Cropping: what does these fields mean?

[sinus]

Hi
In the Metadata "XMP cropping" we have these fields, like in the attachement.

What do these fields mean:

- Cropped (what if I uncheck this)?
- Already Applied
- Crop Unit (should there be a value)?

These questions are for my understanding of these fields, nothing else. 

Thanks in advance.


[attachment deleted by admin]

[Mario]

Did you lookup the corresponding info in the help?
Just search for Crop in the help index. In the Metadata 2 topic press Ctrl+F and search for crop to find the corresponding options. This also includes a description about what XMP crop records are, which applications create them, what IMatch can do with them, what happens when you set the crop record to not enabled, why there is no unit etc.

[sinus]

Did you lookup the corresponding info in the help?
Just search for Crop in the help index. In the Metadata 2 topic press Ctrl+F and search for crop to find the corresponding options. This also includes a description about what XMP crop records are, which applications create them, what IMatch can do with them, what happens when you set the crop record to not enabled, why there is no unit etc.

Yes, I did look of course.
I found some information about cropping.
What I understand and know.

But I was interested into these fields, and there is nothing, what I can find about them, specially the field "Already Applied" I do not understand.

But ok, finally it is not so important, the fields are there, that is it ... somtimes too much knowledge is not necessary (and I mean this really) 

[Mario]

There is some documentation about this in the Metadata Working Group standard:

http://www.metadataworkinggroup.org/specs/

The "Already applied" tag as delivered by ExifTool is not part of the XMP standard or the Metadata Working Group specification as far as I can tell. It think is written by some Adobe applications (maybe some other applications as well). I guess the idea is to record that the crop record has already been applied to the image - e.g., while exporting a RAW file which has been cropped in LR/PS into a DNG or JPEG file.

There is also the "Enabled" tag, which is supposed to be set when the crop record is "active" and should be applied. Unfortunately, Adobe  keeps the crop record in XMP data (and enabled set to true) even when they export a file into JPEG/TIFF and apply the crop at that time. This means that the JPEG/TIFF image whatever is already cropped, but still contains a valid and enabled (!) crop record.

It seems that Adobe applications ignores this and uses probably some other data they keep somewhere in their undocumented XMP data to tell if they need to apply the crop record or not when opening the resulting file. Nothing of this is documented.

Other applications, like IMatch, which try to do the right thing and apply the crop record if valid and set to enabled, cause the image to be cropped twice. This is why you can disable support for cropping in IMatch (it's off by default when I recall it correctly).

BUT, if you crop your RAW files in LR/ACR and you want them to look correct in IMatch, you will have to enable this. If you then look at JPEG or other image files created in an Adobe product you may get wrong results, though. Unless Adobe either strips the crop record or marks it as disabled.

IMatch looks at the "Already Applied" tag and if it exists and is true, it does not apply the crop record even when you enable the "use crop" option. IMatch assumes that if this is set, the crop has already been applied to the image data, even when the file has a valid crop record which is marked as "enabled".

[sinus]

Thanks, Mario, for your long answers. That is more than enough that I wanted to know. Great, thanks.