When we say you can use "any ink or paint" in our pens, we mean you can use any ink or paint commonly used as a drawing liquid. We configure our pens to hold and deliver a wide range of inks and paints used for drawing and writing. We can modify our pens for less popular media, such as lacquer and alcohol, but most people don't use those for drawing and writing.

For example, if you use enamel and lacquer — on the thick end of the spectrum — they will flow for a minute or two and then stop. If you're using our Pump Pen, you can get enamel and lacquer to flow a bit longer, but sooner or later, these thick paints will slow to a crawl, and you'll spend time cleaning them out of the pen.

If you use alcohol-based inks — on the thin end — they can flow quickly out of the pen into a puddle and make a mess.

>It's better to view your choices from the range of liquid media offered for commercial sale and divided into three categories:

• Fountain pen inks
• Drawing inks, including India ink and calligraphy inks
• Drawing paints

These inks are designed to be used in traditional fountain pens. They usually run thin, and when you draw with them, the line tends to disappear over time. Most fountain pens are designed with narrow channels that modulate the flow so you get a nice steady line with no fluctuations. The ink must be thinner so it can flow through the tight spaces without clogging.

There have been a lot of recent improvements to fountain pen inks, especially with the discovery of aniline dies. Since most fountain pens are used for writing, and writing is the most popular activity with a pen, this is the largest category of liquid media. It is also the least interesting to the majority of our users, who prefer inks and paints that leave a strong mark and are designed to remain visible for 100 years or more.

• There are hundreds of brands for this type of ink since it is so popular, although some brands are identical and just rebranded.

Drawing Inks

Drawing inks, including India ink, are thicker than traditional fountain pen inks. The thickness is derived from two sources: the material that comprises the ink and the additives that help the material particles disperse and adhere to the substrate or surface, such as paper. Ink material varies. Traditional India ink contains particles of carbon that remain dark black for a long time. Additives include shellac and gum Arabic among, designed to bind and adhere the dried ink to the substrate.

Manufacturers include Winsor and Newton, Higgins, Speedball, Dr. Ph. Martin's, and Noodler's among many others. You will find these brands in well-stocked art and craft stores.

Drawing Paints

Drawing paints consist of acrylic paints and other liquid polymer combinations. The term "acrylic" derives from "acryl", which is short for "acrolein acid". It is a glassy thermoplastic produced as a solid or liquid. Acrylic paints are usually thicker than drawing inks, but you can find acrylic paints ready to use for fountain pens, such as Golden Hi-Flow Acrylic. The terms "acrylic paint" and "liquid polymer combinations" are used interchangeably.

Because acrylics are also used for painting, you have a much larger selection of choices. You can add various types of thinners to acrylic and polymer paints so they flow more easily, and you can add thickeners that slow down the flow. This category includes lacquer and enamel. So if you thin them a bit, you can use them in our pens. Manufacturers include Golden, Daler-Rowney, and Liquitex, among others.

You should feel free to use the ink or paint in our pens that you want to use. It's fun to experiment with all your choices. Inks and paints are colorful and individual, and new combinations appear all the time. The choice is yours.

Cleaning Inks and Paints

No matter what you use, keep your pen clean. We claim nothing will plug up our Fountain Pens or Pump Pens. That remains true. What we mean is "plug it up permanently".

Some inks and paints are easier to clean than others. Inks and paints can dry out and stick to the inside wall of the pen, but you can always clean them off, even if it takes a bit of scrubbing.

You don't have to clean our pen every time you use it. You can set it down for an hour, a day, even a week, then pick it up and continue. The ink or paint might ooze out depending on how you store the pen. The longer you let it sit containing thick ink or paint, the gummier it will get. But you can usually clean that off with one swipe of a cloth or towel.

The basic rule is that the cleaner you keep the pen, the better it will work, which is one person's opinion based on experience.

Feel free to reply with your feedback and comments using support@ackermanpens.com. The more we share, the more we know.

Flow Rates of Inks and Paints

The flow rate of inks and paints is a popular topic of discussion among people who use fountain pens and pay attention to the inks and paints they use. The single term "thickness" comes up often. For example: "India ink is thicker than fountain pen ink." But thickness is only one factor determining the rate at which ink or paint flows through a pen.

From Wikipedia: "The viscosity of a fluid is a measure of its resistance to deformation at a given rate. For liquids, it corresponds to the informal concept of "thickness. For example, syrup has a higher viscosity than water. We will use "flow rate" as the topic for this article.

The flow rate of ink or paint through your pen is important because you want an unbroken flow that is not too strong. You always need ink ready to flow at the tip of your nib. You don't want ink to drip off the nib because the flow is too strong, nor do you want the ink to stop flowing mid-line or mid-word. You also want the ink to speed up when you need more and slow down when you need less.

You expect a lot from a static device that doesn't really do anything. There are no moving parts in the front end of a pen to help adjust the flow and compensate for changed conditions. 

Compare this to feeding gasoline to a car engine, which uses complex and expensive machinery that lets you control the flow precisely. Not so with a pen.

The term "thickness" when applied to liquids is called "viscosity" and describes the state of a liquid as being thick, sticky, and semifluid in consistency due to internal friction. Zebra Pen provides a good layman's introduction as viscosity applies to fountain pen ink.

Viscosity is a primary determinant of the flow rate of ink. But there are others, such as surface tension, the angle you hold the pen, the warmth of your hand, the size of the internal apertures through which the ink must flow, ambient air pressure, plus other constraints and forces.