Saving jpeg images with metadata intact

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jsachs
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Re: Saving jpeg images with metadata intact

Post by jsachs »

A number of the metadata fields such as Rating and Title that you are reporting as missing are actually Microsoft-specific properties not stored in the file metadata and for which there is no corresponding tag. Where exactly this information is stored appears to be something of a mystery as I have seen conflicting information about this posted on the web.

I have noticed that when I try to copy a file, I sometimes get a warning that some of the file's properties will be lost, and I suspect this is related.

If anyone has a file where the Maker Note or IPTC data is being dropped, I would like to get a copy of the file to work with as both of these should be embedded in the EXIF data.
Jonathan Sachs
Digital Light & Color
Winfried
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Re: Saving jpeg images with metadata intact

Post by Winfried »

Which IPTC data do you mean?
The old (outdated) IPTC-IIM or the XMP-based IPTC-Core data?
Exif is not IPTC, although some field exist in more than one type of metadata.
Please have a look at http://www.photometadata.org/META-101-metadata-types
Maybe this illustrates my view on metadata.
Winfried
-----
migrated to Windows 10 in Nov. 2019
PWP Pro 64
CUDA not available
Bob Walker
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Re: Saving jpeg images with metadata intact

Post by Bob Walker »

Jonathan,

OK, I am getting pretty discouraged. Yes, I picked a few elements of metadata that are handled by Windows so the issue could be easily replicated.

The "Tags" that show in a windows explorer window are stored in the IFD0 block of the EXIF metadata under the name "XPKeywords", according to exiftool (and EXIFToolGUI). What confuses me is that for some images, PWP 7 acts differently than PWP 8 (no big surprise, that's OK). But PWP7 passes through some of these tags, PWP 8 does not. PWP7 mangles camera shooting stuff like focal length, and camera lens model, etc, but PWP 8 does not. All these conclusions are based on a very small sample of experiments.

A lot of this information is replicated as an imbedded XMP file or as IPTC metadata. I don't think it makes sense for PWP to become a metadata editor, but I wish I could discover a good way to add metadata to an image and have it respected through various transformations. An external .xmp sidecar file is probably best, but I haven't found a metadata editor that generates a "complete" sidecar file.

exiftool seems to be about as complete as they come, but I am too lazy to learn how to use it in a batch mode on multiple images all at once.

I guess I give up, let's not worry about this any more.

Bob
jsachs
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Re: Saving jpeg images with metadata intact

Post by jsachs »

The EXIF standard (http://www.cipa.jp/std/documents/e/DC-008-2012_E.pdf) does not mention the Microsoft tags at all.

There is an EXIF tag for IPTC data which is encoded as a single block of data. PWP should be saving this block and writing it back out when the file is saved, along with the other EXIF data.

Unfortunately, I need to use external libraries to read and write JPEG and TIFF files as it is a major undertaking to write code to support these formats. PWP 8 uses Microsoft's WIC (Windows Imaging Component) to read and write JPEG and TIFF files and so PWP is one level removed from the actual metadata since it relies on the libraries to decode/encode it and pass it through. PWP 7 used different libraries, so it is not surprising that it does not work exactly the same. The WIC libraries do not seem to pass through XPKeywords data which is why this may be getting lost. I can look into this later when I have time.

Sidecar files are a disaster since they can easily get separated from the original file, or left behind when the file is renamed or deleted. And they clutter up the disk and then each application creates their own sidecar files leading to a giant mess.

Depending on metadata being replicated perfectly when passed from application to application is probably not a good strategy.

If you have specific tags such as IPTC or MakerNote that are getting lost, I should be able to track down what is happening if I have some sample files. If you just tell me it doesn't work, there is nothing I can do.
Jonathan Sachs
Digital Light & Color
Winfried
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Joined: June 18th, 2010, 4:27 pm
What is the make/model of your primary camera?: Pentax K1

Re: Saving jpeg images with metadata intact

Post by Winfried »

Jonathan,

I just send you some images (ooc and modified with added metadata, before and after saving the files with PWP8).

@Bob
I support " I don't think it makes sense for PWP to become a metadata editor".
I use IMatch as my metadata editor. The "problem" is that IMatch and other tools too use the xmp based IPTC-Core standard and no longer the outdated IPTC-IIM. External .xmp-files won't solve the problem, because it is part of the definiton of xmp to include xmp-metadata into the files if it is possible, i.e. for *.jpg, *.tif, *.psd, and even for *.dng.
For *.dng it is a backup disaster: adding one keyword (some bytes) results a backup of the whole rawfile.
Winfried
-----
migrated to Windows 10 in Nov. 2019
PWP Pro 64
CUDA not available
Bob Walker
Posts: 78
Joined: April 25th, 2009, 9:08 am
What is the make/model of your primary camera?: Canon R5
Location: Los Alamos, New Mexico
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Re: Saving jpeg images with metadata intact

Post by Bob Walker »

Jonathan,

The XPKeywords (a Microsoft invention) are replicated in the IPTC data "Keyword". No IPTC data is replicated from PWP8 using either a "Save as" or "Export" file-writing dialog. Without IPTC being copied, and no Microsoft XPKeywords, all keywords are lost.

Off topic perhaps, but BreezeBrowser will read EXIF/IPTC metadata from one file and write it into another one, so I can recover the metadata after exporting by using that software. Painful, one file at a time. So that's my workaround.

Bob
den
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Re: Saving jpeg images with metadata intact

Post by den »

...
Bob...

I routinely batch process the following EXIF tags using ExifToolGUI to multiple image files [CR2, JPEG, and TIFF] contained in a folder:

-LensType#=234 -Exif:LensModel="Canon EF-S 17-85mm f4-5.6 IS USM" -Exif:LensInfo="17 85 4.0 5.6" -Exif:Artist="...den..." -d %Y -Exif:Copyright<"(c) $Exif:DateTimeOriginal IMAGEs by DEN" -Exif:ImageDescription="-"
ExifToolGUI and Part 3a Command Line Option set.jpg
ExifToolGUI and Part 3a Command Line Option set.jpg (82.34 KiB) Viewed 3317 times
Perhaps you could do something similar with the tags of particular interest to you.

There is a dated 2013 pdf [750 KB] describing what I do if of interest that I could upload to my website for your download.

...den...
jsachs
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Re: Saving jpeg images with metadata intact

Post by jsachs »

It looks like there is a mechanism for reading and writing both IPTC and XMP metadata using the WIC library I am using to read and write JPEG and TIFF, so there is hope for supporting these going forward. I will take a deeper look at this at some point when I have more time.
Jonathan Sachs
Digital Light & Color
Bob Walker
Posts: 78
Joined: April 25th, 2009, 9:08 am
What is the make/model of your primary camera?: Canon R5
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Re: Saving jpeg images with metadata intact

Post by Bob Walker »

den,

Thanks. I realize that exiftool is the software that is under the hood for many of the metadata editors around, so I probably need to learn the syntax, I have just been lazy. exiftool for photos reminds me of ffmpeg for videos -- it's to go-to software for its purpose, just a steep learning curve for all the syntax and options.

I just started looking at ExifToolGUI again, had been concerned that it isn't being supported, but maybe that's not an issue. Thanks for the recommendation.

Jonathan,

Thanks for putting this issue on the burner (even if a back burner). I really meant it that you shouldn't spend a lot of time worrying about it, in comparison to the value of your other work.

Bob W
jsachs
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Joined: January 22nd, 2009, 11:03 pm

Re: Saving jpeg images with metadata intact

Post by jsachs »

I place a high value on preserving metadata in image files where possible, so I would definitely like to fix this at some point. Right now I am focusing mostly on documentation so I can get to beta and invite new users to try the software.
Jonathan Sachs
Digital Light & Color
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