Here’s Why Ballpoint Pens Blot

Ballpoint pens are convenient and ubiquitous, and you probably use one nearly every day. However, that doesn’t mean they’re without their issues, and you may have had a good shirt ruined by a blot from a ballpoint pen. Here’s why ballpoint pens blot.

Ballpoint pens blot primarily because of heat, making their oil-based ink less viscous, causing it to flow too easily. Capillary action from paper or fabric adds to blotting. Because they are delicate, damage to ballpoint pen tips from wear on paper or from being dropped can leak ink.

Understanding why ballpoint pens blot is the first step to preventing this problem and giving you one less thing to worry about. Now you can carry one and use it without worrying about it blotting.

The Causes Of Ballpoint Pens Blotting

There are two leading causes of ballpoint pen blotting: warming of the ink that results in it becoming less viscous and flowing more quickly, and mechanical damage to the rollerball mechanism at the tip of the pen that results in ink leaking out around the ball.

Let’s examine these two significant causes of ballpoint pen blotting so that you can better understand why the problem occurs. We’ll also give you some care tips for looking after your ballpoint pens to ensure that the problem does not happen.

What Happens When Ballpoint Pen Ink Warms Up

Ballpoint pen ink is a viscous oil-based liquid or paste. Viscosity refers to a liquid’s thickness, with a viscous liquid being one that does not flow easily like water but is thick like molasses.

Ballpoint ink contains around 25 to 40 percent dye to mark the paper, fatty acids (oils) that lubricate the ball tip during writing, and solvents such as benzyl alcohol or phenoxyethanol allow the mixture to flow smoothly and dry quickly.

Hybrid inks contain extra lubricants to make writing smoother and speed up drying time.

More viscous ink dries faster but requires more writing pressure.

When you put a ballpoint pen into your shirt pocket, your body’s heat causes the ink in the reservoir to warm up and become less viscous.

It then flows more quickly than it is supposed to during writing, and gravity draws it to the end that is downward, from whence it flows out onto your clothes, causing an inkblot. This flow happens even if the pen is well-capped.

Because the fabric of your shirt also creates capillary action, like paper, which causes the ink to flow, the blot will tend to spread.

Capillary action, also known as capillarity, is the process whereby a liquid moves through something solid, either in a tube (such as a blood capillary) or in a material filled with tiny holes, such as paper or cloth.

Capillary action occurs because the forces of cohesion, adhesion, and surface tension combine to allow the liquid to creep through the spaces of the material.

Warm environmental conditions can also cause blotting while writing, particularly with poor-quality ink.

Mechanical Defects That Cause Ballpoint Pens To Blot

In ballpoint pens, an ink reservoir feeds ink to tiny tungsten carbide (originally steel) ball held in a brass socket at the pen’s point (hence the name, ballpoint).

As capillary action delivers ink to the ball, the writer’s hand guiding the pen over the paper causes the ball to spin, providing ink to the paper and creating the ink line of writing. The mechanism works similarly to a roll-on deodorant, only on a smaller scale.

When you aren’t using the pen, the ball sits tightly against the ink reservoir and prevents the ink from drying out.

Because the pen’s tip that holds the rollerball is made of brass, and because you do so much writing, the tip can wear on the paper and get scratched. Ink can leak out around the scratch if this happens, causing blots.

Such wear will occur if you hold the pen at too great an angle (too close to horizontal). It is preferable to have the pen at an angle greater than 60 degrees from the flat when writing, to keep the brass tip from wearing on the paper.

Because the pen’s tip is a delicate structure with a tiny ball held inside a thin brass tip, it is vulnerable to damage. If you push the pen into an object to create a hole, you risk damaging the tip, leading to blotting.

Similarly, if you drop the pen onto its tip, it will get deformed and vulnerable to blotting.

Sometimes, blotting is due to manufacturing defects. Poor quality pens may not be designed precisely enough to prevent ink from leaking out and will tend to blot. Opt for pens that are well-designed and manufactured. A good cheap option is the justly famous Bic Cristal.

How To Look After Your Ballpoint Pen To Prevent Blotting

Keeping your pens in the correct position goes a long way toward preventing blotting. Keep them stored horizontally at home or horizontally in a case if carrying them around.

If you have to store your pens in a pocket, keep them vertical and nib-up to minimize the chances of ink flowing onto your shirt. If it is a hot day, rather don’t store pens in your shirt. The ambient temperature plus your body heat is likely to cause trouble.

When storing pens at home, keep them cool. Heat makes the ink less viscous, but it can also cause the air inside a pen to expand, pushing ink out. Keep pens capped if they have caps or retracted if they are the retractable type.

Don’t use your pens to make holes in objects (unless it’s a dire emergency), and try not to drop them.


There are several different causes for ballpoint pen blotting, which have to do with the composition of the ink and the delicate structure of the pen’s tip. Keeping your pens in cool conditions and treating them with care should prevent most problems.

With care, your ballpoint pens should give you many miles of blot-free writing time!

Similar Posts