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                                             256
CHAPTER 4                                                                  Graphics



color space families, the resulting colors are expected to be rendered similarly,
regardless of the method selected for representation.

One particular color space is the so-called “standard RGB” or sRGB, defined in
the International Electrotechnical Commission (IEC) document Colour Measure-
ment and Management in Multimedia Systems and Equipment (see the Bibliogra-
phy). In PDF, the sRGB color space can be expressed precisely only as an
ICCBased space, although it can be approximated by a CalRGB space.

Example 4.9 shows an ICCBased color space for a typical three-component RGB
space. The profile’s data has been encoded in hexadecimal representation for
readability; in actual practice, a lossless decompression filter such as FlateDecode
should be used.

Example 4.9

  10 0 obj                                    % Color space
     [ /ICCBased 15 0 R ]
  endobj

  15 0 obj                                    % ICC profile stream
      << /N 3
         /Alternate /DeviceRGB
         /Length 1605
         /Filter /ASCIIHexDecode
      >>
  stream
  00 00 02 0C 61 70 70 6C 02       00   00   00 6D 6E 74 72
  52 47 42 20 58 59 5A 20 07       CB   00   02 00 16 00 0E
  00 22 00 2C 61 63 73 70 41       50   50   4C 00 00 00 00
  61 70 70 6C 00 00 04 01 00       00   00   00 00 00 00 02
  00 00 00 00 00 00 F6 D4 00       01   00   00 00 00 D3 2B
  00 00 00 00 00 00 00 00 00       00   00   00 00 00 00 00
  00 00 00 00 00 00 00 00 00       00   00   00 00 00 00 00
  00 00 00 00 00 00 00 00 00       00   00   00 00 00 00 00
  00 00 00 09 64 65 73 63 00       00   00   F0 00 00 00 71
  72 58 59 5A 00 00 01 64 00       00   00   14 67 58 59 5A
  00 00 01 78 00 00 00 14 62       58   59   5A 00 00 01 8C
  00 00 00 14 72 54 52 43 00       00   01   A0 00 00 00 0E
  67 54 52 43 00 00 01 B0 00       00   00   0E 62 54 52 43
  00 00 01 C0 00 00 00 0E 77       74   70   74 00 00 01 D0
  00 00 00 14 63 70 72 74 00       00   01   E4 00 00 00 27
  64 65 73 63 00 00 00 00 00       00   00   17 41 70 70 6C

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