Robert Oster School Blue Fountain Pen Ink — 50 mL

Robert Oster School Blue is a dark, practical blue with enough shading to keep it from becoming anonymous. In larger swabs and wetter lines it can lean slightly teal, while finer writing stays closer to a classic dark blue.

Independent testing shows visible shading, modest sheen under favorable conditions, average flow, and low water resistance. It dries at a moderate pace and remains easy to read across nib sizes, making it one of the more straightforward Robert Oster colors for daily use.

Ink character

• Color: dark blue with a slight teal cast in wetter areas
• Shading: medium
• Sheen: slight, paper-dependent
• Shimmer: none
• Flow: moderate
• Water resistance: low
• Best suited to: everyday notes, study, correspondence, office writing

School Blue does exactly what a good everyday blue should do, but with enough tonal movement to remind you that the line came from a fountain pen rather than a disposable ballpoint.