Who makes the best ink in terms of purity, dye quality, etc?

Uh oh, looks like another religious discussion is being solicited!

Yeah, this is kind of a mix of tech characteristics and personal opinion, so we are going to see another long, passionate thread.

Best quality for me is; good flow, dye and harmless, non clogging ink. Answer : Waterman any color. Very vintage producer of inks, with a limited range, but they ones they have, hey, they just can't be beaten!. And if you want a broader palette....they even mix well. (Just a personal tip). Widely available, good price and even reputed nibmeisters in this forum recomend it. It's been used in my home before I was even born and there are a couple of Parker 21 that wittness that is a heck of an excellent ink.

Well, we never had a thread on quality, only color and properties on paper. How "good" is the liquid itself and the particles being soaked within?

Never had a thread on quality? What do you consider the threads about permanence, lightfastness, dye settling /separation issues... etc as? This is all related to quality.

For the kind of technical information you seem to be seeking, the ink manufacturers likely need to be contacted and dye information and ingredient lists obtained. With that information, you can begin to assess the purity of the dyes used via publications like the Colour Index, produced by the Society of Dyers and Colourists.

I like to dabble with watercolours, and in the vast realm of artist quality paints there are dozens of variations of paints based on a single pigment. In some cases, there are only one or two manufacturers in the world of that single pigment. If all the paint companies are buying that pigment and using it to make their paint, the products all have similar behaviour and lightfastness ratings etc. Dye products will be very much the same.

The big difference between most fountain pen inks and most artists paints is that much more information is available about the qualities of artists paints, because permanence is a relatively more important concern for artists than it is for fountain pen users, at least at the current time. Most fountain pen inks are a proprietary product about which practically no information is available concerning formulation.

Answering the OP's question is difficult, because different users may have different ideas about what constitutes quality.

Has anyone ever written a treatise for Fountain Pen Network on just exactly what ink is, and what its qualities are?

Well, I once put Ivory soap in my pen.
I believe that it was the purest ink I have used yet---99.44% pure.

Actually, what is meant by "ink purity"? (I cannot think of the last time I received ink that wasn't mostly ink!)

What qualities of a dye are considered important when it comes to ink?

If ink is like most mass-produced chemicals, and it is, it's not just about the ingredients. There is always ingredient variation, so it is also quite important how the manufacturer accepts these variations to make a product that meets whatever specifications are to be met.


Which brings me to my question: what specifications do FP inks need to meet?

Okay, I think I bit off more than I need to chew. I guess whatever works works.
What brought this up was when Nathan from Noodlers said that inks of the past were better/higher dye content, etc

Depends on properties, I think. The ability of so many high quality inks to survive in the market suggests that equal quality can survive under many guises. I doubt less attention goes into PR inks than Noodler's inks, but the companies seem to have different goals in what the inks deliver. I think the inks from the bigger pen companies are a bit boring, though.

Private Reserve!