Ink Review - Robert Oster Signature -  Verde de Rio

Robert Oster Signature Verde de Rio (River Green) ink is a slightly unusual shade of mid green to olive ink that leans more yellow than blue. It’s a darker meadow green shade without being a bright green. Very attractive. Many inks in this colour range are darker and “muddier” than Verde de Rio.

Verde de Rio flowed well through my pens, without feeling dry, and lubrication felt nicely smooth when writing across the page. I saw some lovely shading but failed to spot any sheen.

I didn’t notice any skips or hard starts when I put the uncapped pen down to do swab tests, dry times and water resistance. Nor did I see any spread or feathering on the papers I wrote on.

I like green inks in this colour range and this is well behaved. I would consider buying a bottle of this one. It’s now on my list. 

Robert Oster inks come in 50ml plastic bottles that are quite tall making it easy to fill fountain pens from, but for me they are quite easy to tip over so I usually place mine in a wide, squat, glass pot when I open it. They have good identification labels on the tops of the bottles making it easy to pick out the one you want when they are grouped together.


  • Start-up: Immediate.
  • Nib Dry-out: Not noticed.
  • Nib Creep / “Crud”: Not seen.
  • Show through/ Bleed through: Showed through slightly on some papers but I could still write on the reverse.
  • Staining (pen): Not seen after several days - easy clean-up.
  • Staining (hands): My hands were clean after one wash
  • Clogging: Not seen.
  • Water resistance: Not sold as waterproof and water resistance is low

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