Diamine Ink vs Pilot Iroshizuku Ink: Which Fountain Pen Ink Brand Is Better?

Diamine and Pilot Iroshizuku are two of the most popular fountain pen ink brands in the world. Both offer exceptional writing performance, beautiful colors, and loyal followings among fountain pen enthusiasts. However, they approach fountain pen ink from very different perspectives. Diamine is known for its massive color selection, affordability, and versatility, while Pilot Iroshizuku is celebrated for its premium formulations, smooth writing characteristics, and elegant Japanese-inspired colors.

If you're trying to decide between Diamine and Pilot Iroshizuku fountain pen inks, this guide compares their flow, color selection, shading, sheen, dry times, value, and overall writing experience.

Diamine vs Pilot Iroshizuku at a Glance

Diamine Fountain Pen Ink Overview

Diamine ink company has been producing fountain pen inks since 1864 and is one of the oldest ink manufacturers still operating today. The company offers hundreds of colors and has become a favorite among both beginners and experienced fountain pen users.

Popular Diamine collections include:

• Diamine Standard Inks


• Diamine Inkvent Series


• Diamine Shimmer Inks


• Diamine 150th Anniversary Collection


• Diamine Forever Ink Series

Diamine is frequently recommended in our guide to Top Fountain Pen Ink Brands. Explore all the fountain pen inks from Diamine.

Pilot Iroshizuku Fountain Pen Ink Overview

Pilot Iroshizuku inks were inspired by Japanese landscapes, flowers, and natural elements. Since their introduction, they have become some of the most respected premium fountain pen inks available.

Popular Pilot Iroshizuku inks include:

• Kon-Peki


• Shin-Kai


• Tsuki-Yo


• Yama-Budo


• Take-Sumi


• Asa-Gao

Iroshizuku inks are often considered the benchmark for premium everyday fountain pen inks because of their exceptional flow and reliability. Shop all of our Pilot fountain pen inks.

Flow and Writing Performance

One of the biggest differences between these brands is how they feel while writing.

Pilot Iroshizuku inks are known for being exceptionally smooth and lubricated. Many users notice that a pen feels smoother and wetter when filled with Iroshizuku ink.

Diamine inks vary more by color but generally provide reliable, consistent performance across a huge range of formulations.

Learn more about ink flow in our guide to Difference with Wet vs Dry Fountain Pen Inks.

Color Selection

This is one area where Diamine has a significant advantage.

Diamine offers one of the largest fountain pen ink catalogs available, with hundreds of colors covering every shade imaginable.

Pilot Iroshizuku takes a different approach. Rather than offering hundreds of colors, Pilot focuses on a carefully curated collection of premium inks designed for consistent performance and broad appeal.

For inspiration, see our guides to Best Colors for Fountain Pen Inks and Guide to Fountain Pen Ink Colors.

Shading and Sheen

Both brands produce excellent shading inks, although their styles differ.

Diamine offers numerous highly sheening inks and dramatic shading inks, particularly within the Inkvent collection.

Iroshizuku inks typically produce elegant, refined shading that enhances everyday writing without overwhelming it.

Related resources:

• What Is Fountain Pen Ink Shading?


• What Is Fountain Pen Ink Sheening?

Dry Time Comparison

Because Iroshizuku inks tend to flow wetter, they may take slightly longer to dry than some Diamine inks.

Actual dry times depend heavily on the specific ink color, nib size, and paper being used.

For more information, see our Guide to Fountain Pen Ink Drying Times.

Water Resistance

Neither standard Diamine inks nor standard Pilot Iroshizuku inks are designed primarily as waterproof document inks.

If permanence is important, consider pigment-based or permanent fountain pen inks instead.

Related guides:

• Dye vs Pigment Fountain Pen Ink


• Best Permanent Fountain Pen Inks


• Top Archival Fountain Pen Inks

Best Diamine Inks

• Diamine Oxford Blue


• Diamine Writer's Blood


• Diamine Earl Grey


• Diamine Oxblood


• Diamine Aurora Borealis

Best Pilot Iroshizuku Inks

• Pilot Iroshizuku Kon-Peki


• Pilot Iroshizuku Shin-Kai


• Pilot Iroshizuku Tsuki-Yo


• Pilot Iroshizuku Yama-Budo


• Pilot Iroshizuku Take-Sumi

Value Comparison

Diamine is widely regarded as one of the best values in fountain pen ink. It provides excellent performance at an affordable price and offers more colors than almost any other manufacturer.

Pilot Iroshizuku inks command a premium price, but many users feel the superior flow, lubrication, and writing experience justify the additional cost.

Who Should Buy Diamine Ink?

• Writers who want the largest color selection


• Students and everyday writers


• Users seeking excellent value


• Ink collectors


• Writers who enjoy experimenting with colors

Who Should Buy Pilot Iroshizuku Ink?

• Professionals


• Daily writers


• Users seeking maximum smoothness


• Writers who value premium ink performance


• People looking for dependable everyday inks

Final Verdict: Diamine vs Pilot Iroshizuku

Both brands are among the best fountain pen inks available today.

• Choose Diamine if you want exceptional value, a massive color selection, and excellent overall performance.


• Choose Pilot Iroshizuku if you prioritize smooth writing, outstanding lubrication, and premium everyday performance.

Many fountain pen enthusiasts use both brands, choosing Diamine for variety and Iroshizuku for pure writing enjoyment.

Related Fountain Pen Ink Guides

• Sailor Fountain Pen Ink vs Pilot Iroshizuku Ink


• Top Fountain Pen Ink Brands


• Wet vs Dry Fountain Pen Inks


• Dye vs Pigment Fountain Pen Ink


• Top Colors for Inks for Fountain Pens


• Fountain Pen Ink Color Guide

Frequently Asked Questions