[{"data":1,"prerenderedAt":52},["ShallowReactive",2],{"i-lucide:menu":3,"i-lucide:grip":8,"i-lucide:chevron-right":10,"i-lucide:moon":12,"i-lucide:sun":14,"i-material-symbols:language":16,"i-lucide:chevron-down":18,"i-lucide:shield-check":20,"i-lucide:mail":22,"i-tabler:markdown":24,"i-lucide:code-xml":26,"i-lucide:film":28,"i-lucide:file-text":30,"i-lucide:box":32,"i-lucide:code-2":34,"i-lucide:image":35,"i-lucide:square-sigma":37,"i-lucide:gamepad-2":39,"i-lucide:sparkles":41,"i-lucide:graduation-cap":43,"blog-body-compress-scanned-pdf-en":45,"i-lucide:lightbulb":46,"i-lucide:minimize-2":48,"i-lucide:image-down":50},{"left":4,"top":4,"width":5,"height":5,"rotate":4,"vFlip":6,"hFlip":6,"body":7},0,24,false,"\u003Cpath fill=\"none\" stroke=\"currentColor\" stroke-linecap=\"round\" stroke-linejoin=\"round\" stroke-width=\"2\" d=\"M4 5h16M4 12h16M4 19h16\"\u002F>",{"left":4,"top":4,"width":5,"height":5,"rotate":4,"vFlip":6,"hFlip":6,"body":9},"\u003Cg fill=\"none\" stroke=\"currentColor\" stroke-linecap=\"round\" stroke-linejoin=\"round\" stroke-width=\"2\">\u003Ccircle cx=\"12\" cy=\"5\" r=\"1\"\u002F>\u003Ccircle cx=\"19\" cy=\"5\" r=\"1\"\u002F>\u003Ccircle cx=\"5\" cy=\"5\" r=\"1\"\u002F>\u003Ccircle cx=\"12\" cy=\"12\" r=\"1\"\u002F>\u003Ccircle cx=\"19\" cy=\"12\" r=\"1\"\u002F>\u003Ccircle cx=\"5\" cy=\"12\" r=\"1\"\u002F>\u003Ccircle cx=\"12\" cy=\"19\" r=\"1\"\u002F>\u003Ccircle cx=\"19\" cy=\"19\" r=\"1\"\u002F>\u003Ccircle cx=\"5\" cy=\"19\" r=\"1\"\u002F>\u003C\u002Fg>",{"left":4,"top":4,"width":5,"height":5,"rotate":4,"vFlip":6,"hFlip":6,"body":11},"\u003Cpath fill=\"none\" stroke=\"currentColor\" stroke-linecap=\"round\" stroke-linejoin=\"round\" stroke-width=\"2\" d=\"m9 18l6-6l-6-6\"\u002F>",{"left":4,"top":4,"width":5,"height":5,"rotate":4,"vFlip":6,"hFlip":6,"body":13},"\u003Cpath fill=\"none\" stroke=\"currentColor\" stroke-linecap=\"round\" stroke-linejoin=\"round\" stroke-width=\"2\" d=\"M20.985 12.486a9 9 0 1 1-9.473-9.472c.405-.022.617.46.402.803a6 6 0 0 0 8.268 8.268c.344-.215.825-.004.803.401\"\u002F>",{"left":4,"top":4,"width":5,"height":5,"rotate":4,"vFlip":6,"hFlip":6,"body":15},"\u003Cg fill=\"none\" stroke=\"currentColor\" stroke-linecap=\"round\" stroke-linejoin=\"round\" stroke-width=\"2\">\u003Ccircle cx=\"12\" cy=\"12\" r=\"4\"\u002F>\u003Cpath d=\"M12 2v2m0 16v2M4.93 4.93l1.41 1.41m11.32 11.32l1.41 1.41M2 12h2m16 0h2M6.34 17.66l-1.41 1.41M19.07 4.93l-1.41 1.41\"\u002F>\u003C\u002Fg>",{"left":4,"top":4,"width":5,"height":5,"rotate":4,"vFlip":6,"hFlip":6,"body":17},"\u003Cpath fill=\"currentColor\" d=\"M8.125 21.213q-1.825-.788-3.187-2.15t-2.15-3.188T2 11.988t.788-3.875t2.15-3.175t3.187-2.15T12.013 2t3.875.788t3.175 2.15t2.15 3.175t.787 3.875t-.787 3.887t-2.15 3.188t-3.175 2.15t-3.875.787t-3.888-.787M12 19.95q.65-.9 1.125-1.875T13.9 16h-3.8q.3 1.1.775 2.075T12 19.95m-2.6-.4q-.45-.825-.787-1.713T8.05 16H5.1q.725 1.25 1.813 2.175T9.4 19.55m5.2 0q1.4-.45 2.488-1.375T18.9 16h-2.95q-.225.95-.562 1.838T14.6 19.55M4.25 14h3.4q-.075-.5-.112-.987T7.5 12t.038-1.012T7.65 10h-3.4q-.125.5-.187.988T4 12t.063 1.013t.187.987m5.4 0h4.7q.075-.5.113-.987T14.5 12t-.038-1.012T14.35 10h-4.7q-.075.5-.112.988T9.5 12t.038 1.013t.112.987m6.7 0h3.4q.125-.5.188-.987T20 12t-.062-1.012T19.75 10h-3.4q.075.5.113.988T16.5 12t-.038 1.013t-.112.987m-.4-6h2.95q-.725-1.25-1.812-2.175T14.6 4.45q.45.825.788 1.713T15.95 8M10.1 8h3.8q-.3-1.1-.775-2.075T12 4.05q-.65.9-1.125 1.875T10.1 8m-5 0h2.95q.225-.95.563-1.838T9.4 4.45Q8 4.9 6.912 5.825T5.1 8\"\u002F>",{"left":4,"top":4,"width":5,"height":5,"rotate":4,"vFlip":6,"hFlip":6,"body":19},"\u003Cpath fill=\"none\" stroke=\"currentColor\" stroke-linecap=\"round\" stroke-linejoin=\"round\" stroke-width=\"2\" d=\"m6 9l6 6l6-6\"\u002F>",{"left":4,"top":4,"width":5,"height":5,"rotate":4,"vFlip":6,"hFlip":6,"body":21},"\u003Cg fill=\"none\" stroke=\"currentColor\" stroke-linecap=\"round\" stroke-linejoin=\"round\" stroke-width=\"2\">\u003Cpath d=\"M20 13c0 5-3.5 7.5-7.66 8.95a1 1 0 0 1-.67-.01C7.5 20.5 4 18 4 13V6a1 1 0 0 1 1-1c2 0 4.5-1.2 6.24-2.72a1.17 1.17 0 0 1 1.52 0C14.51 3.81 17 5 19 5a1 1 0 0 1 1 1z\"\u002F>\u003Cpath d=\"m9 12l2 2l4-4\"\u002F>\u003C\u002Fg>",{"left":4,"top":4,"width":5,"height":5,"rotate":4,"vFlip":6,"hFlip":6,"body":23},"\u003Cg fill=\"none\" stroke=\"currentColor\" stroke-linecap=\"round\" stroke-linejoin=\"round\" stroke-width=\"2\">\u003Cpath d=\"m22 7l-8.991 5.727a2 2 0 0 1-2.009 0L2 7\"\u002F>\u003Crect width=\"20\" height=\"16\" x=\"2\" y=\"4\" rx=\"2\"\u002F>\u003C\u002Fg>",{"left":4,"top":4,"width":5,"height":5,"rotate":4,"vFlip":6,"hFlip":6,"body":25},"\u003Cg fill=\"none\" stroke=\"currentColor\" stroke-linecap=\"round\" stroke-linejoin=\"round\" stroke-width=\"2\">\u003Cpath d=\"M3 7a2 2 0 0 1 2-2h14a2 2 0 0 1 2 2v10a2 2 0 0 1-2 2H5a2 2 0 0 1-2-2z\"\u002F>\u003Cpath d=\"M7 15V9l2 2l2-2v6m3-2l2 2l2-2m-2 2V9\"\u002F>\u003C\u002Fg>",{"left":4,"top":4,"width":5,"height":5,"rotate":4,"vFlip":6,"hFlip":6,"body":27},"\u003Cpath fill=\"none\" stroke=\"currentColor\" stroke-linecap=\"round\" stroke-linejoin=\"round\" stroke-width=\"2\" d=\"m18 16l4-4l-4-4M6 8l-4 4l4 4m8.5-12l-5 16\"\u002F>",{"left":4,"top":4,"width":5,"height":5,"rotate":4,"vFlip":6,"hFlip":6,"body":29},"\u003Cg fill=\"none\" stroke=\"currentColor\" stroke-linecap=\"round\" stroke-linejoin=\"round\" stroke-width=\"2\">\u003Crect width=\"18\" height=\"18\" x=\"3\" y=\"3\" rx=\"2\"\u002F>\u003Cpath d=\"M7 3v18M3 7.5h4M3 12h18M3 16.5h4M17 3v18m0-13.5h4m-4 9h4\"\u002F>\u003C\u002Fg>",{"left":4,"top":4,"width":5,"height":5,"rotate":4,"vFlip":6,"hFlip":6,"body":31},"\u003Cg fill=\"none\" stroke=\"currentColor\" stroke-linecap=\"round\" stroke-linejoin=\"round\" stroke-width=\"2\">\u003Cpath d=\"M6 22a2 2 0 0 1-2-2V4a2 2 0 0 1 2-2h8a2.4 2.4 0 0 1 1.704.706l3.588 3.588A2.4 2.4 0 0 1 20 8v12a2 2 0 0 1-2 2z\"\u002F>\u003Cpath d=\"M14 2v5a1 1 0 0 0 1 1h5M10 9H8m8 4H8m8 4H8\"\u002F>\u003C\u002Fg>",{"left":4,"top":4,"width":5,"height":5,"rotate":4,"vFlip":6,"hFlip":6,"body":33},"\u003Cg fill=\"none\" stroke=\"currentColor\" stroke-linecap=\"round\" stroke-linejoin=\"round\" stroke-width=\"2\">\u003Cpath d=\"M21 8a2 2 0 0 0-1-1.73l-7-4a2 2 0 0 0-2 0l-7 4A2 2 0 0 0 3 8v8a2 2 0 0 0 1 1.73l7 4a2 2 0 0 0 2 0l7-4A2 2 0 0 0 21 16Z\"\u002F>\u003Cpath d=\"m3.3 7l8.7 5l8.7-5M12 22V12\"\u002F>\u003C\u002Fg>",{"left":4,"top":4,"width":5,"height":5,"rotate":4,"vFlip":6,"hFlip":6,"body":27},{"left":4,"top":4,"width":5,"height":5,"rotate":4,"vFlip":6,"hFlip":6,"body":36},"\u003Cg fill=\"none\" stroke=\"currentColor\" stroke-linecap=\"round\" stroke-linejoin=\"round\" stroke-width=\"2\">\u003Crect width=\"18\" height=\"18\" x=\"3\" y=\"3\" rx=\"2\" ry=\"2\"\u002F>\u003Ccircle cx=\"9\" cy=\"9\" r=\"2\"\u002F>\u003Cpath d=\"m21 15l-3.086-3.086a2 2 0 0 0-2.828 0L6 21\"\u002F>\u003C\u002Fg>",{"left":4,"top":4,"width":5,"height":5,"rotate":4,"vFlip":6,"hFlip":6,"body":38},"\u003Cg fill=\"none\" stroke=\"currentColor\" stroke-linecap=\"round\" stroke-linejoin=\"round\" stroke-width=\"2\">\u003Crect width=\"18\" height=\"18\" x=\"3\" y=\"3\" rx=\"2\"\u002F>\u003Cpath d=\"M16 8.9V7H8l4 5l-4 5h8v-1.9\"\u002F>\u003C\u002Fg>",{"left":4,"top":4,"width":5,"height":5,"rotate":4,"vFlip":6,"hFlip":6,"body":40},"\u003Cpath fill=\"none\" stroke=\"currentColor\" stroke-linecap=\"round\" stroke-linejoin=\"round\" stroke-width=\"2\" d=\"M6 11h4M8 9v4m7-1h.01M18 10h.01m-.69-5H6.68a4 4 0 0 0-3.978 3.59l-.017.152C2.604 9.416 2 14.456 2 16a3 3 0 0 0 3 3c1 0 1.5-.5 2-1l1.414-1.414A2 2 0 0 1 9.828 16h4.344a2 2 0 0 1 1.414.586L17 18c.5.5 1 1 2 1a3 3 0 0 0 3-3c0-1.545-.604-6.584-.685-7.258q-.01-.075-.017-.151A4 4 0 0 0 17.32 5\"\u002F>",{"left":4,"top":4,"width":5,"height":5,"rotate":4,"vFlip":6,"hFlip":6,"body":42},"\u003Cg fill=\"none\" stroke=\"currentColor\" stroke-linecap=\"round\" stroke-linejoin=\"round\" stroke-width=\"2\">\u003Cpath d=\"M11.017 2.814a1 1 0 0 1 1.966 0l1.051 5.558a2 2 0 0 0 1.594 1.594l5.558 1.051a1 1 0 0 1 0 1.966l-5.558 1.051a2 2 0 0 0-1.594 1.594l-1.051 5.558a1 1 0 0 1-1.966 0l-1.051-5.558a2 2 0 0 0-1.594-1.594l-5.558-1.051a1 1 0 0 1 0-1.966l5.558-1.051a2 2 0 0 0 1.594-1.594zM20 2v4m2-2h-4\"\u002F>\u003Ccircle cx=\"4\" cy=\"20\" r=\"2\"\u002F>\u003C\u002Fg>",{"left":4,"top":4,"width":5,"height":5,"rotate":4,"vFlip":6,"hFlip":6,"body":44},"\u003Cg fill=\"none\" stroke=\"currentColor\" stroke-linecap=\"round\" stroke-linejoin=\"round\" stroke-width=\"2\">\u003Cpath d=\"M21.42 10.922a1 1 0 0 0-.019-1.838L12.83 5.18a2 2 0 0 0-1.66 0L2.6 9.08a1 1 0 0 0 0 1.832l8.57 3.908a2 2 0 0 0 1.66 0zM22 10v6\"\u002F>\u003Cpath d=\"M6 12.5V16a6 3 0 0 0 12 0v-3.5\"\u002F>\u003C\u002Fg>","\u003Cblockquote>\n\u003Cp>A scanned contract at 30+ MB hits email's 20 MB cap and WeChat's file limits—and re-scanning is a pain. The root cause isn't "too many pages" but that scanned PDFs are essentially a stack of high-resolution images. Once you see that, you know what to compress, how small you can go, and when compression is pointless.\u003C\u002Fp>\n\u003C\u002Fblockquote>\n\u003Cp>\u003Cimg src=\"\u002Fblog\u002Fcompress-scanned-pdf\u002Fcover.webp\" alt=\"Scanned PDFs are stacks of high-res bitmaps—compression shrinks them\">\u003C\u002Fp>\n\u003Ch2>Why Are Scanned PDFs So Big?\u003C\u002Fh2>\n\u003Cp>Because scanned PDFs store \u003Cstrong>a bitmap photo per page\u003C\u002Fstrong>, not text. A scanner or phone captures the paper as an image and puts it in a PDF container—so size is driven by resolution and color depth, not word count. A blank page and a dense contract scan to roughly the same size.\u003C\u002Fp>\n\u003Cp>The math is straightforward: one A4 page at 300 DPI color scan is about 2480×3508 pixels—nearly 25 MB uncompressed. Even with basic JPEG compression from the scanner, a single page is often 1–3 MB; a dozen pages easily reach tens of MB. That's unlike Word-exported PDFs, which store text and vectors—a 50-page report may be only a few hundred KB.\u003C\u002Fp>\n\u003Cp>So the first step is telling \u003Cstrong>text-based\u003C\u002Fstrong> from \u003Cstrong>image\u002Fscanned\u003C\u002Fstrong> PDFs. The former has little room to shrink; the latter is where compression pays off.\u003C\u002Fp>\n\u003Ch2>What Does PDF Compression Actually Do?\u003C\u002Fh2>\n\u003Cp>PDF compression mainly does two things: \u003Cstrong>remove redundant structure\u003C\u002Fstrong> and \u003Cstrong>re-encode images\u003C\u002Fstrong>. For scans, the second step is what saves volume.\u003C\u002Fp>\n\u003Cul>\n\u003Cli>\u003Cstrong>Lossless optimization\u003C\u002Fstrong>: cleans duplicate objects, unused resources, and redundant metadata—tightens internal structure without changing any pixels. For pure-image PDFs, this saves little.\u003C\u002Fli>\n\u003Cli>\u003Cstrong>Image re-encoding\u003C\u002Fstrong>: resamples page bitmaps to a target resolution, then compresses with a lossy codec like JPEG. That's how a 30 MB scan can drop to a few MB—halving resolution roughly quarters the data.\u003C\u002Fli>\n\u003C\u002Ful>\n\u003Cp>A solid approach is \u003Cstrong>two-stage compression\u003C\u002Fstrong>: lossless cleanup first, then per-page image re-encoding. That avoids blindly destroying quality while getting most gains from the image layer. The \u003Ca href=\"\u002Fdocs\u002FpdfCompress\u002F\">PDF compression tool\u003C\u002Fa> follows this pattern—scanned and image PDFs often shrink to 10%–30% of the original.\u003C\u002Fp>\n\u003Ch2>How Small Can You Go Without Blurring? Picking Resolution\u003C\u002Fh2>\n\u003Cp>Key takeaway first: \u003Cstrong>150–200 DPI is enough for screen reading and normal printing\u003C\u002Fstrong>; below 100 DPI, blur becomes obvious. Match resolution to use:\u003C\u002Fp>\n\u003Ctable>\n\u003Cthead>\n\u003Ctr>\n\u003Cth>Use case\u003C\u002Fth>\n\u003Cth>Suggested resolution\u003C\u002Fth>\n\u003Cth>Notes\u003C\u002Fth>\n\u003C\u002Ftr>\n\u003C\u002Fthead>\n\u003Ctbody>\n\u003Ctr>\n\u003Ctd>WeChat\u002Femail, screen viewing\u003C\u002Ftd>\n\u003Ctd>120–150 DPI\u003C\u002Ftd>\n\u003Ctd>Smallest size; clear on screen\u003C\u002Ftd>\n\u003C\u002Ftr>\n\u003Ctr>\n\u003Ctd>Normal print, archiving\u003C\u002Ftd>\n\u003Ctd>200–300 DPI\u003C\u002Ftd>\n\u003Ctd>Sharp print, moderate size\u003C\u002Ftd>\n\u003C\u002Ftr>\n\u003Ctr>\n\u003Ctd>OCR or zooming into detail\u003C\u002Ftd>\n\u003Ctd>≥300 DPI\u003C\u002Ftd>\n\u003Ctd>Avoid heavy compression; preserve fidelity\u003C\u002Ftd>\n\u003C\u002Ftr>\n\u003C\u002Ftbody>\n\u003C\u002Ftable>\n\u003Cp>In practice, dropping a 300 DPI color scan to 150 DPI with moderate JPEG often cuts size to about 1\u002F5 of the original—barely noticeable on phones and laptops. Black-and-white text scans can also be grayscale for extra savings.\u003C\u002Fp>\n\u003Ch2>Still Too Big After Compression?\u003C\u002Fh2>\n\u003Cp>If tuning resolution still exceeds the recipient's limit, try splitting or converting:\u003C\u002Fp>\n\u003Cul>\n\u003Cli>\u003Cstrong>Too many pages\u003C\u002Fstrong>: use the \u003Ca href=\"\u002Fdocs\u002FpdfTools\u002F\">PDF split\u002Fmerge tool\u003C\u002Fa> to split by page range and send several smaller files.\u003C\u002Fli>\n\u003Cli>\u003Cstrong>They only need to view, not keep PDF\u003C\u002Fstrong>: use \u003Ca href=\"\u002Fdocs\u002FpdfToImages\u002F\">PDF to images\u003C\u002Fa> to export needed pages as JPG—often smaller and easier to open.\u003C\u002Fli>\n\u003Cli>\u003Cstrong>The scan was already blurry\u003C\u002Fstrong>: low resolution at capture can't be fixed by compression—re-scan instead.\u003C\u002Fli>\n\u003C\u002Ful>\n\u003Ch2>When Compression Won't Help\u003C\u002Fh2>\n\u003Cp>Compression isn't universal. These cases yield little or nothing:\u003C\u002Fp>\n\u003Cul>\n\u003Cli>\u003Cstrong>Text\u002Fvector PDFs\u003C\u002Fstrong>: Word\u002Fweb exports are already small with no large images—maybe a few percent smaller.\u003C\u002Fli>\n\u003Cli>\u003Cstrong>Already compressed once\u003C\u002Fstrong>: re-compressing degrades quality further with minimal size gain.\u003C\u002Fli>\n\u003Cli>\u003Cstrong>Heavy vector graphics\u002Ftables\u003C\u002Fstrong>: already efficiently encoded; image resampling doesn't apply.\u003C\u002Fli>\n\u003C\u002Ful>\n\u003Cp>Simple rule: \u003Cstrong>big PDFs are almost always image-based—compress those; small text PDFs aren't worth the effort.\u003C\u002Fstrong>\u003C\u002Fp>\n\u003Ch2>Summary\u003C\u002Fh2>\n\u003Cp>Scanned PDFs are large because they're stacks of high-resolution images—size follows resolution and color depth, not word count. Compression means \u003Cstrong>lossless cleanup first, then resample images to 150–200 DPI for your use case and re-encode\u003C\u002Fstrong>—screen viewing often reaches 10%–30% of original size with little visible loss. When that fails, try \u003Ca href=\"\u002Fdocs\u002FpdfTools\u002F\">splitting\u003C\u002Fa> or \u003Ca href=\"\u002Fdocs\u002FpdfToImages\u002F\">converting to images\u003C\u002Fa>; pure text PDFs are already small. Processing runs locally in the browser—contracts and ID scans never need to be uploaded.\u003C\u002Fp>\n",{"left":4,"top":4,"width":5,"height":5,"rotate":4,"vFlip":6,"hFlip":6,"body":47},"\u003Cpath fill=\"none\" stroke=\"currentColor\" stroke-linecap=\"round\" stroke-linejoin=\"round\" stroke-width=\"2\" d=\"M15 14c.2-1 .7-1.7 1.5-2.5c1-.9 1.5-2.2 1.5-3.5A6 6 0 0 0 6 8c0 1 .2 2.2 1.5 3.5c.7.7 1.3 1.5 1.5 2.5m0 4h6m-5 4h4\"\u002F>",{"left":4,"top":4,"width":5,"height":5,"rotate":4,"vFlip":6,"hFlip":6,"body":49},"\u003Cpath fill=\"none\" stroke=\"currentColor\" stroke-linecap=\"round\" stroke-linejoin=\"round\" stroke-width=\"2\" d=\"m14 10l7-7m-1 7h-6V4M3 21l7-7m-6 0h6v6\"\u002F>",{"left":4,"top":4,"width":5,"height":5,"rotate":4,"vFlip":6,"hFlip":6,"body":51},"\u003Cg fill=\"none\" stroke=\"currentColor\" stroke-linecap=\"round\" stroke-linejoin=\"round\" stroke-width=\"2\">\u003Cpath d=\"M10.3 21H5a2 2 0 0 1-2-2V5a2 2 0 0 1 2-2h14a2 2 0 0 1 2 2v10l-3.1-3.1a2 2 0 0 0-2.814.014L6 21\"\u002F>\u003Cpath d=\"m14 19l3 3v-5.5m0 5.5l3-3\"\u002F>\u003Ccircle cx=\"9\" cy=\"9\" r=\"2\"\u002F>\u003C\u002Fg>",1782539672615]