on saleRobert Oster Motor Oil - 50ml Bottled Ink

Product Code RO-50225

In Stock

out of stock

on saleRobert Oster Motor Oil - 50ml Bottled Ink

Product Code RO-50225

In Stock

out of stock

50ml Bottle

50ml plastic bottle of Robert Oster Signature fountain pen ink in the color Motor Oil.

Robert Oster Signature Inks are handmade in Australia. The recyclable PET bottles are manufactured in Australia's first carbon neutral plastics plant.

Note: Robert Oster is in the process of changing the labels on their bottle and the label on the bottle you receive may vary from what is pictured here.

A message from Robert Oster:

My great interest in fountain pen inks – and by extension inks that combine many creative applications – began with the birth of my love of fountain pens in 1989.

As Robert Oster Signature Inks are quite recent to the market, think of the interim between 1989 and today, as the fertile ground into which my present love of all things ink was seeded and grown.

The contents and packaging of my Inks are all nature friendly and the colours a genuine inventory of the Australian palette.

Robert Oster Signature originates from one of the most famous wine producing regions of the world, the Coonawarra district of South Australia, an idyllic setting with great influence on the senses. There is my inspiration. It’s a joy to share it with you.

Robert Oster
Bottled Ink
Bottle Material
Bottle Opening Diameter
17.4mm (0.69in)
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 8 reviews
Noel L.
Oster, so good!

My first ink from Robert Oster. A slightly olive-y brown that writes very smoothly from my Pilot Decimo M on Clairefontaine paper. Subtle shading, perfect flow, no feathering, dries pretty quickly. Very, very pleased.

Low profile ink

This ink doesn't call attention to it's self. It's a soothing ink that you can use without being splashy. It's introverted ink.You could probably get away with using this in an office that requires black ink, but it isn't black. Not black, not grey, not brown, not green, definitely not blue... It just is what it is without any fanfare. I think I will use it for journaling.


The color is interesting, almost unplaceable. Sludgy brown or black or even grey in shade/low light, but with tones of dirty bamboo green (the trunk of the plant not the leaves) in bright light/close inspection. Motor oil is an apt name. It's a very interesting but sober and serious color. Moody, in a nice way, yet suitable for all audiences. Under appreciated and under reviewed on the web, I feel. Re. some other reviews complaining about hard starts and clogging, they may have a point, but it does not seem too serious and it may depend on the pen. My experience so far is with a (an otherwise perfect) sailor 1911L (M). Has not clogged at all, but had a hard start when writing fast once.

Nicole G.
New signature ink

One of the first samples I got and the first sample ink that I just had to get a bottle of - this is my usual daily use ink any time I don't need water resistance. This may become my 'signature' ink. The pictures below show it on River, Rhodia, and my offbrand mixed media journal, respectively.

Jeff L.
Love this color! Love the name!

I was looking for an ink that when dry resembled the oxidized iron ink they used to use that you see on old documents from history. It was dead on. The only reason I didn't give it 5 stars was because it was hard starting in my pen even with the cap off for only a short period of time. Made it difficult for completing or creating check lists quickly. But other than that it is great!

FAQs about Bottled Ink

Which pens can accept this ink? 8EDA1617-F73A-4DAF-8245-6D2BF4ABEB7B

Any of these fountain pens will work with bottled ink. Typically, as long as the pen can be filled with a converter, has a built-in filling mechanism like a piston, or can be eyedropper-filled, it can accept bottled ink.

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.

My ink smells funny, is it safe to use? 8EDA1617-F73A-4DAF-8245-6D2BF4ABEB7B

Generally yes! Ink does not smell good- it usually has a chemical smell, along with other scents such as sulfur, rubber, chemicals or even paint. However, as long as you’re not seeing anything floating in the ink, it should be safe to use.

It’s cold and my ink froze; is it safe to use? 8EDA1617-F73A-4DAF-8245-6D2BF4ABEB7B

Yes, frozen ink will not hurt your pen (after it’s thawed of course!) The issue with ink freezing is primarily a concern because certain glass bottles could break as the water-based ink expands, and then you’d have a mess!

What is your return policy for bottled ink? 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.