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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.