{"id":"image-x-rgb","mimeType":"image/x-rgb","name":"Silicon Graphics Image","shortName":"SGI-RGB","category":"Legacy \u0026 Raster Graphics","extensions":[".rgb",".sgi",".rgba",".bw",".int",".inta"],"description":"The image/x-rgb MIME type represents the Silicon Graphics Image (SGI) format, frequently referred to as the RGB format. Developed by Paul Haeberli at Silicon Graphics, Inc. (SGI) in the late 1980s for the IRIX workstation operating system, this raster format became an industry standard for high-end 3D rendering, animation, and visual effects software during the 1990s (such as Alias PowerAnimator and early versions of Maya). The format supports anywhere from 1 to 4 color channels (Grayscale, Grayscale+Alpha, RGB, RGBA) at 8 or 16 bits per channel, and can store pixels either completely uncompressed or using a highly efficient, scanline-based Run-Length Encoding (RLE) algorithm.","seo":{"title":"image/x-rgb MIME Type | Developer Reference for SGI RGB","description":"Complete reference for the image/x-rgb MIME type: Silicon Graphics Image (SGI) format, IRIX workstations, RLE compression, and 3D rendering history.","faqs":[{"question":"What is an SGI RGB file?","answer":"An SGI or RGB file is a legacy raster image format created by Silicon Graphics. It was heavily used in the 1990s by professional 3D animation, CAD, and visual effects software to store rendered frames and textures."},{"question":"What is the difference between .sgi, .rgb, and .bw files?","answer":"They represent exactly the same file format. The different extensions were historically used as a naming convention by Unix users to indicate the number of color channels inside the file without having to parse the header: .bw for 1-channel grayscale, .rgb for 3-channel color, and .rgba for 4-channel color with transparency."},{"question":"How can I view an image/x-rgb file?","answer":"Modern web browsers and most default operating system image viewers do not support the SGI format natively. You must use image editing software like GIMP, ImageMagick, or XnView to open them or convert them to modern formats like PNG or JPEG."}]},"index":{"compression":["Uncompressed","Run-Length Encoding (RLE)"],"browserSupport":{"score":1,"label":"None"},"commonUses":["Legacy 3D Animation and VFX Textures","Silicon Graphics IRIX Workstation Archival","1990s Medical Imaging"]},"technical":{"magicBytes":{"hex":"01 DA","ascii":"\\x01\\xDA"},"container":"SGI Image Header (512 bytes)","compressionAlgorithm":["None","Scanline RLE"],"colorDepth":["8-bit (Per Channel)","16-bit (Per Channel)"],"transparency":true,"animation":false,"metadata":{"exif":false,"xmp":false,"iccProfile":false},"alphaChannel":true,"progressiveLoading":false,"hdrSupport":false},"history":{"developer":"Silicon Graphics, Inc. (Paul Haeberli)","released":"1988","specification":"The SGI Image File Format Document"},"browserSupport":{"chrome":false,"chromeVersion":"None","firefox":false,"firefoxVersion":"None","safari":false,"safariVersion":"None","edge":false,"edgeVersion":"None","internetExplorer":false},"softwareSupport":[{"name":"ImageMagick","logo":"image-magic.webp"},{"name":"GIMP","logo":"gimp.svg"},{"name":"XnView","logo":""},{"name":"FFmpeg","logo":""}],"conversion":{"convertTo":["png","jpeg","tiff","tga"],"convertFrom":["tga","tiff"]},"developer":{"httpHeaders":[{"header":"Content-Type","value":"image/x-rgb"},{"header":"Content-Type","value":"image/x-sgi"}],"htmlAccept":"image/x-rgb, .rgb, .sgi, .rgba, .bw","fileDetection":["Every valid SGI image file begins with a 2-byte 'magic number'. Check the first 2 bytes for the value 474 (Decimal), which translates to the bytes 0x01 and 0xDA in Hexadecimal.","Byte 2 (Offset 2) indicates the storage format: 0 means verbatim (uncompressed) and 1 means RLE compressed.","Byte 3 (Offset 3) indicates the Bytes Per Pixel Channel (BPC), which is almost universally 1 or 2 (representing 8-bit or 16-bit color precision).","Be extremely cautious of the .rgb extension on older FTP servers, as it was sometimes misused for raw interleaved pixel dumps lacking the 512-byte SGI header entirely."]},"prosCons":{"pros":["Supports 16-bit precision per channel and an embedded alpha channel, making it ideal for the demanding compositing workflows of 1990s cinema VFX","The scanline-based RLE compression was exceptionally fast to decode on classic MIPS-based SGI workstations","Features a straightforward 512-byte header, making it relatively easy to parse and write custom decoders in C or Python"],"cons":["Completely obsolete and unsupported in modern web environments","Replaced entirely by TIFF, OpenEXR, and PNG in modern visual effects and 3D rendering pipelines","Lacks support for modern color management via ICC profiles or advanced EXIF metadata"]},"specifications":{"url":"https://paulbourke.net/dataformats/sgirgb/","rfc":"","mimeAliases":["image/rgb","image/x-sgi","image/sgi"]},"developerSnippets":{"python":"import magic\n# Libmagic can easily detect the SGI magic bytes\nprint(magic.from_file('texture.sgi', mime=True)) # Outputs 'image/x-rgb' or 'image/x-sgi'","nodejs":"const fs = require('fs');\n// Manually detecting the SGI magic header (0x01DA)\nconst buffer = Buffer.alloc(2);\nconst fd = fs.openSync('texture.rgb', 'r');\nfs.readSync(fd, buffer, 0, 2, 0);\nfs.closeSync(fd);\nconst isSGI = buffer[0] === 0x01 \u0026\u0026 buffer[1] === 0xDA;\nconsole.log('Is Silicon Graphics RGB Image:', isSGI);","go":"import (\n    \"bytes\"\n    \"net/http\"\n)\n// Native Go HTTP detection does not recognize SGI RGB.\n// You must explicitly check the first two bytes:\n// isSGI := len(buf) \u003e= 2 \u0026\u0026 buf[0] == 0x01 \u0026\u0026 buf[1] == 0xDA","php":"$mime = mime_content_type('texture.rgb');\necho $mime; // Standard PHP setups will return 'image/x-rgb' depending on the system magic database"},"relatedFormats":["tga","tiff"]}