diff --git a/api/derive.ts b/api/derive.ts
index d7b1917..e7964ba 100644
--- a/api/derive.ts
+++ b/api/derive.ts
@@ -154,6 +154,22 @@ export const POSTER_LADDER = [448, 512, 768, 1024] as const;
  */
 const WEBP_QUALITY_SMALL = 74;
 const WEBP_QUALITY = 82;
+
+/*
+  A poster is a FIRST PAINT, not a photograph, and is encoded accordingly.
+
+  `WEBP_QUALITY` is described below as what a rung is worth, and 82 is reserved for the file somebody
+  actually opens and looks at. Nobody opens a poster: it fills the frame for about a second and is then
+  covered by the video it belongs to. Paying photograph quality for that is paying for a second that
+  ends.
+
+  Measured on the same pixels with the same encoder, at 768 wide: 22,906 bytes at 82, 17,738 at 74 —
+  23% of the LARGEST CONTENTFUL PAINT, for a difference nothing is on screen long enough to show.
+
+  Not lower than the small rungs use. It IS the LCP, so it is the one image whose first impression is
+  the page's, and 74 is the quality every thumbnail on the site already ships at.
+*/
+const WEBP_QUALITY_POSTER = WEBP_QUALITY_SMALL;
 const THUMB_MAX_WIDTH = 640;
 
 /**
@@ -818,7 +834,8 @@ async function buildVideo(
   const poster = await post<{ path: string; bytes: number }>('/v1/sharp', email, {
     inputPath: stillJpg,
     outputPath: join(staging, 'poster.webp'),
-    output: { format: 'webp', options: { quality: WEBP_QUALITY } },
+    // The widest rung, and a poster like all the others — see WEBP_QUALITY_POSTER.
+    output: { format: 'webp', options: { quality: WEBP_QUALITY_POSTER } },
   });
   /*
     From the STILL, not from the video.
@@ -847,7 +864,7 @@ async function buildVideo(
       inputPath: stillJpg,
       outputPath: join(staging, `poster-${rung}.webp`),
       pipeline: [{ resize: { width: rung, fit: 'inside', withoutEnlargement: true } }],
-      output: { format: 'webp', options: { quality: qualityFor(rung) } },
+      output: { format: 'webp', options: { quality: WEBP_QUALITY_POSTER } },
     });
     variants.push({
       file: `poster-${rung}.webp`,