would not be surprised if BSB evaporated faster, however, that is a characteristic of an ink. The second point is that maybe all the two different inks do not flow at the same rate. Comparing BSB & highland heather in otherwise identical preppies I found the following. BSB flows faster and dries faster. If the same is true for BSB and black (whichever one you use) then the ink would run out faster due to both evaporation and more ink used per inch. If the pen is inked, write with both sides and look at the results carefully. I bet they are similar but not the same. I will also add that it is possible that the two different esterbrook nib/feed units behave differently, albeit slightly, this can make a difference too, but I think the ink differences are the real reason.

 

Rick