2013.06.14 17:58 "Re: [Tiff] TIFF Specification Allowance for Multi-Page vs. Reduced Res 2nd IFD", by Frank Warmerdam

Douglas,

I have run tiffinfo on the file and amoung the tags I see:

    SubIFD Offsets: 79455156

If I rerun tiffinfo like this:

tiffinfo -o 79455156 1_120ASPH_f8_2900ppi_99eff-imagepyramid.tif

I see;

 TIFFFetchNormalTag: Warning, Incompatible type for "RichTIFFIPTC"; tag
ignored.

TIFF Directory at offset 0x4bc63b4 (79455156)
    Subfile Type: reduced-resolution image (1 = 0x1)
    Image Width: 3880 Image Length: 5164
    Resolution: 150, 150 pixels/inch
    Bits/Sample: 8
    Compression Scheme: LZW
    Photometric Interpretation: RGB color
    Orientation: row 0 top, col 0 lhs
    Samples/Pixel: 3
    Rows/Strip: 22
    Planar Configuration: single image plane

  Predictor: horizontal differencing 2 (0x2)

So this seems to be a subifd pyramid level. It strickes me as slightly odd that there is only one overview level and it is just a 2x2 downsampling but it is a pyramid level. I observe that my GDAL library does *not* honour this sort of overview via SubIFD which is sad. I likely ought to fix that.

Best regards,
Frank

On Fri, Jun 14, 2013 at 10:20 AM, Douglas Peterson < dep@digitaltransitions.com> wrote:

I've read the Tech Note 1 and explored a TIFF saved with Image Pyramid in PS CS6 with JHOVE and TiffUtil. I see no signs of the SubIFD tag anywhere in the TIFF I saved with Image Pyramid. Am I missing something?

Here is a link to that file: https://www.dropbox.com/s/ziwtxddcirwy4w6/1_120ASPH_f8_2900ppi_99eff-imagepyramid.tif

Based on Chris' comment that I should match the structure created when selecting Save Image Pyramid I must conclude we are "doing it right" as I see no sign of the SubIFD tag in such a file and only a NewSubFileType indicating they are reduced resolution versions of the primary. But based on Joris' comment we are doing it wrong and should make sure the resulting TIFF includes SubIFD references from the primary to the IFD with the reduced-resolution-of-primary.

Any further thoughts would be greatly appreciated. I know you've already been generous to reply at all.

On Thu, Jun 13, 2013 at 3:53 PM, Douglas Peterson < dep@digitaltransitions.com> wrote:

Joris and Chris: thank you both. I'll do just as you suggest as my next avenues of exploration.

Thanks for taking the time to reply!

On Thu, Jun 13, 2013 at 3:27 PM, Chris Cox <ccox@adobe.com> wrote:

Save a TIFF from Photoshop with the “Save Image Pyramid” checkbox enabled.

Look at the structure, and match it.

Also, see the SubIFD definition in TIFF Technote 1.

On 6/13/13 8:52 AM, "Douglas Peterson" <dep@digitaltransitions.com>

>> wrote:

> *Background About Me

> *I have put considerable effort into understanding the proper structure > for TIFFs. I've read an Intro to TIFF Creation <

> http://paulbourke.net/dataformats/tiff/> and the NewSubFileType <

> http://www.awaresystems.be/imaging/tiff/tifftags/newsubfiletype.html> > spec and learned to read hex (at an intro level). I have JHOVE and MAC OSX

TiffUtil at my disposal. I say all this not to brag (as I'm sure I'm one of the least knowledgable members of this mailing list) but only to explain that I have tried very hard to resolve this issue on my own before appealing for help from this community.

> *The Problem

> *Our company is having a problem with several software packages reading

our TIFFs as multi-page documents. That is, upon import/ingestion the software treats the two image IFDs in the TIFF as separate images that should both be imported.

Using JHOVE and TiffUtil I see our TIFFs create two IFDs (plus an EXIF

IFD which is presumably not important to this discussion). IFD#0 is the

primary image at full resolution. IFD#1 is a thumbnail of the primary image.

We want to continue to provide TIFFs with the IFD that contains a

>>> thumbnail as some users may have incorporated t