Tagged Image File Format
TIFF stores high-fidelity raster images with flexible compression (LZW, DEFLATE, JPEG, or none), multi-page support, and rich metadata — the standard format for print production, medical imaging, GIS, and archival workflows where quality and structure matter more than file size.
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أسئلة شائعة
Why can't I view TIFF images in Chrome or Firefox?
Chrome, Firefox, and Edge do not include a built-in TIFF decoder. TIFF's complexity (multiple compression algorithms, color spaces, tile modes, and multi-page support) exceeds what browser vendors implement for web image formats. Convert TIFF to PNG or JPG for web display.
Is TIFF or PNG better for archival storage?
TIFF is the archival standard for libraries, museums, and medical imaging because it supports CMYK, 16-bit depth, multi-page documents, and multiple lossless compression options. PNG works for single-image RGB archival but lacks TIFF's structural flexibility.
Does converting TIFF to JPG lose quality?
Yes. JPEG applies DCT lossy compression, discarding high-frequency detail. For photographic content, the loss is minimal at quality 90+. For documents, line art, or graphics with sharp edges, JPEG introduces visible blocking artifacts — use PNG instead.
What is BigTIFF and when do I need it?
BigTIFF is a 2004 extension that uses 8-byte offsets instead of 4-byte, allowing TIFF files larger than 4 GB. Medical scanners, satellite imaging, and high-resolution panoramic captures routinely exceed 4 GB and require BigTIFF. Standard TIFF cannot address data beyond the 4 GB boundary.
ما يميز .TIFF
Tagged Image File Format stores pixels alongside an extensible tag-based metadata system that has made it the archival and professional imaging standard for four decades. Aldus Corporation (later acquired by Adobe) published TIFF Revision 6.0 in 1992, and that specification remains current — no revision 7 has ever been released. TIFF files can use either little-endian (II, Intel) or big-endian (MM, Motorola) byte ordering, indicated by the first two bytes of the file. This dual-endianness was radical in 1986 when the format debuted and remains unusual among image formats today.
اكتشف التفاصيل التقنية
File structure and IFD chain
A TIFF file begins with an 8-byte header:
| Offset | Size | Field |
|---|---|---|
| 0 | 2 | Byte order ("II" or "MM") |
| 2 | 2 | Magic number (42) |
| 4 | 4 | Offset to first IFD |
The magic number 42 was chosen deliberately by the format's creators — it is, after all, the answer to everything. Each Image File Directory (IFD) is an array of 12-byte tag entries followed by a 4-byte pointer to the next IFD, forming a linked list. A single TIFF can contain multiple images (pages) by chaining IFDs.
Each tag entry holds a tag ID, data type, count, and either the value itself (if it fits in 4 bytes) or an offset to the value elsewhere in the file. Over 80 baseline tags are defined, covering dimensions, compression, photometric interpretation, strip offsets, resolution, and color space information.
Compression options
TIFF supports more compression schemes than any other image format:
| Compression | Tag value | Type | Typical use |
|---|---|---|---|
| None | 1 | Uncompressed | Raw sensor data |
| LZW | 5 | Lossless | General purpose |
| JPEG | 7 | Lossy | Photography |
| ZIP/Deflate | 8 | Lossless | GIS and mapping |
| CCITT Group 4 | 4 | Lossless | Fax and documents |
| PackBits | 32773 | Lossless | Mac compatibility |
LZW compression was patent-encumbered until 2004 (the Unisys patent), which drove the creation of PNG as a web-friendly alternative. Today LZW-compressed TIFF is the most common variant in print workflows.
Color depth and HDR
TIFF handles bit depths from 1-bit bilevel through 8-bit and 16-bit integer to 32-bit floating-point per channel. A 16-bit TIFF stores 65,536 tonal levels per channel compared to JPEG's 256. This matters for photography: a 16-bit TIFF from a raw conversion preserves highlight and shadow detail through multiple rounds of editing without banding.
CMYK, Lab, and multi-channel spot color data all fit natively in TIFF. Print shops receive TIFF files with embedded ICC profiles specifying exact color reproduction targets. A press-ready TIFF/IT-P1 file (ISO 12639) is still the gold standard for magazine advertising submission.
GeoTIFF and scientific extensions
GeoTIFF embeds geographic coordinate metadata using reserved TIFF tags (33550, 33922, 34735-34737). Satellite imagery, aerial photography, and topographic maps use GeoTIFF as the primary distribution format. A single Landsat 8 scene is a set of GeoTIFF files totaling 800 MB to 2 GB, one per spectral band.
Medical imaging uses TIFF for histopathology slides. A whole-slide image can exceed 100,000 x 100,000 pixels, stored as a tiled pyramid TIFF with multiple resolution levels. The BigTIFF extension (using 8-byte offsets instead of 4-byte) supports files larger than 4 GB, which standard TIFF cannot.
Performance and file sizes
An uncompressed 4K (3840x2160) RGB 16-bit TIFF weighs 47.5 MB. LZW compression reduces this to 15-35 MB depending on image complexity. Photographic content compresses less than synthetic graphics.
TIFF decode speed depends entirely on the compression method. Uncompressed TIFF reads as fast as the storage subsystem allows. LZW decompression runs at 200-400 MB/s on a single CPU core. JPEG-in-TIFF is the slowest to decode but produces the smallest files for photographic content.
Converting TIFF files
FileDex converts TIFF to PNG, JPEG, or WebP in the browser. Multi-page TIFFs can be split into individual images. The conversion strips CMYK data by default (converting to sRGB) since browsers cannot display CMYK. For print workflows, preserve the original TIFF — lossy conversion destroys the wide-gamut, high-bit-depth data that makes TIFF valuable.
حوّل .TIFF إلى...
المرجع التقني
- نوع MIME
image/tiff- Magic Bytes
49 49 2A 00Little-endian (II) TIFF. Big-endian uses 4D 4D 00 2A.- المطوّر
- Aldus (now Adobe)
- سنة التقديم
- 1986
- معيار مفتوح
- نعم
Little-endian (II) TIFF. Big-endian uses 4D 4D 00 2A.
البنية الثنائية
TIFF files begin with an 8-byte header: 2-byte byte order mark (49 49 for little-endian, 4D 4D for big-endian), 2-byte magic number (42 decimal, encoded per byte order), and a 4-byte offset to the first IFD. Each Image File Directory (IFD) contains a 2-byte entry count followed by 12-byte directory entries (tag ID, data type, value count, value or offset). IFDs are chained — the last 4 bytes of each IFD point to the next IFD offset (0 if no more pages). Image data is stored as strips or tiles, with StripOffsets/StripByteCounts or TileOffsets/TileByteCounts tags pointing to the compressed or raw pixel data. BigTIFF extends the header to 16 bytes with 8-byte offsets, supporting files over 4 GB.
| Offset | Length | Field | Example | Description |
|---|---|---|---|---|
0x00 | 2 bytes | Byte order | 49 49 | Byte order mark. 49 49 (II) = little-endian (Intel). 4D 4D (MM) = big-endian (Motorola). |
0x02 | 2 bytes | Magic number | 2A 00 | Always 42 (0x002A). Encoded per the byte order specified at offset 0x00. |
0x04 | 4 bytes | IFD offset | 08 00 00 00 | Byte offset to first IFD from file start. Typically 8 (immediately after header). |
IFD+0 | 2 bytes | IFD entry count | 0E 00 | Number of 12-byte directory entries in this IFD. |
IFD+2 | 12 bytes each | IFD entry | 00 01 03 00 01 00 00 00 00 04 00 00 | Tag 0x0100 (ImageWidth), type SHORT, count 1, value 1024. Each entry: 2-byte tag, 2-byte type, 4-byte count, 4-byte value/offset. |
نقاط الضعف
- Crafted IFD entries with circular offset references can trigger infinite loops in parsers
- Malformed strip/tile offsets and byte counts enable out-of-bounds memory reads
- JPEG-in-TIFF with oversized DCT coefficients can trigger decoder buffer overflows (CVE-2006-3459 class)
- Integer overflow in StripByteCounts or ImageWidth fields causes heap corruption in vulnerable libtiff versions
الحماية: FileDex does not decode TIFF natively in the browser. TIFF is a reference-only page. For conversion workflows, server-side or native tools with updated libtiff should be used.