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- How GIMP should handle EXIF data
- Bill Skaggs 1/2/05
- This is a summary of how an image editing program is supposed to
- handle each of the EXIF fields, according to the EXIF specs. Note
- that this expresses my understanding based on a quick reading, and
- should not be taken as gospel. For details on the contents of each of
- these fields, consult the formal EXIF specifications, available from
- http://www.exif.org/specifications.html.
- (Note: according to the EXIF specs, an EXIF jpeg file must have a name
- that is ASCII, in 8.3 format, with extension .JPG, but of course we
- are not going to enforce this.)
- Fields that should be used to set up the GIMP image when an EXIF file
- is loaded, either by using them to configure the image (e.g.,
- orientation), or by placing them in parasites that can be accessed by
- non-exif-aware functions.
- Orientation
- XResolution
- YResolution
- ResolutionUnit
- ImageDescription
- Artist
- Copyright
- Colorspace
- ComponentsConfiguration
- UserComment
- SubjectArea
- SubjectLocation
- ImageUniqueID
- PixelXDimension
- PixelYDimension
- Fields that should be modified by GIMP when an EXIF jpeg file is
- saved. A letter "M" indicates fields whose presence is mandatory
- according to the spec.
- Orientation
- XResolution (M)
- YResolution (M)
- ResolutionUnit (M)
- Software
- DateTime
- ImageDescription
- Artist
- Colorspace (M)
- PixelXDimension (M)
- PixelYDimension (M)
- ComponentsConfiguration (M)
- UserComment
- SubsecTime
- SubjectArea
- SubjectLocation
- FileSource
- ImageUniqueID
- thumbnail Compression (M)
- thumbnail XResolution (M)
- thumbnail YResolution (M)
- thumbnail JPEGInterchangeFormat (M)
- thumbnail JPEGInterchangeFormatLength (M)
- Fields that should be used and saved related to color management:
- TransferFunction
- WhitePoint
- PrimaryChromaticity
- YCbCrCoefficients
- ReferenceBlackWhite
- Fields that should be deleted if they exist when saving a file as
- jpeg, because they only apply to uncompressed (TIFF) data. This
- applies both to the main image and to the thumbnail, if there is one.
- ImageWidth
- ImageLength
- BitsPerSample
- Compression
- SamplesPerPixel
- PhotometricInterpretation
- StripOffsets
- PlanarConfiguration
- YCbCrSubSampling
- Any field not mentioned here should be passed through unchanged.
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