India Ink - Uses Other Than Writing

Uses Other Than Writing

• Hanetsuki (羽根突き, 羽子突き) is a Japanese traditional game, similar to badminton, played by girls at the New Year with a rectangular wooden paddle called a hagoita and a brightly-colored shuttlecock. The shuttlecock must be kept in the air as long as possible. Girls who fail to hit the shuttlecock get marked on the face with India ink.
• Amateur tattoo artists will sometimes use India ink for tattooing the skin. Non-medical grade India ink should not be used for homemade tattoos because it contains chemicals which could cause poisoning.
• In pathology laboratories, India ink is applied to surgically removed tissue specimens to maintain orientation and indicate tumor resection margins. The painted tissue is sprayed with acetic acid, which acts as a mordant, "fixing" the ink so it doesn't track. This ink is used because it survives tissue processing, during which tissue samples are bathed in alcohol and xylene and then embedded in paraffin wax. When viewed under the microscope, the ink at the tissue edge informs the pathologist of the surgical resection margin or other point of interest.
• Microbiologists use India ink to stain a slide containing micro-organisms. The background is stained while the organisms remain clear. This is called a negative stain. India ink, along with other stains, can be used to determine if a cell has a gelatinous capsule. A common application of this procedure in the clinical microbiology laboratory is to confirm the morphology of the encapsulated yeast Cryptococcus spp. which cause cryptococcal meningitis.
• Model railroaders use a mixture of India ink and isopropyl alcohol as a wood stain, graying wood to appear aged and to bring out detail.
• India ink is used diluted as an ultra-fine polishing medium for making precise optical surfaces on metals.
• In ophthalmology, it was and still is used to some extent in corneal tattooing.
• Once dry, its conductive properties make it useful for electrical connections to difficult substrates, such as glass. Although relatively low in conductivity, surfaces can be made suitable for electroplating, low-frequency shielding, or for creating large conductive geometries for high voltage apparatuses. A piece of paper impregnated with India ink serves as a grid leak resistor in some tube radio circuits.
• Zoological museum specimens were often tagged in India ink, either directly or on a piece of tracing paper stored along the specimen, because of its durability even when submerged in preservative fluids.