ADV: Re: [DeepSkyStacker] #BugReport_v4 #DSS_64bit Loading output TIF in PixInsight v1.8

Richard Berry

Hi Michael--

The TIFF specification allows the creation of new tags. Tags can carry any type of information, and in this case it is not be needed to display the image correctly.


On 5/6/2018 12:36 PM, Michael A. Covington wrote:

I've been seeing that for some time and assumed it was benign -- DSS is including some kind of auxiliary information that PI doesn't recognize.  It didn't interfere with processing the picture.

Here is a list of TIFF tags, not including that one:

On 2018-05-06 13:49, Eelko Gielis via Groups.Io wrote:
Hi development team,

I just used version v4.1.1 64-bit DSS Live and ran into this message in PixInsight trying to open the AutoStack.TIF file.

** Warning: TIFF: Unknown field with tag 50008 (0xc358) encountered TIF file
I hope you can find anything to solve this issue. -Eelko.

Michael A. Covington, Ph.D.
Consultant, Covington Innovations, Athens, Georgia, USA


Please notice that Pixinsight posted only a "** Warning" message.  All that it is doing is notifying the user that there is a Tag that it didn't recognize - and therefore might not have made use of it (if the User had such expectation).

As Richard Berry pointed out, one of the significant benefits of the TIFF Format is that it is Extensible - both in big ways such as being able to utilize additional Bit Depths or Color Encodings and small ways such as additional User/Developer defined Tags.  (FITS format is very similar - it allows Users to define additional types of FITS Header Blocks with any sort of data from Geolocation to Ratings to additional Hubble Instrumentation data.)
I'm not sure whether DSS copies the TIFF Tags from Source to Results files, but it is possible that this TIFF Tag was written to the Source File by a previous Image Handling App or the Camera itself.