Suggestions For An Approach Or Methodology To Chromatography?

[A Smug Dill]

With too much "spare" time on my hands, I'm gearing up to catalogue (at least, say, two-thirds of) the 300 commercial inks I have. The format on which I've more or less decided is to use pages of polypropylene pockets for 2ʺ×2ʺ slides, with 20 pockets in five rows on a page, using a row of four pockets for each ink. That will allow me to store up to eight 'slides' per ink, and I'll probably keep a small writing sample on the five most common or numerous types of journal paper we have, perhaps a sixth 'slide' on my personal idea of an international standard of fountain pen friendly paper — Rhodia Dotpad 80gsm bright white paper — to capture summary information, leaving the two sides of the remaining pocket for 'swatch cards'.
 
Taking my inspiration from Mountain of Ink, I ordered a rubber stamp and a stamping pad for waterproof pigment ink, to print ink bottles on 210–220gsm mixed media paper cut to the right size, and make it easier to (develop and) adhere to a format for information-dense swatch cards. The tentative format is shown in the image below. The swab will tell me about the ink's potential for shading, the saturated splat will tell me about its potential for sheen, the part of the image representing the ink will be close to the ink's colour as it is in the bottle, and the sections of the vane on the feather quill to show cross-hatching before and after washing with a water brush pen, in part to tell me about water resistance.
 
That leaves one side of the last pocket available for displaying the chromatography of the ink. But what is the 'right' or best approach to putting down just the right amount of ink on the piece of lab filter paper? I want that 'slide' to aid in identification of inks, comparing inks for similarity in constituent colours, as well as tell me about water resistance; all that in a squarish area instead of a long rectangular strip that is traditionally used for chromatography.
 
As shown below, I've tried writing on the paper with a pen (fitted with an EF nib, in this case), using an O-ring to pick up and dump ink onto the paper (which produces quite inconsistent results), and placing a tiny droplet of ink on the paper using a blunt tip syringe needle of very fine gauge. Chromatography of the drawn lines seem to show the most consistent results, but can look anaemic, and when compared to the chromatography of the droplets it seems there is something not achieved simply because there was insufficient ink to spread fully. The chromatography of the droplets come out richest in colour, but due to the small area, I'm unsure whether if given sufficient area to run the larger volume of ink in a droplet will eventually give similar colour breakdowns to the drawn lines. The chromatography of the thick rings seem to be a good middle ground between the two, but I find it difficult to get a relatively even line width around the circle.
 

 
What would you do?

[Tas]

Middle top row 🥰

 

Youre going to have so much fun!

Edited August 23, 2020 by Tas

[A Smug Dill]

Thanks Tas.

 

I should also acknowledge your influence on my swatch card format. I'm sure the washing with a water brush pen idea came at least partly from your 'vase' cards; I believe Kelli does hers in the 'ink' part inside each printed bottle, whereas I'm trying to use the technique I picked up from Nick Stewart's artwork to make the 'ink' on the swatch card look more like the colour of the liquid ink in the bottle.

[Tas]

Awww. Honoured.

Can't wait to start seeing you roll this lot out . . .

(Coincidentally used Kiowa Pecan for the first time last weekend on a commission for a french hen - loved it)

[LizEF]

... commission for a french hen ...

Wow! She commissioned a self-portrait? Amazing. Never imagined you could communicate with chickens....

[LizEF]

Dill, the only thing I can think to contribute to your discussion is this question: Is it useful to know relative travel of the different dyes, or only to know which dyes are present? If the former, then you may need a longer strip despite your size limit. If the latter, then I find myself drawn to the same square as Tas. I suspect only someone who's done a lot of these, and used the inks long enough to give careful consideration, could tell you whether the distance traveled by the different dyes tells you something useful. I know from brief mixing experience that knowing the different dyes is useful for that purpose.

 

Looking forward to your catalog (should you choose to share images of it).

[A Smug Dill]

Never imagined you could communicate with chickens....

 

"Nobody... calls me... chicken!"

 

Is it useful to know relative travel of the different dyes, or only to know which dyes are present?

A bit of both, but primarily because I can't really tell one blue dye from another (in terms of name, chemical composition or properties, etc.) if they look similar on something like coarse filter paper.

 

Here are the artefacts from some earlier experimentation:

 

How far the yellow and turquoise dyes travelled up the long strips apparently depended on the amount of solvent — in this case, water — available to facilitate transport; if allowed by circumstances, those dyes will travel right up to the edge of the piece of filter paper and collect there. (I'd thrown out a long strip on which the bottom end has been allowed to stay steeped for too long; but you can still see this in the rectangular piece in the top right corner.)

 

I'm no physicist or chemist, but given the use of the same medium-speed filter paper, I'd reason that the amount of time and the surface area that is submerged would be the primary factors to affect how much water is soaked up; I don't know if temperature plays a part. However, these 'experiments' I'm doing are all very amateur and casual, and I'm neither going to try to keep everything under controlled lab conditions from strip to strip and ink to ink, nor willing to stand there and watch the water level rising waiting to pounce and pull the filter paper out once the water level has risen 75%–80% up its height. So, an approach that 'always' takes three large drops of water from the same eyedropper, as the primary means of controlling how much solvent is available, is probably easier; and that means chromatography artefacts that are circular or radial visually.

 

If the former, then you may need a longer strip despite your size limit. If the latter, then I find myself drawn to the same square as Tas.

I'm more drawn to the slide on the right here:

 

 

I call it Koala is mad that its head got transplanted onto a penguin.

 

I suspect only someone who's done a lot of these, and used the inks long enough to give careful consideration, could tell you whether the distance traveled by the different dyes tells you something useful. I know from brief mixing experience that knowing the different dyes is useful for that purpose.

If I encountered an ink that seemingly have the same constituent colours, but the turquoise dye travels not nearly as far as the yellow, then I must conclude it's a different ink from Standard Bindery Stargaze, with or without the ink appearing similar when writing with it with a pen. So, the relative travel of the different dyes indeed matter, more so than the absolute distance of travel (which would be limited by the physical dimensions of the strip and the amount of solvent available).

 

Thinking about my use cases some more, where the effort and material expense of doing chromatography and keeping the artefacts on file might be worthwhile — as opposed to just fun or 'artistic' — is the identification of an ink, either in a pen because I'd neglected to put in an entry in the log book on the day of filling it, or in a sample vial on which the label has fallen off. (I've come across both of those issues in the past couple of months.) If I'm really burning to know what ink that is, how will I be able to find out at the minimum cost? Proper filter paper is relatively expensive compared to, say, mixed media art paper on a per unit area basis; but, last time I tried to find out what was in a vial, before my order of filter paper arrived, it took me ten strips of paper towels (and grabbing eight different bottles of candidate inks) and half an hour to find out.

 

So, something like the squarish slide here might look boring yet fulfil its purpose adequately:

 

 

(OK, who am I kidding? The effort to do chromatography slides for 200–300 different inks and build a 'reference' library, when the need to do a look-up only happens once in a blue moon, is neither the most time-effective nor the most cost-effective approach per occasion when the upfront investment is apportioned.)

 

Looking forward to your catalog (should you choose to share images of it).

Can't wait to start seeing you roll this lot out . . .

I'll think about that. My primary motivation is actually because I did something like this:

 

 

last month trying to decide on which similar inks would make good sets of nine for this type of comparison:

https://www.fountainpennetwork.com/forum/topic/279274-inky-t-o-d-color-swatches-brown-please-post-your-pictures-and-tell-us-your-thoughts/?p=4340448

 

but I was quickly overwhelmed, so I thought a personal ink catalogue would be useful, but the common swatch card formats I've seen so many of you do (so wonderfully) wouldn't really capture what I want to know when I go to select inks from my collection. So I've spent the past month thinking about how to go about creating such a catalogue — a mini ink review in N (Powerpoint?) slides format for my and my wife's own reference, I suppose — and ordering the required tools and materials piecemeal.

 

But I suppose just showing selected swatch cards from time to time would save me from 'having to' prepare one-sheet ink comparisons afresh, if the goal is to showcase the inks without necessarily showing how they would appear coming out of a EF nib or a broad-edged nib.

[Eclipse157]

If you like the strip (I do) done with the EF fountain pen, then draw multiple lines over the same spot (I should say line but you get the meaning), just make sure you let the ink dry between redraws. This way you'll have much more dye on the strip, possibly enough to fix the anaemic look of it. As an added bonus (but I can understand if someone says it's a drawback) your chromatographies will also display information about the ink's water resistance.

 

Edit: typos.

Edited August 24, 2020 by Eclipse157

[A Smug Dill]

If you like the strip (I do) done with the EF fountain pen, then draw multiple lines over the same spot (I should say line but you get the meaning), just make sure you let the ink dry between redraws. This way you'll have much more dye on the strip, possibly enough to fix the anaemic look of it. As an added bonus (but I can understand if someone says it's a drawback) your chromatographies will also display information about the ink's water resistance.

 

Thank you for your input. I agree, getting visibility into the ink's water resistance is a bonus, although filter paper isn't exactly representative of 'fountain pen friendly' paper, or even absorbent paper. There is also the question of whether water resistance increases with time the ink has had to 'cure' on paper; in particular, I was considering the implications when testing iron-gall inks, and one of my candidate formats was to write the clock time with the ink, at four intervals one minute (or several minutes) and 1cm apart from each other along one edge of a rectangle, then do the chromatography. That's probably a better idea for more in-depth ink review exercise than cataloguing inks using two-inch 'slides', though.

 

I've taken to drawing two parallel lines on some of the candidate formats, both to deposit more ink for spreading as well as seeing whether distinctly visible marks will remain. I was tempted to write some Chinese hanzi instead, as the ink 'glob', but intersections of horizontal and vertical pen strokes can be messy on filter paper even before wetting.

 

Edit:

 

Actually, now I wonder if chromatography on proper filter paper will tell me anything meaningful about an ink's water resistance on other types of paper:

 

Edited August 24, 2020 by A Smug Dill

[LizEF]

I call it Koala is mad that its head got transplanted onto a penguin.

 

 

 

So, the relative travel of the different dyes indeed matter, more so than the absolute distance of travel...

 

Yes, that does seem useful. It would also be interesting to know if certain colors always travel farther than other colors. (And it would be extremely amusing if their relative travel were opposite depending on whether one were in the northern or southern hemisphere. I sense amusing story ideas forming in some strange part of my brain.)

 

I've found it helpful to think of my long-term goals more as "spend time working on" than "accomplish X" - helps keep me from feeling overwhelmed by the volume of work to be done - but that's me. Some people are highly motivated by the "accomplish X" mindset (and probably more productive than I). Anywho, I wish you well in your catalog building, regardless of what and whether you share anything - and certainly don't want to add anything to the load! If you occasionally share an ink swatch of koala-penguin, I'll just enjoy it as-is.

[Eclipse157]

Hmmm why do I see your chroma strip completely submerged by water?

 

It's not for chromatography right?

Edited August 24, 2020 by Eclipse157

[A Smug Dill]

Hmmm why do I see your chroma strip completely submerged by water?

 

It's not for chromatography right?

 

No, that's just testing the inks' water resistance on Arttec Como paper by soaking, not chromatography. I have some strips of that paper on my cutting mat (waiting to be thrown into the bin) when I was looking for something to write on, in order to test whether Standard Bindery Stargaze was water resistant given the apparent staying power of the grey dye in it from the chromatography; my recollection is that Stargaze is not water resistant at all.

 

The "this side up" was to remind myself which surface should face upwards when the strip was standing at a slant in the beaker, in case there is some staining from dyes running into the water but getting reabsorbed by other parts of the paper surface. There is (or was) some writing on the other side as well to avoid that from happening.

Edited August 24, 2020 by A Smug Dill

[A Smug Dill]

Anywho, I wish you well in your catalog building, regardless of what and whether you share anything - and certainly don't want to add anything to the load!

 

 

What I meant, when I said I was overwhelmed, was that in order to group the brown inks I have into sets of nine — with the real 'work' intended actually being the one-sheet comparisons of each set — by similarity in hue, I had to first create thirty-odd 'swatches' that can be physically arranged (and rearranged), but the quick-and-dirty writing samples and swabs done with a dip pen and q-tips respectively are not the easiest to work with; and, once I've done the first set of nine, I started to doubt myself and wonder if I should also (create and) include swatches of yellow and orange inks in the next selection process. Having an already completed catalogue on hand would have made it easier for me to actually get to and get on with producing the one-sheet comparison I had in mind; I couldn't get started without making a selection of inks, although it was possible to just grab nine inks haphazardly and compare them, never mind the differences in hue.

 

Sharing images of what I've already physically produced wouldn't add much to the workload, but I simply have to consider what I hope to gain or accomplish by doing so. What would be the information I want to release in a deliberate and controlled manner, and why? It may also mean I have to change the format of my catalogue, to make it better match the information release model. That's the reason why I said I'll think about it.

[amberleadavis]

I like seeing the different types and I've enjoyed the discussion.

[LizEF]

What I meant, when I said I was overwhelmed, was that in order to group the brown inks I have into sets of nine — with the real 'work' intended actually being the one-sheet comparisons of each set — by similarity in hue, I had to first create thirty-odd 'swatches' that can be physically arranged (and rearranged), but the quick-and-dirty writing samples and swabs done with a dip pen and q-tips respectively are not the easiest to work with; and, once I've done the first set of nine, I started to doubt myself and wonder if I should also (create and) include swatches of yellow and orange inks in the next selection process. Having an already completed catalogue on hand would have made it easier for me to actually get to and get on with producing the one-sheet comparison I had in mind; I couldn't get started without making a selection of inks, although it was possible to just grab nine inks haphazardly and compare them, never mind the differences in hue.

 

Sharing images of what I've already physically produced wouldn't add much to the workload, but I simply have to consider what I hope to gain or accomplish by doing so. What would be the information I want to release in a deliberate and controlled manner, and why? It may also mean I have to change the format of my catalogue, to make it better match the information release model. That's the reason why I said I'll think about it.

Ah, got it! Makes perfect sense.

[bunnspecial]

So, just as a couple of thoughts as an analytical chemist with a lot of interest and practical experience in chromatography(albeit primarily instrumental techniques-gas and liquid chromatography)-here are my thoughts.

 

Paper is a perfectly fine medium for separating pigments. Often, in the lab, we will instead do "thin layer" chromatography, where we use a plate of glass, aluminum or plastic(doesn't matter-mostly a preference on handling and cost) coated usually in silica gel. The way we do usually is to draw a line(in pencil, always) part of the way up the plate, then "spot"(deposit what we're interested in) along the line. It is "developed" by standing up in a solvent chamber with only the bottom end(below the spot) submerged in the solvent, and the solvent travels up by capillary action. Once the solvent is near the top, you pull it out and draw a line at the solvent front, or the highest point it traveled. You can then, if you desire, calculate a value called the Rf based on the total distance traveled(spotting line to solvent front) and the distance each spot traveled. For a given substate and solvent system, the Rf should remain constant for a given compound(pigment in this case).

 

As in all types of chromatography, the amount any one particular compound(or the speed it travels along the chromatography column) is entirely dependent on two interactions-the interaction between the compound and substrate(paper in this case) and the interaction between the compound and the solvent. Something that is completely soluble in the solvent at not at all attracted to the substrate will travel with the solvent front, while something that is not at all soluble in the solvent and strongly attracted to the substrate will not move off the starting point. It's desirable to find a solvent where all the compounds fall somewhere in between these two extremes, but will still separate out. Usually that is done by changing the polarity of the solvent. Often times in the lab, we will use mixed solvent to tune just the right polarity, but that may not be something you want to get into.

[LizEF]

So, just as a couple of thoughts as an analytical chemist with a lot of interest and practical experience in chromatography(albeit primarily instrumental techniques-gas and liquid chromatography)-here are my thoughts.

 

Paper is a perfectly fine medium for separating pigments. Often, in the lab, we will instead do "thin layer" chromatography, where we use a plate of glass, aluminum or plastic(doesn't matter-mostly a preference on handling and cost) coated usually in silica gel. The way we do usually is to draw a line(in pencil, always) part of the way up the plate, then "spot"(deposit what we're interested in) along the line. It is "developed" by standing up in a solvent chamber with only the bottom end(below the spot) submerged in the solvent, and the solvent travels up by capillary action. Once the solvent is near the top, you pull it out and draw a line at the solvent front, or the highest point it traveled. You can then, if you desire, calculate a value called the Rf based on the total distance traveled(spotting line to solvent front) and the distance each spot traveled. For a given substate and solvent system, the Rf should remain constant for a given compound(pigment in this case).

 

As in all types of chromatography, the amount any one particular compound(or the speed it travels along the chromatography column) is entirely dependent on two interactions-the interaction between the compound and substrate(paper in this case) and the interaction between the compound and the solvent. Something that is completely soluble in the solvent at not at all attracted to the substrate will travel with the solvent front, while something that is not at all soluble in the solvent and strongly attracted to the substrate will not move off the starting point. It's desirable to find a solvent where all the compounds fall somewhere in between these two extremes, but will still separate out. Usually that is done by changing the polarity of the solvent. Often times in the lab, we will use mixed solvent to tune just the right polarity, but that may not be something you want to get into.

Thank you! This makes me wonder strange things, like what would happen if I used ammonia (bleach, etc.) instead of water. I doubt I'll experiment any time soon, but I'm bookmarking anyway.

[A Smug Dill]

So, just as a couple of thoughts as an analytical chemist with a lot of interest and practical experience in chromatography(albeit primarily instrumental techniques-gas and liquid chromatography)-here are my thoughts.

Thank you! Your input is much appreciated.

 

As in all types of chromatography, the amount any one particular compound(or the speed it travels along the chromatography column) is entirely dependent on two interactions-the interaction between the compound and substrate(paper in this case) and the interaction between the compound and the solvent.

So, would I be better off refining the method and/or technique for placing a suitable amount of ink on a piece of filter paper that measures ~50mm in the dimension along which the constituent compounds will spread (and just scale any observations and/or Rf calculations), instead of using longer strips, if granularity or resolution is not the primary concern? In the same vein, I would write with a lower x-height using an Extra Fine nib, to convey the same amount of information (and meta-information, such as shading and sheen exhibited) pertaining to an ink, in a smaller area than someone who writes (and prefer to write) with a Broad nib.

 

Usually that is done by changing the polarity of the solvent. Often times in the lab, we will use mixed solvent to tune just the right polarity, but that may not be something you want to get into.

Yeah, I think I'll stick with water that has passed through the filter in my jug. Strange as it may seem to me after moving to Australia all these decades, distilled water (and clear ammonia solution, grrr) isn't something readily available from supermarkets here, even though it's readily recognised that such would be better for use in irons and such. Or use koala juice.

 

I just found a Chinese seller on eBay that sells 15cm round filter paper (Why don't they sell that stuff in rectangular sheets, dammit?) for just over half the price I paid for the last lot, so I've ordered 200 sheets of those to see how they fare. A 15cm circle will yield four "two-inch" slides, or five 2cm-wide strips ≥10cm in length (or six 2cm-wide strips 9cm in length, with two 2cm-wide strips of ~7.5cm for scrap and throwaway experimentation, if I'm feeling stingy), so what I've got left from the first pack will just make it for 300 inks if I don't have to do more proof-of-concept testing (and don't screw things up at all in actual execution of the cataloguing project), but if this other paper works I'll just use that from the very start, and not feel so constrained or pushed (for the sake of consistency) into ordering another pack of the same paper while it's still available.

[bunnspecial]

Thank you! Your input is much appreciated.

 

 

So, would I be better off refining the method and/or technique for placing a suitable amount of ink on a piece of filter paper that measures ~50mm in the dimension along which the constituent compounds will spread (and just scale any observations and/or Rf calculations), instead of using longer strips, if granularity or resolution is not the primary concern? In the same vein, I would write with a lower x-height using an Extra Fine nib, to convey the same amount of information (and meta-information, such as shading and sheen exhibited) pertaining to an ink, in a smaller area than someone who writes (and prefer to write) with a Broad nib.

 

 

As far as using a longer strip:

 

There is a concept in all chromatography called plate height. Essentially a "plate" is a region of separation. There's also a concept called resolution, which is effectively the ability to separate two compounds. In instrumental techniques, we can measure these values fairly easily, but that's getting beyond what you want for what you're doing. On a conceptual level, though, the more theoretical plates in a column(column in this case is your strip of paper), the better the resolution. You can increase the number of theoretical plates by doing something to make each smaller(which can include changes to the stationary phase) or to simply increase the distance over which it is separated-i.e. using a longer strip of paper. The latter is not a perfect solution, though-at least in a simple chromatography system like this, increasing length does necessarily increase time. Longer separation time causes band broadening which decreases resolution(longitudinal diffusion, or b in the Van Deemter equation if you really want to geek out). So, all I can suggest is try-longer strips may give you better separation of dyes at least up to a point.

 

By all means use the smallest sized spot you can. There again, this goes back to chromatography theory that you want to introduce your sample onto the column using as concentrated of an area as possible. In fact, in gas chromatography, we often use post injection techniques to accomplish just this, and in high pressure liquid chromatography the sample is put into a small loop of tubing that is "switched" into the plumbing and flushing the sample out. In thin layer chromatography, we usually use a glass capillary, and are careful to use as small of a spot as possible. If you wanted to get fancy, I'd suggest even forgoing using a fountain pen at all, but instead using TLC spotting capillaries, but that's most likely overkill.

 

Strips do exist-they're called paper chromatography strips. Whatman 3MM CHR.

[A Smug Dill]

As far as using a longer strip:

Strips do exist-they're called paper chromatography strips. Whatman 3MM CHR.

 

Thanks.

 

I saw those listed on Amazon.com, when I was looking hard at this in the past few weeks, but Amazon itself doesn't sell them, and those third-party sellers on Amazon Marketplace won't ship the products to Australia (never mind that it probably wouldn't be economical to do so even if they would ship them). They aren't listed on Amazon.com.au and eBay, as far as I can see, and I'm probably just not keen enough to look at local suppliers whose primary clientele are professional laboratories and who charge accordingly. Trying to get clear ammonia solution (to dilute) for pen cleaning was difficult enough, as it isn't something I can just get from the supermarket or the local pharmacist; I ended up travelling way out and buying a large bottle (it had to be either 5L or 20L) from an industrial supplier that sells to dry cleaning businesses, probably at fivefold the per-unit-volume cost Americans expect to pay buying from Walmart, and if I tried to source it from lab supplies retailers it'd be fivefold that yet again. So, I'll just make do with what I can get on eBay relatively easily, in the name of hobbyist pursuit as a rank amateur; the more money I have to sink into the project, the less likely I'll want to share any information coming out of it.