Author Topic: Iron Gall Ink Degradation over time?  (Read 46 times)

Offline Karl H.

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Iron Gall Ink Degradation over time?
« on: September 10, 2019, 10:08:28 PM »
Hi All,

I have a jar of Old World Iron Gall ink which I used for a project a few years ago.  I hauled it out for a new project (I'm looking for the ink that best does what I want), and when I began writing with it instead of the deep blue-black color I got last time, I got this almost transparent, grayish fluid... barely qualifies as an ink.  This is after vigorous shaking and stirring of the ink.  It also seems like there might have been some evaporation since I last used it; it was almost full when I put it away; now it's about half-full (and the cap was really tight; had to use a channel-loc plier to get it open.)  It's also entirely possible that I used more ink than I remember, though I don't think so.  Is this normal/typical behavior for iron gall ink?  And in any event, is there any way to 'revive' the ink I have, or is it just gone and needs replacement?  Thanks!!

Offline Ergative

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Re: Iron Gall Ink Degradation over time?
« Reply #1 on: September 11, 2019, 05:08:09 PM »
Yes, iron gall ink is not shelf-stable. There are two ways it can go bad. One way is 'mothering', which happens when the ink generates a gelatinous mass that congeals at the bottom of the bottle. The other way is by precipitating, which happens when the ink generates a grainy sludge that collects at the bottom of the bottle.

I have been told, but have not confirmed through my own experience, that when your ink 'mothers' (gelatinous mass), you can revive it by adding distilled water, and it will turn liquid again. However, when it precipitates (grainy sludge), it's done.

If your ink bottle is plastic, it may have breathed a bit, and allowed ink to escape through the bottle itself, no matter how tight the cap was on.
Clara

Offline K-2

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Re: Iron Gall Ink Degradation over time?
« Reply #2 on: September 11, 2019, 07:01:46 PM »
Yes! -- furthermore, that grainy sludge is the actual iron of "iron gall ink" that has precipitated out of the solution.  Some iron gall inks are effectively transparent when they're "fresh", so manufacturers like Diamine, for their Registrar's Ink, put a light blue dye in it so that you can see what you're writing, but the real dark blue-black color comes from the iron in suspension binding to the paper and then oxidizing as it's liquid holding medium evaporates.

The microscopic iron particulates are dissolved and held in suspension by the gallic acid (the gall in "iron gall ink").  When that evaporates or breathes out of your plastic bottle, since it's molecularly smaller than water, the iron will fall out of suspension and form that grainy sludge at the bottom, and all that's left is your lightly tinted grayish water.

Science!

Offline Karl H.

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Re: Iron Gall Ink Degradation over time?
« Reply #3 on: September 11, 2019, 09:54:17 PM »
Aaahhhh!  I LOVE science!  I don't mind that this happened (it's a very old formulation, after all, and not surprising that it isn't 'forever' ink...), I don't like not knowing what happened or why.  Your explanations clear things up nicely.  My ink seems to have precipitated, as there is indeed a precipitate at the bottom of the jar; it can be dispersed by mixing, but it settles out again pretty quickly.  It's still quite liquid, so I don't think it "mothered."

Thanks for the quick and informative replies!  I may have to learn to mix up my own batches as needed, since it doesn't store well.