Introduction

In Digital Humanities research, comparing and examining multiple materials side by side is a common practice. A high-performance image viewer is essential for tasks such as comparing different manuscripts or examining artworks before and after restoration.

This article introduces Mirador, a IIIF-compatible image viewer jointly developed by Stanford University and Harvard University.

What is Mirador?

Mirador is a web-based image viewer compatible with IIIF (International Image Interoperability Framework). Its most distinctive feature is its multi-window interface, which allows users to open multiple windows simultaneously to compare images.

Published under the Apache 2.0 License, it is widely used around the world, particularly in academic institutions. The current version, Mirador 3, is built on a modern architecture based on React.

Key Features

Multi-Window Comparison

Mirador’s core functionality — multi-window display — enables simultaneous side-by-side comparison of images from multiple IIIF manifests. Windows can be freely resized and arranged, functioning as a researcher’s workspace.

Annotation Support

Mirador supports the IIIF annotation specification, allowing users to add annotations directly to images. Research notes and tags can be associated directly with images, making it suitable for collaborative research.

Plugin Ecosystem

Mirador 3 adopts a plugin architecture that allows functionality to be extended. Notable plugins include:

  • mirador-image-tools — brightness/contrast adjustment, inversion, grayscale conversion
  • mirador-annotations — annotation creation and editing
  • mirador-dl — image downloading
  • mirador-share — sharing link generation

Layer Display

Mirador supports overlaying multiple layers, enabling uses such as superimposing transcribed text over original images or toggling between images captured at different wavelengths.

Drag and Drop

IIIF manifest URLs can be added to the viewer via drag and drop, making it easy to gather materials from collections at different institutions and compare them in a single workspace.

Getting Started

Mirador is available as an npm package.

npm install mirador

To embed it in a React application:

import Mirador from 'mirador';

const config = {
  id: 'mirador-viewer',
  windows: [{
    manifestId: 'https://example.org/manifest.json'
  }]
};

Mirador.viewer(config);

Use Cases in DH

Manuscript Comparison

Different manuscripts of the same text can be displayed side by side to compare textual variations and layout differences. This is effective for medieval European manuscript studies and Japanese classical text research.

Art Analysis

Artworks can be zoomed at high resolution to analyze brushwork and pigment usage. Using image processing plugins, brightness and contrast can be adjusted to reveal details not visible to the naked eye.

Cross-Collection Comparison

Leveraging IIIF interoperability, materials from different institutions’ collections can be brought together for comparison. For example, different editions of the same work held by the National Diet Library and the British Library can be displayed side by side for research.

Educational Use

When presenting materials in courses, Mirador’s multi-window functionality enables effective display of multiple resources. Having students use the annotation feature can also promote active learning.

Comparison with Universal Viewer

Mirador specializes in comparative image analysis, excelling in multi-window display, annotations, and extensibility through plugins. Universal Viewer, on the other hand, supports media types beyond images, including audio, video, and 3D models.

The general approach is to choose Mirador for research-oriented image comparison and Universal Viewer for publishing multimedia content.

Conclusion

Mirador is the optimal open-source viewer for IIIF image comparison and analysis. With parallel comparison through multi-window display, annotation capabilities, and a rich plugin ecosystem, it serves as a powerful tool for DH researchers. Freely available under the Apache 2.0 License, it features a modern React-based architecture with excellent extensibility.