29:null 2a:["$","title",null,{"children":"Ametameric (2025 version) | Job van der Zwan | Observable"}] 2f:T574,A terminal palette by [Øyvind Kolås](https://pippin.gimp.org/). **https://ctx.graphics/terminal/ametameric/**: > *1 in 22 humans have problems discriminating color due to deficient color vision, this is a computational design project, using stochastic gradient design and human steering to make palettes that work well for trichromats while having improved color contrast for all types of dichromats as well as maintaining contrast upon grayscale conversion.* > > *The main goal is a decent default terminal palette, the current local optimum in december 2025 is seen on the right; it is a big improvement on my first go at ametameric terminal palette in 2020.* > > **https://pippin.gimp.org/**: > *"a Repository/portfolio/gallery/documentation of digital creations and other artifacts by Øyvind Kolås, tools for experimental media creation, modification, curation and transformation."* As someone with protanomally I can confirm that it works better than the default palette for me. Given that a lot of terminal scripts assume the default palette when using colors for highlighting, using a radically different (prettier) palette often results in unreadable highlighted text. So this is a fine compromise for me. I'm curious how well it might work as a categorical color map, although finding a "best" order is tricky. Below I use OkLab to convert each color to a perceived brightness30:T7d0,function rgbaToOklab(rgba) { const { cbrt } = Math; const lab = [] for (let i = 0; i < rgba.length; i += 4) { const r = rgba[i]; const g = rgba[i + 1]; const b = rgba[i + 2]; // sRGB to linear sRGB - https://observablehq.com/@mbostock/lab-and-rgb#rgb_lrgb1 // assuming normalized c input, linear output cl is: // const cl = c <= 0.04045 ? c / 12.92 : ((c + 0.055) / 1.055) ** 2.4; // multiplying the constants by 255 to avoid wasteful conversions // 0.04045 * 255 == 10.31475 // 12.92 * 255 == 3294.6 // 0.055 * 255 == 14.025 // 1.055 * 255 == 269.025 const rl = r <= 10 ? r / 3294.6 : ((r + 14.025) / 269.025) ** 2.4; const gl = g <= 10 ? g / 3294.6 : ((g + 14.025) / 269.025) ** 2.4; const bl = b <= 10 ? b / 3294.6 : ((b + 14.025) / 269.025) ** 2.4; const l = 0.4122214708 * rl + 0.5363325363 * gl + 0.0514459929 * bl; const m = 0.2119034982 * rl + 0.6806995451 * gl + 0.1073969566 * bl; const s = 0.0883024619 * rl + 0.2817188376 * gl + 0.6299787005 * bl; const l_ = cbrt(l); const m_ = cbrt(m); const s_ = cbrt(s); const L = 0.2104542553 * l_ + 0.7936177850 * m_ - 0.0040720468 * s_; const A = 1.9779984951 * l_ - 2.4285922050 * m_ + 0.4505937099 * s_; const B = 0.0259040371 * l_ + 0.7827717662 * m_ - 0.8086757660 * s_; lab.push([L, A, B, i/4]); } return lab; } const ametameric2025_Oklab = rgbaToOklab(ametameric2025_u8) const ametameric2025_lightness_str = []; for (const [L] of ametameric2025_Oklab) { const str = (L*256|0).toString(16).toUpperCase().padStart(2, "0"); ametameric2025_lightness_str.push(`#${str}${str}${str}`); } const am2025sorted_okLab = ametameric2025_Oklab.slice().sort((a, b) => a[0] - b[0]); const am2025sorted_str = []; for (const [L] of am2025sorted_okLab) { const str = (L*256|0).toString(16).toUpperCase().padStart(2, "0"); am2025sorted_str.push(`#${str}${str}${str}`); } const am2025sorted = am2025sorted_okLab.map(v => ametameric2025[v[3]]) 31:[] 2d:{"id":"2d7ca9ae8715278c","slug":null,"title":"Ametameric (2025 version)","thumbnail":"69670c3466a9d8bfc545887b6a3ac293f41e52a6fd5db3be98c7b84a46acd299","access_level":"public","create_time":"$D2026-01-26T13:02:24.091Z","update_time":"$D2026-08-25T14:18:28.936Z","view_time":null,"first_public_time":"$D2026-01-26T14:08:15.625Z","fork":false,"stars":0,"starred":false,"owner":{"type":"team","id":"3f83172cfde1e56a","login":"jobleonard","name":"Job van der Zwan","avatar_url":"https://avatars-next.observableusercontent.com/808373580aa09723ceabb9cb31d01ea6db287280b59eaa63618e259f5d28dd71","tier":"starter_2024"},"version":398,"publish_version":null,"role":null,"authored":false,"authors":[{"type":"individual","id":"d36034ddfb454bdd","login":"jobleonard","name":"Job van der Zwan","avatar_url":"https://avatars-next.observableusercontent.com/808373580aa09723ceabb9cb31d01ea6db287280b59eaa63618e259f5d28dd71","tier":null}],"members":[{"type":"team","id":"3f83172cfde1e56a","login":"jobleonard","name":"Job van der Zwan","avatar_url":"https://avatars-next.observableusercontent.com/808373580aa09723ceabb9cb31d01ea6db287280b59eaa63618e259f5d28dd71","tier":"starter_2024","role":"editor"},{"type":"individual","id":"d36034ddfb454bdd","login":"jobleonard","name":"Job van der Zwan","avatar_url":"https://avatars-next.observableusercontent.com/808373580aa09723ceabb9cb31d01ea6db287280b59eaa63618e259f5d28dd71","tier":null,"role":"editor"}],"comments":[],"custom_thumbnail":true,"trashed":false,"subscribed":null,"forks":0,"collection":null,"type":"notebook","body":{"title":"Ametameric (2025 version)","cells":[{"id":67,"value":"# Ametameric (2025 version)","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined"},{"id":19,"value":"{\n const ctx = DOM.context2d(1020, 680);\n ctx.fillStyle = \"#CCC\";\n ctx.fillRect(0, 0, 1020, 680);\n ctx.font = \"bold 32px 'Melvian Code', monospace\";\n for (let i = 0; i < 2; i++) {\n for (let j = 0; j < 2; j++) {\n for (let k = 0; k < 4; k++) {\n const idx = i*4 + j*8 + k;\n ctx.fillStyle = ametameric2025[idx];\n const x = k * 150 + 210;\n const y = j * 150 + i * 300 + 40;\n console.log(ametameric2025[i], x ,y)\n ctx.fillRect(x, y, 150, 150)\n ctx.fillStyle = (idx & 0b10) ? \"#000\" : \"#FFF\"\n ctx.fillText(ametameric2025[idx].substring(1), x + 10, y + 130)\n }\n }\n }\n return ctx.canvas;\n}","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":0,"value":"$2f","pinned":false,"hidden":false,"mode":"md","author":"$undefined","summary":"$undefined"},{"id":194,"value":"function drawPalette(paletteIndices, showText){\n const w = 14*80;\n const h = 160;\n const ctx = DOM.context2d(w, h);\n ctx.fillStyle = \"#CCC\";\n ctx.fillRect(0, 0, w, h);\n ctx.font = \"14px 'Melvian Code', monospace\";\n const colorIndices = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 0, 15];\n const outlined = showText ? (str, x, y) => {\n ctx.fillStyle = \"#000\";\n ctx.fillText(str, x + 1, y);\n ctx.fillText(str, x + 1, y + 1);\n ctx.fillText(str, x, y +1);\n ctx.fillStyle = \"#FFF\";\n ctx.fillText(str, x, y);\n } : () => {};\n for (let i = 0; i < paletteIndices.length; i++) {\n const j = paletteIndices[i];\n const k = colorIndices[j];\n // am2025sorted\n ctx.fillStyle = ametameric2025[k];\n ctx.fillRect(i*80, 0, 80, 80);\n outlined(ametameric2025[k], i*80 + 5, 70);\n ctx.fillStyle = ametameric2025_lightness_str[k];\n ctx.fillRect(i*80, 80, 80, 80);\n outlined(j.toString(), i*80 + 5, 150);\n }\n return ctx.canvas;\n return ctx.canvas;\n}","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined"},{"id":220,"value":"drawPalette([0, 1, 2, 3, 4, 5, 6, 7, 8 ,9, 10, 11, 12, 13])","pinned":false,"hidden":false,"mode":"ts","author":"$undefined","summary":"$undefined"},{"id":224,"value":"function drawPaletteSorted(paletteIndices, showText){\n const w = 14*80;\n const h = 160;\n const ctx = DOM.context2d(w, h);\n ctx.fillStyle = \"#CCC\";\n ctx.fillRect(0, 0, w, h);\n ctx.font = \"14px 'Melvian Code', monospace\";\n const colorIndices = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 0, 15];\n const outlined = showText ? (str, x, y) => {\n ctx.fillStyle = \"#000\";\n ctx.fillText(str, x + 1, y);\n ctx.fillText(str, x + 1, y + 1);\n ctx.fillText(str, x, y +1);\n ctx.fillStyle = \"#FFF\";\n ctx.fillText(str, x, y);\n } : () => {};\n for (let i = 0; i < paletteIndices.length; i++) {\n const j = paletteIndices[i];\n const k = colorIndices[j];\n ctx.fillStyle = am2025sorted[k];\n ctx.fillRect(i*80, 0, 80, 80);\n outlined(am2025sorted[k], i*80 + 5, 70);\n ctx.fillStyle = am2025sorted_str[k];\n ctx.fillRect(i*80, 80, 80, 80);\n outlined(j.toString(), i*80 + 5, 150);\n }\n return ctx.canvas;\n return ctx.canvas;\n}","pinned":false,"hidden":false,"mode":"ts","author":"$undefined","summary":"$undefined"},{"id":221,"value":"drawPaletteSorted([\n 8, 4, 12, 2, 10, 6, 14, 1, 9, 5, 13, 3, 11, 7\n].map(v => v-1))","pinned":true,"hidden":false,"mode":"ts","author":"$undefined","summary":"$undefined"},{"id":6,"value":"const ametameric2025 = [\n \"#000000\", // black\n \"#850B10\", // red\n \"#548763\", // green\n \"#E18B00\", // brown\n \"#3D169E\", // blue\n \"#631D69\", // magenta\n \"#138FDF\", // cyan\n \"#C5C5C5\", // bright gray\n \"#4F4F4F\", // gray\n \"#C83B00\", // bright red\n \"#74C681\", // brigth green\n \"#FFC50B\", // yellow\n \"#0011FF\", // bright blue\n \"#B41DFF\", // bright magenta\n \"#1CD6FF\", // bright cyan\n \"#FFFFFF\" // white\n]","pinned":true,"hidden":false,"mode":"ts","author":"$undefined","summary":"$undefined"},{"id":16,"value":"const ametameric2025_u8 = Uint8Array.from([\n 0x00, 0x00, 0x00, 0xFF, // black\n 0x85, 0x0b, 0x10, 0xFF, // red\n 0x54, 0x87, 0x63, 0xFF, // green\n 0xe1, 0x8b, 0x00, 0xFF, // brown\n 0x3d, 0x16, 0x9e, 0xFF, // blue\n 0x63, 0x1d, 0x69, 0xFF, // magenta\n 0x13, 0x8f, 0xdf, 0xFF, // cyan\n 0xc5, 0xc5, 0xc5, 0xFF, // bright gray\n 0x4f, 0x4f, 0x4f, 0xFF, // gray\n 0xc8, 0x3b, 0x00, 0xFF, // bright red\n 0x74, 0xc6, 0x81, 0xFF, // bright green\n 0xff, 0xc5, 0x0b, 0xFF, // yellow\n 0x00, 0x11, 0xff, 0xFF, // bright blue\n 0xb4, 0x1d, 0xff, 0xFF, // bright magenta\n 0x1c, 0xd6, 0xff, 0xFF, // bright cyan\n 0xff, 0xff, 0xff, 0xFF, // white\n])","pinned":true,"hidden":false,"mode":"ts","author":"$undefined","summary":"$undefined"},{"id":131,"value":"$30","pinned":true,"hidden":false,"mode":"ts","author":"$undefined","summary":"$undefined"},{"id":225,"value":"am2025sorted_okLab","pinned":true,"hidden":false,"mode":"ts","author":"$undefined","summary":"$undefined"},{"id":223,"value":"[0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15].map(v => reverseNbits(v, 4))","pinned":true,"hidden":false,"mode":"ts","author":"$undefined","summary":"$undefined"},{"id":222,"value":"function reverseNbits(v, n) {\n switch(n) {\n case 32:\n v = (v >>> 16) + (v << 16);\n case 16:\n v = ((v & 0xFF00FF00) >>> 8) + ((v & 0xFF00FF) << 8);\n case 8:\n v = ((v & 0xF0F0F0F0) >>> 4) + ((v & 0xF0F0F0F) << 4);\n case 4:\n v = ((v & 0b11001100110011001100110011001100) >>> 2) + ((v & 0b110011001100110011001100110011) << 2);\n case 2:\n v = ((v & 0b10101010101010101010101010101010) >>> 1) + ((v & 0b1010101010101010101010101010101) << 1);\n return v;\n default: {\n let rv = 0;\n for (let i = 0; i < n; i++) {\n rv += rv + ((v >>> i)&1);\n }\n return rv;\n }\n }\n}","pinned":true,"hidden":false,"mode":"ts","author":"$undefined","summary":"$undefined"}],"files":"$W31","stdlib":"1","titling":"auto"}} 2e:"$2d:body"