Recipe for a Multipurpose, Biodegradable and Wet-Erase Blue Ink for Fountain Pens, Dip Pens, and Markers

I, like many other people, try to avoid wasting paper and also make an effort to move away from disposable stationary, which are wasteful. I wanted to formulate an ink based on the sustainable food dye blue spirulina (also known as phycocyanin). This ink has many interesting properties: it is biodegradable, non-toxic (except if you drink large quantities of it!), wet-erasable and quite cheap to make. Moreover, it can write on a variety of surfaces, like plastics, glass, ceramic, metal and paper (see image for results).

Interestingly, it can be used with an empty Copic marker, a glass dip pen and a fountain pen (I used the Muji fountain pen and the Boston Safety Pen by the Noodler's Ink Company). Keep in mind that the presence of gum arabic (here five weight percent) can potentially gunk up your fountain pen, so be sure to use a rather inexpensive one and to soak your fountain pen regularly in hot water to dissolve any dried gum arabic accumulation. Likewise, you might need to quickly clean the nib of the fountain pen with a damp cloth before your writing session, in order to wash away any dried ink on the nib that might hinder ink flow. When writing with a fountain pen on a non-porous surface such as plastic, glass or glazed ceramic tiles, be sure to give the cartridge converter piston a few extra turns in order to feed some more ink to the nib, thus avoiding hard starts when writing on these surfaces. These problems are circumvented by using the Boston Safety Pen, in which the retractable nib soaks in the barrel of pen, thus preventing clogs and allowing you to readily dissolve any dried up ink on the feed. The trick is to only partially extend the nib a little farther than the nib's shoulders when writing with the pen, such that there is greater air/ink exchange, resulting in increased flow of this relatively viscous ink. This is particularly true when writing on non-porous surfaces, as there is then no capillary action stemming from the writing surface to assist with the ink flow.

The ink holds its color for about 2 months (see the attached stability test scan), before leaning towards the green, while still being saturated enough to be usable after 4 1/2 months. You might be interested in crafting your own reusable notebooks and perform Optical Character Recognition (OCR) on your handwritten pages with ScriptReader! Check out my github repos for PrintANotebook and Scriptreader for more details. It is worth mentioning that the ink performs very well with the Muji fountain pen on cheap 20 lb printer paper, with minimal bleeding and feathering being observed (see the enclosed images). As a note of caution, please keep in mind that this ink is not of archival quality and should therefore not be used for official purposes.

This recipe gives about one fluid ounce of blue ink. For this project, you will need:

Equipment:

- A centigram scale (0.01 g), three spoons and three weighing papers for weighing out the gum arabic, sodium ascorbate and phycocyanin.

- A small plastic container for making the gum arabic solution. It needs to be light enough to use on your scale (as you will weigh out a certain amount of hot distilled water into this container), yet able to contain at least 30 mL (or around 1 fl. oz.) just to be safe.

- A microwave-safe mug for heating the distilled water up to a boil in the microwave oven.

- An eyedropper pipette for transferring the hot distilled water from the mug into the container with the gum arabic powder.

- A 1 mL syringe (without the needle) to measure out and dispense the benzyl alcohol preservative.

- A blue or amber glass jar to pour your ink into, the color of the vial will shield the ink from light, as phycocyanin is somewhat light-sensitive.

Reagents:

- 1.40 g of gum arabic powder (a binder that will help the ink adhere to many surfaces, it is used at around 5% concentration by weight (wt/wt) in the final mixture)

- 22.00 g of distilled or deionized water (solvent, the ink is water-based and using distilled or deionized water will help prolong the ink’s shelf-life)

- 0.28 mL of benzyl alcohol (preservative, mould inhibitor used at around 1 % wt/wt concentration in the final mixture)

- 0.28 g of sodium ascorbate (sodium salt of vitamin C, used as an antioxidant at a concentration of around 1% wt/wt to stabilize the phycocyanin blue pigment towards light and oxidation)

- 4.00 g of phycocyanin powder (blue pigment used in the ink)

- 1 drop of polysorbate 80 (optional, also known as Tween 80, used as a emulsifier to improve the flow properties of the ink)

Weigh out 1.40 g of gum arabic and transfer it to your small plastic container.

Add 22.00 g of hot distilled water (which you heated to a boil in the mug in the microwave oven) to the gum arabic, using the eyedropper pipette.

Dissolve the gum arabic by stirring with the handle of a spoon for a few minutes. The second photo shows what the gum arabic solution should look like. It is slightly cloudy and milky in appearance.

Draw 0.28 mL of benzyl alcohol with the syringe, then add it to the gum arabic solution and stir well.

Weigh out 0.28 g of sodium ascorbate, then add it to the mixture and stir well.

Weigh out 4.00 g of phycocyanin and add it to the mortar.

Once the gum arabic mixture has cooled down to room temperature, add it to the mortar containing the phycocyanin. It needs to be cooled down as the phycocyanin pigment is temperature sensitive, being a protein.

Thoroughly incorporate the phycocyanin powder into the liquid. If needed, use a spoon to scrape the blue powder from the pestle back into the mortar.

(Optional) - Add a drop of polysorbate 80 to the mixture and stir well.

Pour your ink into your blue or amber glass container and you're done!