Checking the pH of inks

[SamCapote]

I read in another topic about someone saying Montegrappa inks have a pH of 3.0 to 3.3 which I found hard to believe. (I'm not saying they were wrong, just that it was hard to accept as fact/safe) So in addition to the higher pH of Baystate Blue, I was thinking of getting a reasonably priced pH meter to check inks with some ballpark accuracy. I wouldn't have much other practical use for it, so I was looking at this Extech Waterproof meter for $110 here. It has reasonable prices of calibration, flush fluids & a new tip.

 

Just wondering if you guys have any experience/recommendations using a pH meter with your inks? I'm not going to spend $300++ for the serious quality setups.

[xuan87]

i probably won't spend $110 on a pH meter too LOL! i just take what the manufacturer says as truth.

[staceyaj]

I haven't tried using a pH meter on ink. As long as water based it should work. I'd recommend something cheaper. Carolina Biological is a reputable company (Note: I'm just a long time customer.)

Edited May 14, 2010 by staceyaj

[RLTodd]

Not sure there is much significance in the issue. But, if a person wants and it won't blow the rent money, they might as well indulge.

 

FWIW, when Clark was doing "Fountain Pen Inks A Sampler" (discontinued and out of print) he measured the pH of the inks. He had Montegrappa Turquoise at pH 4.5 and the Blue at pH 2.6. No Montegrappa Black in the Sampler.

 

Interestingly, in his Pen World article reprinted in the Sampler he lists Omas Royal Blue at a pH 1.7.

 

For reference: 2.4 pH White Vinegar.

[Lloyd]

Anyone know the pH of Platinum BlueBlack?

[tfwall]

I haven't tried using a pH meter on ink. As long as water based it should work. I'd recommend something cheaper. Carolina Biological is a reputable company (Note: I'm just a long time customer.)

 

Perhaps, but that product description is almost certainly an "exaggeration". Sadly, accurate pH detection from pH 0-14 is not achievable using a single electrode. Also, detection accuracy at the 0.01 pH level is generally not realistic and certainly not achievable at this price.

 

Certainly, this looks to be an affordable pH meter and a good alternative to litmus paper for testing inks. I wouldn't put much stock in readings outside a pH 4-10 region and I certainly wouldn't worry about accuracy beyond the tenths place.

[SamCapote]

I haven't tried using a pH meter on ink. As long as water based it should work. I'd recommend something cheaper. Carolina Biological is a reputable company (Note: I'm just a long time customer.)

 

Perhaps, but that product description is almost certainly an "exaggeration". Sadly, accurate pH detection from pH 0-14 is not achievable using a single electrode. Also, detection accuracy at the 0.01 pH level is generally not realistic and certainly not achievable at this price.

 

Certainly, this looks to be an affordable pH meter and a good alternative to litmus paper for testing inks. I wouldn't put much stock in readings outside a pH 4-10 region and I certainly wouldn't worry about accuracy beyond the tenths place.

 

I had the same question, but I think it is best to talk to the companies making them to ask about extreme pH range detection accuracy with various electrodes before assuming unreliability outside of the 4-10 pH range. Monday's project.

[tfwall]

I haven't tried using a pH meter on ink. As long as water based it should work. I'd recommend something cheaper. Carolina Biological is a reputable company (Note: I'm just a long time customer.)

 

Perhaps, but that product description is almost certainly an "exaggeration". Sadly, accurate pH detection from pH 0-14 is not achievable using a single electrode. Also, detection accuracy at the 0.01 pH level is generally not realistic and certainly not achievable at this price.

 

Certainly, this looks to be an affordable pH meter and a good alternative to litmus paper for testing inks. I wouldn't put much stock in readings outside a pH 4-10 region and I certainly wouldn't worry about accuracy beyond the tenths place.

 

I had the same question, but I think it is best to talk to the companies making them to ask about extreme pH range detection accuracy with various electrodes before assuming unreliability outside of the 4-10 pH range. Monday's project.

 

If you want a reliable pH electrode for pH 3-11, most companies can provide such a electrode for ~$100. You'll need to a buy the meter itself, which can set you back another $200 easily. Expect to pay around $400 for a decent model. So, a good ink testing rig can be put together at the $500 price point.

 

Now, if you want to expand this range to pH 1-13, you'll need to start looking at electrodes like the proprietary Ross electrode. This will be around $400 by itself and can easily be double that depending on your specifications. If you hook up one of the low-end ones to the meter you purchased earlier, that'll make the set-up $800, before you start looking at calibration and maintenance supplies. So, figure that testing inks with reported pHs of 1.7 will cost you $1000 for start-up.

 

There are cheap glass electrodes out there (like the one linked to above) but they have neither the range, nor response nor accuracy to measure much outside the pH 4-10 range.

 

 

 

[bluemagister]

Ask this guy how he did it.

 

He's apparently got readings on a LOT of inks. It's interesting that Waterman inks are apparently like vinegar in pens.

[tfwall]

Ask this guy how he did it.

 

He's apparently got readings on a LOT of inks. It's interesting that Waterman inks are apparently like vinegar in pens.

 

Yes, you'll notice he wisely only carried on place after the decimal.

[WendyNC]

SamCapote, do you do much mixing of inks? I'm sitting here trying to figure out why someone would really, really want to know this and that's all I can come up with. What I'm trying to ask, without sounding sarcastic in this limited medium, is why do we care?

[tfwall]

SamCapote, do you do much mixing of inks? I'm sitting here trying to figure out why someone would really, really want to know this and that's all I can come up with. What I'm trying to ask, without sounding sarcastic in this limited medium, is why do we care?

 

That really is the only reason anyone would care. Pigment concentration, additives and surfactant loading are all much more important to ink performance and pen-ink interactions than pH.

[Lloyd]

Can accurately diluting the ink with distilled water be used to reduce the needed pH range?

 

_{I hope this isn't a dumb question (I'm not a chemist...just a mathematician)}

 

 

[tfwall]

Can accurately diluting the ink with distilled water be used to reduce the needed pH range?

 

_{I hope this isn't a dumb question (I'm not a chemist...just a mathematician)}

 

 

 

Not a dumb question at all:

 

In theory, yes.

 

In practice, it depends.

 

Many inks are buffered, which means they respond to changes in pH by acting to restore the original pH. It is important to maintain pH in certain bands prevent coagulation, precipitation and the like from occurring over time.

 

So, while in theory you could dilute the ink to bring it back closer to pH 7, the solution may in fact act to maintain pH and all you'll do is dilute the dye concentration.

[Possum Hill]

SamCapote, do you do much mixing of inks? I'm sitting here trying to figure out why someone would really, really want to know this and that's all I can come up with. What I'm trying to ask, without sounding sarcastic in this limited medium, is why do we care?

 

That really is the only reason anyone would care. Pigment concentration, additives and surfactant loading are all much more important to ink performance and pen-ink interactions than pH.

Hmm... Noodler's ink is advertised as being about pH neutral and is sometimes maligned as containing pigment rather than dye. Could there be a connection?

[tfwall]

Noodler's ink is advertised as being about pH neutral and is sometimes maligned as containing pigment rather than dye. Could there be a connection?

 

Dye character is related to pH. Dye concentration is generally independent of pH.

 

That is to say you can have high dye loading a high (low) pH. You can also have a low dye loading with a neutral pH. It is the structure of the dye, not the concentration that matters.

 

Pigments usually have no affect on pH either way as they are suspensions (heterogeneous), not part of a the solution (homogeneous). There are higher order affects based on adsorption onto surfaces, but these are generally minor effects and can be discounted in this discussion.

Edited May 15, 2010 by Chemyst

[Possum Hill]

Noodler's ink is advertised as being about pH neutral and is sometimes maligned as containing pigment rather than dye. Could there be a connection?

 

Dye character is related to pH. Dye concentration is generally independent of pH.

 

That is to say you can have high dye loading a high (low) pH. You can also have a low dye loading with a neutral pH. It is the structure of the dye, not the concentration that matters.

 

Pigments usually have no affect on pH either way as they are suspensions (heterogeneous), not part of a the solution (homogeneous). There are higher order affects based on adsorption onto surfaces, but these are generally minor effects and can be discounted in this discussion.

So you're not referring to Noodler's inks here? Can I quote you -- in a couple of years?

[SamCapote]

Let's just say that I learned long ago to not necessarily take someone's word for an item's performance and characteristics if I have my own questions, suspicions, concerns, or observations. That could be the word of an expert, a manufacturer, salesman, enthusiast, or critic. Most people have some agenda, and rarely are basic tenets, assumptions, and foundations questioned. Like someone earlier in this thread said: "i just take what the manufacturer says as truth." I have found too many cases where that has been a mistake.

 

Part of my question about pH was hearing that inks supposedly have a wildly disparate range from extreme acidic values <2.0 pH; while others significantly basic above 10.0 pH. Some have proposed cleaning pens with dilluted household ammonia that starts out with a 10-11 pH, so that's not making sense if you want to clean an acidic ink. Admittedly, you need to dillute the ammonia out to about 10%, but my curiosity was intensified when I looked up the MSDS on the highly promoted Koh-I-Noor Rapido-Eze Pen Cleaner which I posted about here. They reported a pH of 11.1, and on the bottle it says to use full strength for dried, clogged pens. So again rather than assuming it is perfectly safe to use on all pens and all inks, I questioned that. I'm not saying they are wrong, but it is amazing what you can turn up when you question fundamental assumptions. Questioning and researching tap, bottled, Brita type filter purity claims are what had me install a reverse osmosis + 4 more stages of filtration/activated charcoal in my home drinking water supply.

 

Separate from other factors (i.e. sediments, molds, ink brand reputation, etc.), I have questions about the validity and safety of ink pH extremes on the pens I have purchased. Yes, I do mix some inks which makes pH part of a compatibility factor. I have a science background which gives its own natural curiosity & geekiness, as well as some awareness of detrimental aspects of such things as pH extremes on pen hardware, etc. I have looked at the ups and downs of Kass's life at his www.inksampler.com project and some results. His entire work area being exposed to flooding damage, starting from the beginning on learning how to do pH measurements, and under extreme stresses makes me question that reliable, objective, scientific methods and his posted values are accurate. They may be, but I question them given the circumstances. There is also the useful page by Nathan on the subject here.

 

In summary, I want to know more about the inks I put in my pens.

[psfred]

A few notes here:

 

Any standard pH electrode will measure the pH of the ink quite nicely. You would probably want a micro tip combination electrode to fit into a small sample better to avoid wasting ink. You will have to pay about $250 or so, this is about the going price. A used meter on eBay will only set you back about $40, they usually last forever being quite simple. You will need new, certified standards as well, not horribly pricey. Still not going to be cheap just to "look and see".

 

Standard pH accuracy is plus or minus 0.02 SU -- it's not all that easy to measure, and is affected by temperature, fluid motion, etc. O.01 tolerance is excessive for inks, anyway.

 

Noodler's inks don't contain PIGMENTS (finely ground solids), the "bulletproof" ones contain a suspension of poorly dissolved cellulose reactive DYES, which are water soluble but in such high concentration they do not always fully dissolve. There is a difference, as pigments will NOT dissolve in water no matter how much you rinse, while cellulose reactive dyes will. The "standard" Noodler's contain much more typical dyes and are fully dissolved, just in high concentration.

 

The pH of the ink is related to the color and solubility of the dyes -- the blue inks with very low pH have dyes that will not dissolve at higher pH, and in some cases the color might change as well. A pH of less than 2 can corrode some stainless steel, although usually rather slowly. Pelikan Royal Blue as partially eaten the nib on my old Pelikan 12 -- a sort of upscale school pen -- as I assume it was used in it for years and years. Some corrosion down the nib slit, but the pen was made more than 40 years ago and still writes very nicely now with Noodler's Kung Te Cheng.

 

Rapido-eze is designed to remove dried inks containing either gum arabic or shellac, both of which tend to become quite insoluble in water when fully dried. It works quite well, and will also remove dried fountain pen inks like Superchrome which tend to form insoluble in plan water residues after sitting in pens for decades. For normal pen flushing it's overkill.

 

Peter

[tfwall]

Any standard pH electrode will measure the pH of the ink quite nicely. You would probably want a micro tip combination electrode to fit into a small sample better to avoid wasting ink. You will have to pay about $250 or so, this is about the going price. A used meter on eBay will only set you back about $40, they usually last forever being quite simple. You will need new, certified standards as well, not horribly pricey. Still not going to be cheap just to "look and see".

 

 

I'd steer clear of any micro combination electrode that you find that cheaply. It would be much better to just get one of the standard pH electrodes, like a VWR sympHony (~$150) and use the slightly larger sample sizes required. Cheap micro electrodes tend to be both fragile and inaccurate.

 

Also, be careful buying meters off eBay. Here again, cheap is no bargain. The cheaper ones tend to be of poor quality, use obsolete proprietary parts and are less accurate. If you're going to go to all the trouble to buy a set-up for testing inks, better to spend a little more and get something worth using. Avoid anything that uses tuning dials, is larger than your laptop or looks like its been around since the mid-70's, these meters have likely been surplused from public schools and are all but worthless. New student models are okay and probably preferable for the home user. These are designed to be used by high school and university students, making them fairly simple to use and more rugged. Names to look for include VWR, Thermo and FisherSci.

 

The Fisher Accumet Basic AB15 meter is a good one to start with. It retails new for ~$600, you should be able to find some on eBay for around $400. You probably will want an electrode with a BNC connector, make sure whatever model meter you get accepts that connector, most do.

 

Standards, if you can procure them from a chemical house, should run you ~$15/L and you'll need three different ones for the range of inks discussed in this thread. Get a pH 4, 7 and 11. If you have to buy from the secondary market (hobby shop, home school supplier, &c) expect to pay double and look at the expiration dates before you buy. The calibration standards are only good for about a year.

 

While you're at it, pick-up an extra bottle of electrode filling solution, you'll need it to store the electrode in. When you aren't using the electrode you need to keep the junction wet or risk destroying the electrode. The preferred way to do this is store the electrode in a vial of the same solution it is filled with, as this minimizes osmotic migration, crystallization at the junction and the like. Your electrode will probably come filled with potassium chloride and come with a small bottle of filling solution. You'll want to buy at least another 250 mL of this solution to store the electrode. Should be around $20.

 

All this will set up to determine the pH of inks from about pH 3-11. If you need a wider range, swap out the sympHony electrode for a Ross electrode (~$400) and you're set-up for pH 1-13.