Two Invisible Inks Briefly Compared

[A Smug Dill]

I placed an order for a bottle of Noodler's Blue Ghost back in March, when I saw it was offered at a good price. However, the retailer was unable to fulfil the order right away (and that's understandable), and when their order of inks came in from the US a month later but there was no Blue Ghost in sight, that was the last update I got, even though I told the staff there I still wanted a bottle of ink and wasn't letting them off the hook so readily.

 

Then, I saw this other invisible ink in 18ml bottles on eBay, with no brand name or detail -- including whether it's safe for fountain pen use, much less whether it's "bulletproof" -- for just a few dollars and came with a tiny UV torch, I bought one just for the hell of it, even though the per-millilitre unit price is 220% of that of the Noodler's ink.

 

However, since then I was able to order a bottle of Blue Ghost sold and delivered by Amazon US for a reasonable price, so I had confidence it was actually in stock. That order was delivered yesterday. (I have since cancelled my original order from the first retailer and got it refunded.)

 

I wonder how many of us here would bother with getting two different invisible inks, even though we wouldn't blink an eye about ordering the sixteenth "different" shade of blue, or even coloured two inks that are supposed to dopplegangers of each other?

 

Anyway, so here they are:

 

 

Both are equally invisible on the page under normal lighting conditions, of course.

 

 

Once dried, you can write on top of it with coloured inks, with minimal interference (feathering, etc.) and certainly not every place where two ink tracks cross, but there is nevertheless some with either of the invisible inks if you look closely.

 

 

Neither of the inks are what I'd call waterproof (but they are fairly water resistant), which I guess precludes them from being "bulletproof". This is what they look like after a two-hour soak:

 

 

Even though the Wing Sung 3008 into which I filled the Turritopsis ink has an EF nib, and the Sailor Profit Junior that holds the Blue Ghost ink has a MF nib, I don't expect the difference in the line widths to be substantial. What I'm finding, though, is that Blue Ghost has more of a tendency to spread once laid on the page. The paper in the Maruman m.memo DMP-A7 notepad I used there is not apt to be absorbent, and I was careful to cover the rest of the page with a paper napkin while I wrote, so as not to compromise the paper coating. (I can see from the washed out writing how fine or broad the contact surface from the nibs are. (Yes, I can test them properly against each other with a different ink, or even swapping the inks around in the pens, but right now I don't feel like cleaning them and flushing ink down the drain.)

 

Between the lack of evidence to support the claim of being "bulletproof" (but I really should look up if there is any word definition and test procedure published by Noodler's), and the tendency for the lines to be broader than they need to be because of the spreading, I must say that the Blue Ghost ink has disappointed me, if so no-name ink (actually, there is one in 3-point Flyspeck on one side of the bottle label: Tramol) from China proves equally as water-resistant but seems to work better. Now, of course I don't actually trust or assume the Turritopsis ink to be perfectly fountain pen safe, so I'm not going to put it in a $200+ gold-nibbed pen, but then I'm not inclined to do so with Blue Ghost (or Noodler's inks in general) either; a Sailor Profit Junior which cost me twenty-odd bucks to acquire is about as much as I care to risk on a lark.

 

Still, writing with invisible ink is fun, and more fun (and much easier!) when my order of UV bulbs for my desk lamp comes in. I can't wait to show the young'uns at the next Christmas family gathering, and I've already put in an order for some non-fountain pens that also dispense invisible, fluorescent-under-UV-light ink to give them -- and a couple of big UV torches for their parents; I'm sure they'll need those.

Edited July 12, 2019 by A Smug Dill

[inkstainedruth]

Thanks for the comparison. I didn't realize that there *were* any other "invisible" inks on the market besides Blue Ghost (which I like for using in a notebook where I keep my passwords because that's the sort of thing an ink like that is good for). I limit its use to one of the Noodler's Charlies, because I really don't use it all that often (and accidentally bought a 4-1/2 oz bottle when I forgot that I had a 3 oz. bottle of the stuff.

Of course the hardest part is keep track of the notebook and the UV flashlight (and making sure that the batteries in said flashlight are still working). I was actually surprised, though, as to how easy it is to BUY a UV flashlight (most big box stores hardware stores like Lowes or Home Depot carry them, as well as sometimes at Walmart); the lights are mostly used to find where your pet has had an "accident", BTW.... Using them with invisible fountain pen ink is just an added bonus....

Ruth Morrisson aka inkstainedruth

[A Smug Dill]

I noticed, on another test sheet, that the inks glow differently under UV light. It's hard to describe, and even harder to capture with my camera and my current lighting set-up. The following photos show you that they appear different:

but neither quite match what I perceive with my eyes. Blue Ghost, once dried and given enough time to absorb sufficient energy(?), appears more green than Turritopsis, which appears more of a powder blue. A bit like in the bottom photo immediately above, but the glow is far more intense; and, of course, more bluish light was reflected off the unmarked areas of the page, not quite as violet as in the photo above it, but certainly not against as dark a background.

 

Or, looking at the photo of the bottles under UV lighting at the top, the colours of the inks you see inside the demonstrator pen barrels are very close to what I see on the test page -- but in reverse! Confusing? When the ink tracks are first laid down with the pens, Turritopsis is greener than Blue Ghost, just like they appear in the pen barrels. However, once dried on the page, that is reversed. I don't know why.

By the way, I pulled the nib out of the Sailor Profit Junior to adjust the tine gap and make it rather drier than before, and now I can actually see the nib lay down very fine lines of Blue Ghost with sharp tails (that I like, especially when writing Chinese in the kaishu script), and observe the line width grow over a few seconds, which causes the pen strokes to become rounded and lose much of the 'character' I try to inject into them.

Edited July 12, 2019 by A Smug Dill

[bobje]

Opening an ink thread on FPN and discovering an analysis of two separate brands of invisible ink is one of the great joys of this forum. Thank you, Dill.

[KaB]

Opening an ink thread on FPN and discovering an analysis of two separate brands of invisible ink is one of the great joys of this forum. Thank you, Dill.

 

indeed it is

thx

[Fearless]

I just got Blue Ghost... no idea what I will put it in, but it sounds to me like a Fine nib will be okay. Not really something to “show off” except that it exists under the black light.