Not a curiosity. I have emailed several ink and pen&pencil production companies and until now I didn't get any kind of logical answer. The question is why most pens contain blue color rather than any other color? Is there any secret behind it being blue? Does blue color have any special features or additional characteristics that makes it used over any other colors?

I searched several suitable places to ask this question and I found that UX StackExchange is the best place to post such a question.

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    I guess it's probably for historical/resources-availability reasons rather than for UX. – Alvaro Nov 16 '16 at 16:11
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    @Dipak, There are UX reasons but I would say the main reason pens are still mass-produced with blue ink has not to do with those, at least for the UX reasons stated in the answers till now. – Alvaro Nov 16 '16 at 18:44
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    I dispute the premise that "most" pens are blue. Black seems to be just as common as blue. – David Richerby Nov 16 '16 at 20:09
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    The question appears to be based on a non-validated assumption and is also likely not about UX at all but rather historical manufacturing reasons. – DA01 Nov 16 '16 at 20:30
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    I'm voting to close this question as off-topic because it's about product manufacturing, not UX. – DA01 Nov 16 '16 at 20:30

OK, I have found what it occurs to me as the most likely reason: a combination of technical issues dealing with gall and ferro-gallic inks on fountain pens and knibs, extensive chemical testing and research which ended on official instructions from several governments, including Prussia (the famous Prussian blue) , UK and United States. Then market adapted to this, based on new discoveries like aniline and synthetic French ultramarine

This can be found in a book from 1904 by David Carvalho, Forty centuries of Ink or A chronological narrative concerning ink and its backgrounds

It explains in great detail the whole process to obtain inks, how different inks where needed for pens and much more, a really interesting lecture. But even more important: UXers will be shocked as how this author researched based on nowadays common UX techniques.... more than 100 years ago. Furthermore: the reasoning behind the inks selection was made based on user needs, with a wide array of user cases

For those interested on the OP's question, you can skip directly to around page 150 and further

As a curiosity...

A little known fact…Charles Dickens increasingly wrote in Prussian Blue ink towards the end of his writing career. His famous last novel the Mystery of Edwin Drood is almost entirely written in Prussian Blue ink.

Disclaimer: I obviously didn't read the whole book!

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    You say "the reasoning behind the inks selection was made based on user needs" but don't state what that actual reasoning is. – DA01 Nov 17 '16 at 1:51
  • Because it takes at least 30 pages in several diffrent chapters. Just read the book in the link, it can't he copy-pasted – Devin Nov 17 '16 at 2:21
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    Umm...OK, but then it's not really an answer. Just a link. – DA01 Nov 17 '16 at 2:45
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    I gave an answer, you can read the link that supports it, same as all the other answers . Do you want me to explain you the whole theory of each discipline of UX every time I give an answer? Btw, the most voted answer so far was made after a comment I made and it just copy pasted a link (not that Kristyan needed it, his answers are always good and he'd probably answer this without my comment). Anyways, thank you for your downvote on a thoroughly researched question, it speaks tons. – Devin Nov 17 '16 at 3:09
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    "just read the book" just isn't a great citation. – DA01 Nov 17 '16 at 6:54

Because the first widely used ink was iron gall which had purple-black or blue-black colour.

And the color remained as a standard until today.

text written with iron gall ink text written with iron gall ink

Detailed explanation:

The pervasiveness of blue ink has to do with the type of ink that preceded the modern dye based inks.

From about the 5th century to the late 19th or early 20th century, standard ink used in Europe was iron gall ink. Iron gall ink, made from iron salts and tannic acid derived from oak galls, was superior to carbon based inks as it adhered better to parchment (i.e. didn't smear) and was waterproof.

The ink was (and is) also valued for its permanence. The color of the ink is a dark blue/black, though it may turn to a brown over the centuries. The ink does have a drawback however. The tannins in the ink are corrosive and can eat away at parchment over long periods and more quickly with paper.

In the 20th century, ink manufacturers started to develop other formulas for inks, synthesizing new dyes that would not corrode the metal parts of fountain, dip, and ballpoint pens. New inks, both waterproof and non-waterproof, were introduced and in an array of synthetic colors. Iron gall ink continued to be used for much of the century, though, particularly on governmental documents, due to its superior permanence.

As stated, the color of the ink ranges from a dark blue to a purplish black and modern usage of predominantly blue and black inks is in imitation of the older ink. Blue ink is considered acceptable in situations where other colors would not be because of the longstanding cultural precedent set by the blue tone of iron gall ink.

link to original article

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    well, OK, I mentioned this in the comment to OP, but this explains only why the first inks were blue (in western civilization, btw. Black India Ink came centuries before that). While plausible, it doesn't explain why we still use it as default, or why modern inks are that color. I could conjecture that first pens were from France and England, hence the blue was on the flag, and I'm quite sure this had some influence on ink color. But I don't know for sure . In some countries you can't use black on legal documents to differentiate signatures. So... who knows – Devin Nov 16 '16 at 17:27
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    @Devin Yes, it does, in the last paragraph of the quotation. – Kevin Krumwiede Nov 16 '16 at 19:21
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    Black ink predates this convention by several centuries: en.wikipedia.org/wiki/India_ink so the 'cultural precedent' sounds random, at best. – DA01 Nov 16 '16 at 20:35
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    It also needs to be noted that the blue ink used today is no closer to the actual color of iron gall as black ink today is. The exact same argument could be used for black pens. Finally, a link to a Reddit comment is hardly conclusive. – DA01 Nov 16 '16 at 20:37
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    @SnakeDoc could be true, but at the same time, non-repro-blue is a very different blue than the typical ink color. – DA01 Nov 17 '16 at 1:47

Nowadays the "popularity" of blue (not in every country) probably has more to do with established conventions and as an easy way to differentiate between printed text (black) and handwritten text (blue).

  • Why use dark ink?

As paper color is usually white, a dark color creates contrast. (Contrast was specially useful for faxes)

  • Why use a different color than black?

A different color than black helped differentiate an original document from a copy. Before photocopiers or printers existed copies where made with Carbon Paper, a different color than black (such as blue) could make evident the document was original. It also helps differentiate between handwritten text (or signatures) and printed one.

  • Why use blue?

@KristiyanLukanov gives the origin about the blue ink in his answer, so for centuries this has been the established color.

An interesting reference.

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    love your reference :) – Devin Nov 16 '16 at 19:28
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    The dark color point is valid. However, predating photocopiers we also had mimeographs, which were blue, which is an argument for black ink. As for it being the 'established color' that isn't true, as blue ink today is decidedly different than the blue ink referenced, and, furthermore, black ink predates blue ink historically. – DA01 Nov 16 '16 at 20:36
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    This is anecdotal, but my father is a lawyer and it's pretty common in the attorney world to use blue ink in pens to easier detect (with the eyes) when someone has photocopied a document and when it's an original. Obviously color printing has made that somewhat obsolete, but at one point in time they used it to infer things about other people, or even to use such incidents in court. – Qix - MONICA WAS MISTREATED Nov 16 '16 at 21:19

Many people choose blue ink to indicate original copies as copies made afterward would all be black. In the prison system, Sc/o's use blue ink. Unit managers use red and c/o use black.

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    "The" prison system? Which one? It seems unlikely that all prison systems in the world use the same colour coding and it seems unlikely that usage of pens in prisons is a significant driver of the market. – David Richerby Nov 16 '16 at 23:12
  • I say the Prison system because it spans multiple states. This information is true for every CCA run prison I have been in. I'm sure each state has their own policy. I am based in TN, and all the prisons I have been to conform to this standard. – Dustin Morris Nov 17 '16 at 14:34
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    So something spanning multiple US states can now be referred to as if it's the only system in the world? You do know that there are places outside the USA, right? – David Richerby Nov 17 '16 at 15:36

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