For the fountain pen, this is one of the big factors in performance. There are numerous brands, and many have their own unique characteristics. Nnext to the passion for a particular pen, the next most important topic to those who use pens is ink.
The overall writing experience is a combination of the pen and how it sits in your hand, the nib and its own writing charactertistics, the paper and how it interacts with the ink, and then the ink itself.
I hope the reviews are helpful, but in the end, your experience with a particular ink depends on the pen and paper you use.
I use a wide range of ink, and some of the inks move into my Inks of Note category - the inks I tend to use the most.
Fountain Pen Ink
What is fountain pen ink? It is basically water, dyes for colour, additives to stop things growing in the ink, and chemicals to help with viscosity and to control how the ink spreads when it comes in contact with the paper.
Pen Companies and Brands of Ink
A common question asked is if it is OKAY to use a different brand of ink than the pen. Yes, and what you will find is some brands just don't perform as well in some lines of pens.
As an example, when I visited with OMAS they said they establish the specifications for the OMAS brand of ink to be compatible with the characteristics of their feed systems.
So feel free to try different inks. Be prepared that some will not work as well. Be cautious of some colours of inks (reds and purples especially) that have higher staining.
Keep the ink in your pen current. If you are not going to use a pen for a period of time, flush the ink out. The best way to flush your pen is to expel the ink, and the draw up and expel some water.
Only Use Fountain Pen/Writing Ink
Avoid inks made for calligraphy as they have pigments and have different characteristics from inks made for fountain pens.
Bottle Design is Important
Not only is the composition of ink important, but so is the design (shape) of the bottle. Ink is expensive, so it is important to be able to use it all.
This is an issue especially important for those using pens with large nibs. It is important to have the nib fully submerged in the ink so that only ink, and not ink and air is drawn up into the pen.
I particularly like ink bottles with shape that allows the nib to get right into the ink. Either a vertical design, or a bottle with a filling well (indent) helps. The classic Montblanc bottle is a good example of a bottle with an indented filling section.
There are bottles that are designed for your desk and those that travel well. I like the multi-sided OMAS ink bottle on my desk. It is big and sustantive enough that it sits on the desk and is not knocked over too easily. I can slant the bottle on its side for a good fill. But in my leather briefcase the large round size of the bottle is a bit bulky. So I keep other bottles specifically as they fit nicely into the pouch of my briefcase.
Inks are Expensive
Buying a bottle of wine or a bottle of ink as a gift is almost the same price point. Yet the bottle of ink is so much smaller!
Inks are expensive. Over the past year the prices of ink has continued to climb. My Pen Views column, from time to time I have compared the price of inks.
In 2012 I looked at the size and price of a range of brands. The cost per ounce ranged from $4.72 for Diamine Ink to up to $20.59 for iroshizuku. Tood bad I like iroshizuku ink so much!.
Waterman, Pelikan, Delta, OMAS, Visconti are all brands that quickly come to mind when I think of inks that work in a wide range of pens. These are all what I consider inks at a basic price point. Other lines of inks can get very costly.
Noodler's, Private Reserve and Diamine are another groups of ink that I have used extensively and come in very vibrant colours.
There are ink mixing kits that can be bought. Mixing inks is done with caution and you may or may not have luck. Mixing inks of different colours and different brands can have unexpected results in how the chemistry interacts.
In 2011 Platinum issued an ink mixing kit. The inks were advertised as being specifically different from other inks in they are made to be mixed. As they said, "Mix free ink does not harden when it is mixed, and the ink does not clog up in a nib." That gives you an idea of what can happen with some inks as a result of mixing inks where there is a chemical imbalance in the final product.