O cabeçalho é de 8 bytes:
+------------------------------------------------------------------------+
| TIFF Header |
+--------+-------+----------+--------------------------------------------+
| Offset | Type | Default | Description |
+--------+-------+----------+--------------------------------------------+
| 0-1 | WORD | II or MM | Endian: Intel (little) / Motorola (big) |
| 2-3 | WORD | 0x2A | Version (usually 42) |
| 4-7 | ULONG | | Offset to first IFD (image file directory) |
+--------+-------+----------+--------------------------------------------+
Veja algumas referências: