Ink Review: Robert Oster Aqua

Set sail with the new inks from Robert Oster out of Australia. I scoured the DC Pen Show in search of someone who had them in stock as I knew they were on their way to the US shores but the only vendor who had any in stock yet was Federalist Pens and Paper. I got a bottle of Aqua which ended up being the absolute right choice for my first bottle of Robert Oster Signature Fountain Pen ink because it is gorgeous!

In the past, I suggested that KWZ Menthol Green might good a good alternative to J. Herbin Emerald of Chivor if you’re looking for that deep teal green but would rather skip the pen-clogging sparkles. I hereby amend my recommendation to Robert Oster Aqua which is a perfct color match to J. Herbin Emerald of Chivor sans sparkles. Seriously.

Add to that the exquisite red halo and lovely shading and you have an exceptionally fabulous ink.

Other folks have suggested that some Oster were dry. I was using this in my Lamy Scala with EF 14K nib and had no issues with hard starts or skipping and Lamy nibs tend to be a little dry so I didn’t notice any issues. If anything, I found the flow on this ink particularly good.

This is my first Oster ink, and it certainly won’t be my last, so I’ll let you know if I find any of the other inks dry. The Aqua seems quite smooth and has been in my Lamy for several weeks with no issues. It’s even flown back from DC and on to SF and back without any problems.

Overall, I really like this ink. It might usurp Ku-Jaku as one of my favorite teal inks once I’ve seen how it performs in a few more pens but so far I’m most impressed with it.

oster aqua ink color comparison 2

UPDATE: Erik and Bradley both mentioned in the comments some color comparisons that I neglected to include so, for their benefit, I’ve added them above. Diamine Teal is darker and greener. It actually looks brighter in my photo than in real life. The Oster Aqua is much more vivid. and the red sheen and shading is far more apparent. The Edelstein Aquamarine is a pretty color but its lighter overall. There is a bit of a halo at the edges but not nearly as pronounced as the Oster Aqua which is almost metallic and again more vivid and saturated overall. There is a more faded denim quality to the Edelstein Aquamarine, a little more subdued. And the Diamine Teal is downright reserved in comparison. I hope that helps!


This ink was purchased from Federalist Pens and Paper at the DC Pen Show. It can be purchased online through their web site for $18 per bottle plus shipping.

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11 comments / Add your comment below

    1. I added a photo with the swatch of Aqua and Diamine Teal to the review. The Teal is much darker and more subdued. The Aqua is so saturated and vivid!

  1. This looks like it might go quite well with the new Pelikan Aquamarine! I picked up Bondi Blue and Jade at the SF Pen Show and love them both. Thanks for the review!

    1. I added a photo with a sample of Edelstein Aquamarine for comparison purposes. I hope that will give you a visual guide. They are definitely in the same family.

  2. Oooo… This one looks interesting! What is the volume of the bottle?

    I’m in Indonesia, so it would be crazy to buy an ink made by our neighbors in Australia from a reseller in the U.S.A. But I don’t see an alternative 🙁

    Robertoster(dot)com(dot)au is just a veil page pushing you on to social media, so nothing worthwhile there. Sigh…

    1. David, I’ll check and see if there are any resellers in Australia, Indonesia or other Asian countries that would make shipping more convenient for you.

      As for the volume in the bottles, its 50ml per bottle.

    2. David, pensivepens is the Aussie reseller, otherwise try contacting Robert directly over social media. He’s super friendly and might be able to point you to a more local reseller or maybe even direct. He used to have an ebay store too (osteralia).
      There are both 50ml and 100ml bottles.

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