2011.11.30 11:23 "[Tiff] Inconsistent metadata report for CMYK 8-bit image", by Mateusz_Łoskot

2011.11.30 11:23 "[Tiff] Inconsistent metadata report for CMYK 8-bit image", by Mateusz_Łoskot

Hi,

I have a CMYK TIFF image and I'm having problems to identify what is its actual configuration.

I'm not sure if I can post images as attachment to the list, so I uploaded it to my server:

http://mateusz.loskot.net/tmp/Shadow_cmyk8.tif (2.6 MB)
http://mateusz.loskot.net/tmp/Shadow_cmyk8.zip (0.5 MB)

I have tried three different tools and each of them reports slightly different configuration:

#################################################################### 1) tiffinfo (libtiff 4.0.0 Beta7 (32-bit build on Windows 64-bit))

C:\> tiffinfo Shadow_cmyk8.tif

Unknown field with tag 37724 (0x935c) encountered.

TIFF Directory at offset 0x8 (8)
    Subfile Type: (0 = 0x0)
    Image Width: 768 Image Length: 505
    Resolution: 72, 72 pixels/inch
    Bits/Sample: 8
    Compression Scheme: None
    Photometric Interpretation: separated
    Extra Samples: 1<assoc-alpha>
    Orientation: row 0 top, col 0 lhs
    Samples/Pixel: 5
    Rows/Strip: 505
    Planar Configuration: single image plane

  Software: Adobe Photoshop CS3 Windows
  DateTime: 2011:10:31 14:09:04
  XMLPacket (XMP Metadata):
...

#################################################################### 2) gdalinfo (from current OSGeo4W package)

C:\> gdalinfo Shadow_cmyk8.tif

Warning 1: TIFFReadDirectory:Unknown field with tag 37724 (0x935c) encountered Driver: GTiff/GeoTIFF

Files: Shadow_cmyk8.tif
Size is 768, 505
Coordinate System is `'
Metadata:
  TIFFTAG_SOFTWARE=Adobe Photoshop CS3 Windows
  TIFFTAG_DATETIME=2011:10:31 14:09:04
  TIFFTAG_XRESOLUTION=72
  TIFFTAG_YRESOLUTION=72
  TIFFTAG_RESOLUTIONUNIT=2 (pixels/inch)
Image Structure Metadata:
  SOURCE_COLOR_SPACE=CMYK
  INTERLEAVE=PIXEL
Corner Coordinates:

Upper Left  (    0.0,    0.0)
Lower Left  (    0.0,  505.0)
Upper Right (  768.0,    0.0)
Lower Right (  768.0,  505.0)
Center      (  384.0,  252.5)
Band 1 Block=768x2 Type=Byte, ColorInterp=Red

  Mask Flags: PER_DATASET ALPHA
Band 2 Block=768x2 Type=Byte, ColorInterp=Green
  Mask Flags: PER_DATASET ALPHA
Band 3 Block=768x2 Type=Byte, ColorInterp=Blue
  Mask Flags: PER_DATASET ALPHA
Band 4 Block=768x2 Type=Byte, ColorInterp=Alpha

####################################################################
3) identify from ImageMagick 6.7.3

C>identify -verbose Shadow_cmyk8.tif
Image: Shadow_cmyk8.tif
  Format: TIFF (Tagged Image File Format)
  Class: DirectClass
  Geometry: 768x505+0+0
  Resolution: 72x72
  Print size: 10.6667x7.01389
  Units: PixelsPerInch
  Type: ColorSeparationMatte
  Base type: ColorSeparation
  Endianess: MSB
  Colorspace: CMYK
  Depth: 8/16-bit
  Channel depth:
    cyan: 16-bit
    magenta: 16-bit
    yellow: 16-bit
    black: 8-bit
    alpha: 8-bit
  Channel statistics:
    Cyan:
      min: 0 (0)
      max: 255 (1)
      mean: 30.1219 (0.118125)
      standard deviation: 81.5185 (0.31968)
      kurtosis: 3.67711
      skewness: 2.37807
    Magenta:
      min: 0 (0)
      max: 255 (1)
      mean: 69.7906 (0.273689)
      standard deviation: 113.31 (0.444351)
      kurtosis: -0.984415
      skewness: 1.00769
    Yellow:
      min: 0 (0)
      max: 250 (0.980392)
      mean: 43.7205 (0.171453)
      standard deviation: 89.2673 (0.350068)
      kurtosis: 1.31287
      skewness: 1.78273
    Black:
      min: 0 (0)
      max: 24 (0.0941176)
      mean: 1.10718 (0.00434189)
      standard deviation: 4.21034 (0.0165111)
      kurtosis: 16.1728
      skewness: 4.11968
    Alpha:
      min: 0 (0)
      max: 255 (1)
      mean: 46.9553 (0.184138)
      standard deviation: 93.2179 (0.36556)
      kurtosis: 0.885903
      skewness: -1.64831
  Image statistics:
    Overall:
      min: 0 (0)
      max: 255 (1)
      mean: 70.557 (0.276694)
      standard deviation: 85.0415 (0.333496)
      kurtosis: 3.04391
      skewness: 2.26633
  Total ink density: 233%
  Alpha: cmyka(0,0,0,0,0)   #0000000000
  Rendering intent: Undefined
  Interlace: None
  Background color: cmyka(255,255,255,0,1)
  Border color: cmyka(223,223,223,0,1)
  Matte color: cmyka(189,189,189,0,1)
  Transparent color: cmyka(0,0,0,0,0)
  Compose: Over
  Page geometry: 768x505+0+0
  Dispose: Undefined
  Iterations: 0
  Compression: None
  Orientation: TopLeft
  Properties:
...
####################################################################

Which one is right?

How many bits per sample and how many samples per pixel is there?

Best regards,

--
Mateusz Loskot, http://mateusz.loskot.net
Charter Member of OSGeo, http://osgeo.org
Member of ACCU, http://accu.org