2020.08.16 15:34 "Re: [Tiff] Problems with Photoshop when a file is written is strips", by David C. Partridge

I said:

I'm not writing any 16 bit half float files - my output file is strictly 32 bit floating point. GIMP and PS and IrfanView are all happy to read my 32 bit output files.

The problem is that when written using PREDICTIVE compression, PS was happy to read it, BUT when it converted to 16 bit and then wrote a new TIFF, things went pear shaped.

That 16 bit output file was completely unreadable by all the applications I have except for PS itself.

Bob Friesenhahn replied:

>What does libtiff's tiffinfo have to say about the new TIFF where things went "pear shaped"?

>I am not sure what PREDICTIVE compression might mean.

Predictive compression - I'm referring to this:

TIFFSetField(m_tiff, TIFFTAG_PREDICTOR, PREDICTOR_FLOATINGPOINT);

tiffinfo says:

>tiffinfo broken.tif

TIFFReadDirectory: Warning, Unknown field with tag 317 (0x13d) encountered.
broken.tif: AdobeDeflate compression support is not configured.

TIFF Directory at offset 0x8 (8)
  Subfile Type: (0 = 0x0)
  Image Width: 4144 Image Length: 2822
  Resolution: 100, 100 pixels/inch
  Bits/Sample: 16
  Compression Scheme: AdobeDeflate
  Photometric Interpretation: RGB color
  Orientation: row 0 top, col 0 lhs
  Samples/Pixel: 3
  Rows/Strip: 42
  Planar Configuration: single image plane
  Software: Adobe Photoshop 21.0 (Windows)
  DateTime: 2020:08:16 16:20:49
  Tag 317: 3
  XMLPacket (XMP Metadata):
<?xpacket begin="´╗┐" id="W5M0MpCehiHzreSzNTczkc9d"?>
<x:xmpmeta xmlns:x="adobe:ns:meta/" x:xmptk="Adobe XMP Core 5.6-c148 79.164036, 2019/08/13-01:06:57 ">
   <rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#">
      <rdf:Description rdf:about=""
            xmlns:xmp="http://ns.adobe.com/xap/1.0/"
            xmlns:dc="http://purl.org/dc/elements/1.1/"
            xmlns:photoshop="http://ns.adobe.com/photoshop/1.0/"
            xmlns:xmpMM="http://ns.adobe.com/xap/1.0/mm/"
            xmlns:stEvt="http://ns.adobe.com/xap/1.0/sType/ResourceEvent#">
         <xmp:CreatorTool>Adobe Photoshop 21.0 (Windows)</xmp:CreatorTool>
         <xmp:ModifyDate>2020-08-16T16:20:49+01:00</xmp:ModifyDate>
         <xmp:CreateDate>2020-08-15T17:41:20+01:00</xmp:CreateDate>
         <xmp:MetadataDate>2020-08-16T16:20:49+01:00</xmp:MetadataDate>
         <dc:format>image/tiff</dc:format>
         <photoshop:ColorMode>3</photoshop:ColorMode>
         <photoshop:ICCProfile>sRGB IEC61966-2.1</photoshop:ICCProfile>
         <xmpMM:InstanceID>xmp.iid:76928267-d2d6-6f4d-8fbf-251d500a61be</xmpMM:InstanceID>
         <xmpMM:DocumentID>adobe:docid:photoshop:81e95446-e372-c248-80c4-7552968b1a98</xmpMM:DocumentID>
         <xmpMM:OriginalDocumentID>xmp.did:04b91f9b-aaca-5a4e-9dfd-1a8032de2b5e</xmpMM:OriginalDocumentID>
         <xmpMM:History>
            <rdf:Seq>
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                  <stEvt:action>created</stEvt:action>
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                  <stEvt:when>2020-08-15T17:41:20+01:00</stEvt:when>
                  <stEvt:softwareAgent>Adobe Photoshop 21.0 (Windows)</stEvt:softwareAgent>
               </rdf:li>
               <rdf:li rdf:parseType="Resource">
                  <stEvt:action>saved</stEvt:action>
                  <stEvt:instanceID>xmp.iid:76928267-d2d6-6f4d-8fbf-251d500a61be</stEvt:instanceID>
                  <stEvt:when>2020-08-16T16:20:49+01:00</stEvt:when>
                  <stEvt:softwareAgent>Adobe Photoshop 21.0 (Windows)</stEvt:softwareAgent>
                  <stEvt:changed>/</stEvt:changed>
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            </rdf:Seq>
         </xmpMM:History>
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</x:xmpmeta>

<?xpacket end="w"?>
  Photoshop Data: <present>, 3380 bytes
  EXIFIFDOffset: 0x27f026c
  ICC Profile: <present>, 3144 bytes
TIFF Directory at offset 0x27f026c (41878124)
  ColorSpace: 1
  PixelXDimension: 4144
  PixelYDimension: 2822

David