efg's Research Notes

 


TiffTags Utility
 

Earl F Glynn
Stowers Institute for Medical Research
30 June 2005

 


Download (available under GNU General Public License): 
Windows Executable  |  Delphi Source Code
(with ZeissToSGI utility)


GretagMacbeth Multi-Image Example File

 

Also see:  ZeissToSGI Utility


Purpose
The purpose of the TiffTags utility is to display the "tag" fields in a TIFF (tagged image file format) file.  For a limited subset of TIFF files, the program will display the image.

The program is intended as a "laboratory" for researching problems with TIFF files using the Delphi language in Windows.  Only "tags" of interest have been implemented.

Background
While Tagged Image File Format (TIFF) images are common, there can be many problems using TIFF files, especially created on a variety of scientific devices. These TIFF problems resulted in some suggesting in jest that TIFF really stands for "Thousands of Incompatible File Formats."

Adobe TIFF Support Knowledgebase:  "The level of technical knowledge required for one company to support the current TIFF specification is prohibitively high."  

Adobe "owns" TIFF (they own the copyright on the TIFF specification and own the TIFF trademark), yet Adobe's own Graphics Server "does not support all the types of TIFF files."

Adobe provides the Aldus TIFF Specification (Revision 6.0, June 3, 1992), which describes the "normal" tags used in the files.

Other TIFF resources:

TIFF Tag Reference, Baseline TIFF Tags

LibTIFF -- TIFF Library and Utilities

The TIFF Image File Format

ICC (International Color Consortium) Profile Tagging Specifications

The Unofficial TIFF Home Page

Free Online Dictionary of Computing"The incompatibility of extensions has led some to expand 'TIFF' as 'Thousands of Incompatible File Formats'."

Some vendors create files for use with scientific equipment that are really TIFF files.  For example, the Molecular DynamicsGEL Image file format is a TIFF file with some added tags. (Molecular Dynamics was purchased by Amersham and then purchased by General Electric, so it's not clear where.)   The GEL Image File Format contains 10 "private" TIFF tags, which were registered by Molecular Dynamics with the Aldus Corp. (now Adobe). 

Software Requirements
Tested only using Windows 2000, but should work on other versions of Windows.

Download the executable and test images to any convenient directory.  No special installation is required.

Step-by-Step Procedure
1.  Click on the TiffTags.exe to start the program. 

2.  On the Tags tabsheet, press the Read Tags button, select a TIFF file (or other files, such as GEL files), and press Open.

3.  You can now inspect the TIFF tags in the file, however, you may need the TIFF specification to make sense of many of the values.  

The Tag and Offset columns are in hex to simplify following a hex dump of the file.  The items in the "Value" column are generally in decimal, and when there is an array of values only the first few are shown.

The spinbox at the left is present when a TIFF file contains more than one image.  Use the spinbox to select the tags for each image in the file.

For example, the full-resolution TIFF files created by a Nikon CoolPix 990 has two images in its TIFF file.  One is the full-resolution picture, and the second is a thumbnail:

 

4.  For certain kinds of TIFFs, the image can be viewed on the Image tabsheet -- only attempt to view a TIFF image after exploring it's tags.  Once the tags have been read, press the Read Image button to display the image.

 

5. Press the Sequence button at the lower left to see each image in a multi-image TIFF file for specified number of milliseconds.

 

 

6.  Certain options are available only with 16-bit images.  These options should be selected before pressing the Read Image button.

 

If desired, you can shift the bits in each 16-bit quantity to the right by a specified number of bits.  The SQRT (square root) transformation takes the square root of a 16-bit value with a result that is guaranteed to fit in 8-bits.  The False Color option isn't very fancy, but allows to see some detail in the image.

 

7.  The tags in some TIFF-like files, e.g., GEL files, can be studied using the TiffTags program:

 

 

Discussion

Having such a broad standard, like TIFF, that no one can follow completely makes file portability quite difficult in some cases.


Updated
30 June 2005