on saleRobert Oster Deep Sea - Ink Sample

Product Code IS-RO-50266

In Stock

out of stock

on saleRobert Oster Deep Sea - Ink Sample

Product Code IS-RO-50266

In Stock

out of stock


A 2ml sample of Robert Oster Deep Sea fountain pen ink, in a labeled plastic vial.

Robert Oster
Ink Samples
Fast Drying

Whether or not the ink contains glittery particles.

Freeze Resistant

Whether or not an ink is specially formulated to better withstand freezing temperatures.

Iron Gall

Ink made from iron salts and tannic acids. Though quite permanent and waterproof, these inks are typically known for causing chemical corrosion to metal pen parts (especially the nib) and should be used sparingly or with less-valuable pens.


Whether or not an ink is specially formulated to increase flow in your pen.


Whether or not the ink contains finely-ground solid particles in liquid suspension.

Water Resistant

Whether or not the ink, once dried on the paper, will resist being washed away with water.


Customer Reviews

Based on 5 reviews
Mike S.J.
Robert Oster Deep Sea

Instant favorite. Robert Oster inks do not disappoint. Nice and wet, good shading.

Jenny K.
Absolutely stunning!

I have found the perfect match to my teal-colored Lamy Safari. The shading is beautiful. Will definitely get a bottle of this one.

Great gift

I am introducing fountain pens to my daughter in love and she love this color. I couldn't get a better gift.

Grat color, but doesnt match the name

While this is a very nice color. I feel the name is wrong. When I think of Deep Sea I think of a deep blue geen. In my world, Tranquility and Deep Sea would switch. Ive tried it in a couple different pens, including stubs and it doesn't get much darker than what you see here. Although, you do get nore shading with a stub.

Beautiful dark teal ink

I sampled this ink along with Tranquility and Fire & Ice as soon as Goulet stocked them. I was initially disappointed with Deep Sea. I'd put it in a Lamy sp. ed. Dark Lilac with a medium nib and the ink came out very very flat and dull. I'd ben having issues with flow in that pen and just did a clean out, hoping that what should be a wet, highly saturated ink would solve the issue (I was wrong). I decided to give Deep Sea another shot in a TWSBI Fine-nibbed Eco and wow, what a difference! Deep Sea is an amazing dark teal with a red sheen that looks lovely on both L1917 and Tomoe River paper. This is a wet ink with a slightly longer dry time than I prefer and I have not seen any bleed-through. Tranquility, by comparison, shows as a bright turquoise, though the two can appear similar when ink is really gushing (like right after a fill). Despite both being on the green side of teal/turquoise, these are two very different colors and I love them both. Just make sure you put them in the right pen!

FAQ about Ink Samples

How do I fill my fountain pen from an ink sample vial? 8EDA1617-F73A-4DAF-8245-6D2BF4ABEB7B

It depends on the fountain pen's filling mechanism.

Check out our blog post on How to Fill a Fountain Pen from an Ink Sample Vial.

How much writing can I do with 2ml of ink? 8EDA1617-F73A-4DAF-8245-6D2BF4ABEB7B

It really depends on how big or small you write, and the nib size you’re using. We find that usually you can get 2 good fills for a typical converter with our Ink samples, or one good fill with a piston-filling pen. How much writing depends on you more than anything else, so we recommend experimenting with different nib sizes to find what works best for you. 

What is shading, sheening, or shimmering ink? 8EDA1617-F73A-4DAF-8245-6D2BF4ABEB7B

Shading - A common (and often desired) result of a fountain pen ink pooling in certain parts of a letter when writing, so that the color and saturation of the ink appears different within a single letter or word. This characteristic cannot be achieved with ballpoint or rollerball pens and is a very appealing aspect of fountain pen use for those particularly drawn to all the pretty ink colors.

Sheen - Characteristic of a fountain pen ink where when ink pools another color can be seen on top of the ink, especially when looked at in different light angles using certain paper types. There is no way to guarantee an ink will sheen, but using a larger nib on a pen will help obtain sheening results in your writing.

Shimmering - Fountain pen ink that has small particles of glitter mixed in.

Is shimmering ink safe to use in fountain pens? 8EDA1617-F73A-4DAF-8245-6D2BF4ABEB7B

Yes! Shimmering ink is a great way to add some flare to your writing. We have found that a larger nib will showcase more shimmering particles while writing, but you can use any nib size and shimmering ink. All the ink we sell is safe for use in fountain pens.

You can learn more in our blog: How to Write with Shimmering Ink.

What's your return policy for ink samples? 8EDA1617-F73A-4DAF-8245-6D2BF4ABEB7B

We do not accept returns for ink that has been used. Otherwise, we accept returns on unused ink products for up to 30 days from purchase. You can read all our Return Policies here.

To initiate a return, please submit a request at the Return Portal. Our Customer Care team might reach out to you for more information.