Test Your Ink: Stability
Ink stability is another important aspect of performance. When ink sits idle in the cartridge, there's a chance its components could separate over time. The result is like an oil and vinegar salad dressing you need to shake before each use.
You can test the stability of ink using thin layer chromatography (TLC). Chemistry students often use this technique to separate mixtures, and it's an easy way to make sure that ink exists as a stable mixture. Unfortunately, you'll need some special equipment: namely, a silica TLC plate. You can find that by shopping online science supply shops or rummaging around in your local university's chemistry lab.
The test itself is pretty simple.
- Place a small drop of ink on the TLC plate.
- Drop the plate into a dish with a small amount of water. The water level shouldn't be above the dot of ink.
- Check the results every five minutes until 30 minutes pass.
If the ink is stable, you'll see little to no separation on the TLC plate as the water is drawn through capillary action. The animation above shows an extreme example of ink separation from a black permanent marker.
We did own our TLC test to show you what a good ink should look like. The ink on the right is resisting separation, which is an indicator of stable ink.