LAB colour space

[HansS]

Is there a problem viewing photo's in LAB colour space?

[HansS]

The problem seems to be related to the colour space. The protected files collection is empty.
A number of files have no thumbnail and on double-click I get the This file cannot be displayed message.
Irfanview has no problems with these files. The files I checked are all in LAB colour space.

[Mario]

Please provide more info.

You did not even say which file format you are processing.
Or what operation you tried to perform. "Viewing" can mean many things.

What has the "protected files" collection to do with it? This collection contains all files for which you have set the protection option. Did you do that?

Always include a log file (see log file) when you report a problem. This will tells us more.
Repeat your test / workflow and then attach a ZIPped version of the log file from that IMatch session.

There is no general problem with the rarely used l*a*b color space.
Also include a sample image which causes the behavior .

[HansS]

Thank you Mario, for your fast reply.

Please don't forget I am still trying to find my way in IMatch.
The files are imported with the Lightroom importer app.
While looking for the best way to leave LR, I have converted a number of edited raw files to tiff files. In some of those the lab colourspace is used.
In the file panel these files originally didn't show a thumbnail but the Irfanview logo.
(Browsing the help pages, the first explanation I found was about protected images. There was one file in the Protected collection.  In the meantime I removed it, it probably got there by mistake. And yes now I understand protection is not relevant to the matter under discussion.)
I replaced some 'lab' tif files by 'profoto RGB' tif files and after a refresh the thumbnails were there.
Even more baffling to a just starting IMatch user: after reverting  those 'profoto RGB' tif back to 'lab' tif and refresh, the thumbnails are still there. Double clicking those 'lab' tif files, they show up in the default viewer (if that is the right term) showing the colour workspace as CIELAB D50.

I think I could use profoto RGB in future altough there is a small penalty in filesize, but I would like to know what is happening.

Attached is the first CIELAB D50 file that made it full circle. (Sorry the file could not be sent size 171Mb)
I would prefer to postpone the repeat of the workflow to a more convenient time.
Thanks, Hans

[Mario]

The color space has no impact on the size of the files, at least as far as I'm aware of. Do you use ZIP or LZW compression for your TIFF files? Uncompressed TIF files are of course very large.

If IMatch shows an application icon instead of a thumbnail preview, the file format is unsupported. IMatch then displays the icon of the application associated with the file format. It seems you have associated IrfanView with TIFF files.

IMatch being unable to handle TIFF files is uncommon. Although TIFF is just a container format and can hold dozens of different flavors of image formats, IMatch uses the official TIFF reference implementation fo image processing and that should handle all properly formatted TIFF files. The implementation may not cover all esoteric or rarely used flavors, though. But I don't recall problem reports from other users, and TIFF is a format used by many institutional and commercial users for long-term archival. But they all probably stick to standard TIFF variants, for good reasons.

As I said, without a sample TIFF file or at least a log file, I cannot tell more.
I see no attachment in your post. The post limit is 2 MB and TIFF is not accepted. Just create a small TIFF file and then ZIP and attach it. I will look into it next year.

Or you send me a sample image to my support email address email.
Please include a link back to this community thread in your email. I get many emails per day and a link will help to know what's what.

If IMatch cannot read the format, it will use a Windows service to produce a thumbnail. If Windows is also unable to produce a thumbnail, IMatch falls back to display the application icon. But for TIFF this would be very uncommon. Both IMatch and Windows being unable to produce a rendition...do you perhaps have a TIFF WIC codec installed?

You can check by selecting one of the problem TIFF files and then go to Help menu in IMatch > Support > WIC diagnostics. Save the output to a text file and attach to your reply.

[HansS]

Thank you again for taking the trouble to answer.

I doubt if the subject warrants further study. I will not save tif's with CIELAB D50 colourspace, because of limited support by photo editing software..
But I still wonder why a 'lab' tif file that replaced a 'profoto' tif file has a thumbnail and is shown in the viewer in IMatch, contrary to the original 'lab' tif file.

Attachments:
1. There seems to be no WIC codec on my desktop for 'lab'tif files.
2. The WIC info on the 'profoto' tif
3. The WIC info on the 'profoto' tif replaced  by 'lab'tif.
4. The  'lab' tif that replaced the 'profoto' tif in the viewer.

5. The 'lab' tif will be sent by email
6. The 'profoto' tif will be sent by email

The files were exported with Affinity Photo, with the preset either TIFF LAB 16-bit or RGB 16-bit. The original document at the time of export was in the profoto colourspace.

If you think a log could be helpfull I could repeat this sequence, but preferaby in 2019.

Have a happy christmas and a good start in the new year.

Hans

[Mario]

I used ProPhoto color space files in the past often, never had issues as far as I recall.
But I have never used Affintiy Photo for creating TIFF files. Only pro tools like Phtooshop or scanner software.
Maybe Affinity Photo produces 'special' TIFF files. I have a license for Photo but I'm not using it very often. Affinity Designer is great, Photo not so much (at least for my line of work and retouching).

I will look into your file next year.
Make sure you include a link back to this thread in all emails. I handle about 30 to 50 emails per day... 

[HansS]

I think when a picture is replaced by an unsupported format IMatch refreshes the data, but leaves the old picture in place.
Once again I saved a file in the PROFOTO colourspace, and then replaced it after editing the text in the picture in the CIELAB D50 colourspace.

Attached are:

• Screenshot of the 'PROFOTO' file in the viewer
• Screenshot of the 'CIELAB D50' file in the viewer
• A jpg version of the 'CIELAB D50' photo

Personally I would have preferred no picture or a warning when replacing a file in an unsupported format.

As a rule I will not save pictures in the lab colourspace, but for color corrections and sharpening it is a useful tool.

Thanks again for your great support.

Hans

[Mario]

I don't understand. When a file is modified externally, IMatch will rescan it. Including the thumbnail and the cache image (if one exists).

I don't know if the obscure case that an image already in the database is replaced by an application which an image that is not supported by any of the image libraries (also rare) retains its thumbnail and cache image. I have never tested that and don'r recall a support case.

As I said above, always include a log file from the session where you experienced the problem. Else we can only guess at what might have happened and that's usually useless.
Screen shots explain only very little.

For information about the IMatch log file, how to create one, the debug mode etc, please see log file.

[Mario]

I have tested the files you have sent me via email.

None of the files is recognized as a valid TIFF by any of the imaging libraries IMatch uses and neither by the standard Windows TIFF WIC codec.
These TIFF files seem to be very special and IMatch cannot support them. Not even Windows Explorer or PhotoViewer handles them.

When I open them in Photoshop CC and save them as TIFF in one of the standard (non-Lab) color spaces , IMatch can read the file without problems, Explorer too, PhotoViewer and my other imaging applications.
I recommend using a standard color space if you want to view previews of your files in IMatch and other applications.

[HansS]

I apologize, the middle photo should have been in the profoto colourspace. By mistake I sent a copy in 'lab' space. I assume you saw that when opening the file in PS.

Lets go back what this is about.
I am looking for an alternative to the library functions of Lightroom CC.
While testing IMatch, I noticed that a picture in a file type that was handled without problem by the Adobe photo products was not shown in IMatch.
No problem for me, I can live without thumbnail, should I feel like saving a partly processed photo in this particular format.
(As an aside I remarked that a situation could occur that an image was shown in IMatch, that was out of sync with the metadata in IMatch. In the time I worked as a systems developer that would be seen as a bug.)
Your last post in referring to PS CC, could be seen as a suggestion to stay with the 'professional' Adobe software.

Nonetheless I see IMatch as a good flexible dam for photos, even if archiving in a not output oriented format is not (fully) supported.

Hans

[Mario]

IMatch does currently not support the lab color space for TIFF files. I don't know any library or toolkit which does. Except maybe the LeadTools Pro SDK, but this costs several thousand dollars per year plus royalties for every copy of IMatch sold. I doubt that there are enough users in the IMatch user base which use the rather exotic color space lab for image storage. Lab is good for certain image operations (sharpening comes to mind) but not really as a long-term archival format.