Any way to pre-crop a raw file?

For an image file that is destined to be cropped, it would be an advantage in speeding up the Pure Raw process if the image could be “Pre-cropped”.

I can crop a Canon .CR3 file in Canon’s DPP program, but when I load it into the DXO Pure Raw interface, it is no longer cropped.

Any edits applied to your raw files in Canon’s proprietary DPP program are only viewable when using DPP. It writes the edits to a special area of the raw file which only it can read. Other raw processing software, including PureRAW, do not recognize any edits made directly to Canon raw files by DPP. Commercial software does not normally update raw files directly.


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RAW files can never be edited because they only contain data that wil be interpreted into pixels.

Joanna, Canon’s DPP is an exception to the rule. The edits are stored directly in its raw files and are ignored by other software.


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In what way is it an exception? As far as I know the raw data is only used to calculate the RGB raster image. Any further editing is done on that image.
When @Leigh crops a Canon RAW file, he is cropping that RGB raster image, not the RAW file. And when he loads that file in Pure Raw he is sending the RAW file to Pure Raw.


I think the confusion here is understanding how Canon’s Digital Processing Professional software stores it’s edits.

DPP is an exception because It does not use a database or sidecar files to store edits. Instead, It modifies Canon raw files and stores the edits in an area of the files not accessed by other software. There is actually a save feature in DPP to do that.

You can move a raw file edited in DPP to another copy of the program on another computer and when you open it you will still see all the edits. While DPP stores edits in its raw files, it does not modify the original raw data.

I was pointing out that Canon raw files are edited and updated by DPP. I did not mean to imply that the original raw data itself is modified


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I see. Nikon used to have a similar way to store the edits. But that doesn’t change the principle of how raw files are used. The edit list can be stored in a sidecar file or added as an attachment to the raw file. Just like keywords to mention another discussion. @Leigh is editing a RGB raster image but sending the raw file to Pure Raw.
Maybe I’m wrong but I’m wondering what the use is of Pure Raw outside PL. For further editing with the same bit depth as in a converter Pure Raw has to create a 16 bit TIFF file. But that has the disadvantage of working with huge file sizes and prevents some tools to use the RAW data as white balance and exposure compensation.


Like PhotoLab, PureRAW creates DNG files as its preferred output for additional processing which I believe are also 16 bit,


Edit an image and save the changes in DPP to get a file that is roughly twice the original file’s size…

Update: This is not the case in DPP4 any more. The the file gets bigger by about 100K.

The edit list is just a few Kb, just like the dop list. What is changing probably is the embedded jpg.
With Nikon there’s a jpg embedded to the raw file. In the day’s of CaptureNx2 that jpg was replaced by another jpg containing the edits and was of a much higher quality.


What would be nice is support for the cropping performed by Photo Mechanic. Photo Mechanic stores the data in XMP files which at least some versions of Lightroom and Photoshop read. Here’s what Photo Mechanic support have to stay about potential integration:

Yes, crop information in Photo Mechanic is written into metadata. By default, Photo Mechanic writes metadata to XMP sidecar files for RAW files, and for filetypes like JPEG, it is embedded in the image file itself. RAW editors like Lightroom and Photoshop will also read and write to XMP sidecar files by default.

If you are using RAW files, check your IPTC/XMP settings in Photo Mechanic’s Preferences by using the Command + comma keyboard shortcut to open Preferences, then use the dropdown menu or arrow buttons to navigate to IPTC/XMP.

By default, only "Always create and/or update XMP sidecar file’ is selected under “For TIFF-Based RAW photos”. Please see attached screenshot for reference.

If the "Add embedded metadata checkbox is selected, then Photo Mechanic is embedding the metadata into the RAW files. RAW software like Lightroom and Photoshop will need to be told to read and write from embedded metadata as well if this option is used.

Neat integrations like this which allow us to use our photographic tools better and improve our workflow are what float my boat. They also give the occasion to make a big announcement and catch the attention of the tens of thousands of pro photographers who use tools like Photo Mechanic and have already proven they will spend money on software which either improves their workflow or their work.

Reading XMP crop information wouldn’t even be all that much work. It’s a relatively straightforward proposition. Crop here and here, rotate this much. Of course whether to turn on lens correction or not will make a visible difference with some lenses but default lens correction and distortion settings are already easily handled by the existing Photolab preset system.

Of course DxO will ask that this feature be put up for voting where it won’t attract much attention: the Photo Mechanic users which DxO would do well to attract are outside the garden right now and would require an invitation to join the party.

What’s particularly elegant with this kind of enhancement is that it neither adds complexity nor even changes the existing interface.

PS. If DPP writes out crop information into an XMP or easily readable format, this support could be added as well. DPP (which I’ve used) is not really a tool many choose for triage alone (it’s a very good, if basic, RAW developer, with excellent colour rendition and lens correction but kind of slow and clunky) so DxO would be more on target to attract new Photolab users by adding support to pre-crop in dedicated triage tools, which do require a proper RAW processor coming by in a second pass.

Here’s Photo Mechanic’s assessment of the situation:

DXO Photolab will read star ratings and keywords from Photo Mechanic’s XMP file. It appears to write crop information to a proprietary sidecar file, a .dop file, which can be found using the Export Sidecar option.

Since Photolab already saves crop information in the sidecar file and already reads from XMP files, reading the standardised crop information which Photo Mechanic stores in the same XMP file should be an achievable goal. Of course, if a .dop file already exists for a file, then the XMP crop information could just be ignored. This keeps application logic simple and makes adding external crop as long as it matches XMP standard an easy and huge win.

Such a feature would help Photolab stand out among pro photographers who use tools like Photo Mechanic for triage. I’ll commit to buying another Photolab license if DxO implements read XMP crop in Photolab, compatible with Photo Mechanic, within the next four months.