How Photoshop saves the resolution in TIFF files.
The Photoshop image editing software saves the resolution in TIFF files in two places:
- EXIF-Tags
- X-resolution: 0x011A
- Y-resolution: 0x011B
- Data type: Rational
- Unit: dpi/Inch or dpi/cm, depending on EXIF tag 0x0128
- Photoshop Resolution Tag
This tag is part of the Photoshop Image Resource Block (EXIF tag= 0x8649). Within this block the resolution information is located at tag 0x03ed.
- Structure: See here…
- Data type X/YResolution = int32u
- XResolution = X-Auflösung (float, double, decimal) * 65536
If Photoshop reads a TIFF-file and
- 1) and 2) are present, Photoshop uses the values from 2).
- If only 1) is present, Photoshop uses the values from 1).
I.e., if a TIFF file is saved and the TIFF metadata contains a Photoshop Image Resource block, the resolutions (X/YResolution) must also be set correctly in 2).