JEITA  CP-3451 - 13 - 4.6    Tags 4.6.1   Features of Attribute Information RGB  data  conforms  to  Baseline  TIFF  Rev.  6.0  RGB  Full  Color  Images,  and  YCbCr  data  to  TIFF  Rev.  6.0 Extensions YCbCr Images. Accordingly, the parts that follow the TIFF structure shall be recorded in conformance to the TIFF standard. In addition to the attribute information  indicated as mandatory in the TIFF standard, this Exif standard adds the TIFF optional tags that can be used in a DSC or other system, Exif-specific tags for recording DSC-specific  attribute  information,  and  GPS  tags  for  recording  position  information.  There  are  also  Exif-original specifications not found in the TIFF standard for compressed recording of thumbnails. Recording of compressed data differs from uncompressed data in the following respects: ·  When the primary image data is recorded in compressed form, there is no tag indicating the primary image itself or its address (pointer), ·  When  thumbnail  data  is  recorded  in  compressed  form,  address  and  size  are  designated  using  Exif-specific tags, ·  Tags  that  duplicate  information  given  in  the  JPEG  Baseline  are  not  recorded  (for  either  primary  images  or thumbnails). ·  Information relating to compression can be recorded using the tags for this purpose.   4.6.2   IFD Structure The IFD used in this standard consists of a 2-byte count (number of fields), 12-byte field Interoperability arrays, and 4-byte offset to the next IFD, in conformance with TIFF Rev. 6.0. Each of the 12-byte field Interoperability consists of the following four elements respectively. Bytes 0-1   Tag Bytes 2-3 Type Bytes 4-7 Count Bytes 8-11 Value Offset Each element is explained briefly below. For details see TIFF Rev. 6.0.