Pen Ink Chromatography

Use simple paper chromatography to separate the color components in fountain pen inks. A small ink line on chromatography paper or paper towel is developed with water so the dissolved dyes travel different distances and reveal hidden color blends.

1. Gather materials: chromatography paper strips (or white cone coffee filters cut into strips, or paper towel), small clear cup or jar, water, clips (paper clip or binder clip), pencil, ruler, scissors, several fountain pen inks or samples, optional glass dip pen or cotton swab.
2. Cut paper into strips about 2 cm wide and 8–10 cm long. With pencil (not pen), draw a light baseline across each strip about 3–4 cm from one end and label the strip with the ink name.
3. Apply ink: use a dip pen, cotton swab, or the bottle’s dropper to draw a single, narrow ink line along the baseline. Avoid flooding the paper; one slow pass is enough.
4. Add a small depth of water to the container (just enough to wet the bottom ~5–10 mm of a strip).
5. Suspend the strip so it hangs freely: clip the top of the strip and rest the clip across the container opening so the paper does not touch the sides or bottom.
6. Check the water level before immersing: the ink line must remain above the water surface; only the blank lower edge should touch the water.
7. Place the strip in position and let the water wick upward by capillary action. Watch as color bands separate and move at different speeds.
8. Allow development to continue until the water front nears the top of the strip or the colored bands stop moving (about 1–5 minutes, depending on paper and strip length).
9. Remove the strip, immediately mark the water front with pencil, and lay it flat to dry. Record the ink name on the dry strip for reference.
10. Repeat for additional inks. Optional: compare brands or similar hues side-by-side on separate, labeled strips.
11. Alternative quick test (paper towel method): place a drop of ink on an absorbent white paper towel, then add water drops onto the center of the spot one at a time until the colors stop spreading; allow to dry and label.

How to Do Your Own Ink Chromatography (It’s EASY!) - JG3 Reviews:

Ink chromatography - Dr. Steve Griffiths:

📄 Ink Chromatography - Well Appointed Desk: https://www.wellappointeddesk.com/2020/07/ink-chromatography/

• Compare tap water vs. distilled or bottled water if your tap water is very hard; note any differences in separation or band clarity.
• Try different papers (chromatography paper vs. coffee filters vs. various paper towels) and rate which gives the sharpest separations.
• Test “similar” ink colors from different brands to see if their underlying component colors differ.
• Run longer or shorter strips to see how development time and distance affect the appearance of faint components.
• Create a reference library: mount dried strips in a notebook with ink names, date, and notes on paper and water used.

• Do not ingest inks or use vessels later for food or drink; keep experiment items separate from kitchen use.
• Avoid skin and clothing contact with concentrated inks; they can stain. Wear gloves or wash hands promptly.
• Use scissors carefully when cutting strips; supervise young students.
• If testing with isopropyl alcohol instead of water (optional), keep away from flames, use minimal amounts, and ensure good ventilation.
• Clean spills immediately to prevent staining surfaces.

• Why do some colors travel farther than others on the same strip? (Different dye components vary in solubility in water and in how strongly they interact with the paper, so they move at different rates.)
• What does it mean if two inks look identical when written but show different chromatography patterns? (They are formulated with different dye mixtures that produce the same apparent hue on paper.)
• How would hard, mineral-rich tap water potentially change your results? (Dissolved ions can alter dye solubility and paper interactions, sometimes reducing separation clarity or shifting band positions.)
• Why must the ink line start above the water line? (If submerged, the ink dissolves into the reservoir and streaks or washes away instead of separating along the paper.)
• How could you make results more comparable across tests? (Keep paper type, strip size, water depth, starting line height, and development time consistent and label everything.)