https://tech.ldas.jp/en/tags/presentation-api/Recent content in Presentation-Api on Digital Archive Systems Tech BlogHugoenWed, 29 Apr 2026 23:30:00 +0900https://tech.ldas.jp/en/posts/iiif-mirador-annotation-motivation-supplementing-commenting/Wed, 29 Apr 2026 23:30:00 +0900https://tech.ldas.jp/en/posts/iiif-mirador-annotation-motivation-supplementing-commenting/<blockquote> <p>This article is co-authored with generative AI. While I have cross-checked facts against official documentation where possible, errors may remain. Please verify primary sources before making important decisions.</p></blockquote> <h1 id="tldr">TL;DR</h1> <ul> <li>I shipped per-canvas OCR text as IIIF Presentation 3 annotations with <code>motivation: &quot;supplementing&quot;</code>. Annona and other spec-aware viewers rendered them. Mirador 4.0.0 (<code>projectmirador.org/embed</code>) showed nothing in the Annotations side panel.</li> <li>Root cause: in <strong>Mirador 4.0.0 release</strong>, <code>config.annotations.filteredMotivations</code> defaults to <code>['oa:commenting', 'oa:tagging', 'sc:painting', 'commenting', 'tagging']</code> — <strong><code>supplementing</code> is not in the allowlist</strong>, so an annotation whose only motivation is <code>supplementing</code> is filtered out of the side panel.</li> <li>Mirador <code>master</code> has since flipped the default to <code>filteredMotivations: []</code> (no filter), but at the time of writing no release ships that change. The released filter still applies in the wild.</li> <li>Putting <code>motivation</code> as <code>[&quot;commenting&quot;, &quot;supplementing&quot;]</code> lets the annotation through Mirador 4.0.0&rsquo;s filter via <code>commenting</code>, while keeping <code>supplementing</code> so spec-aware viewers / text-overlay plugins still recognise it as a transcription.</li> <li>IIIF Presentation 3 §3.5 &ldquo;Values for motivation&rdquo; only defines <code>painting</code> and <code>supplementing</code>; other motivation terms (<code>commenting</code>, <code>tagging</code>, …) come from the Web Annotation Data Model. The basis for allowing arrays is IIIF §4.3 (Properties with Multiple Values) plus Web Annotation §3.3.5.</li> <li>Don&rsquo;t add <code>painting</code> alongside. Each canvas already has a <code>painting</code> annotation for the image — adding another forces the viewer to pick which one &ldquo;fills&rdquo; the canvas, with implementation-dependent results.</li> </ul> <h1 id="what-happened">What happened</h1> <p>While extending the public API for the <a href="https://hiraga.ldas.jp/">Hiraga Yuzuru Digital Archive</a>, I added a per-canvas OCR-text endpoint that returns annotations as a Presentation 3 <code>AnnotationPage</code>, referenced from each canvas&rsquo;s <code>annotations[]</code>:</p>