Not semantics at all but a correction​ of inaccurate and misleading statements. I knew exactly what you meant, but my point was that the raw files do get physically edited and updated which is an important distinction since so many people have stated categorically that they do not. And others have also used the sidecar term with regard to DPP which is inappropriate and misleading. The data is imbedded in the raw file and is not a sidecar, a term not used by Canon, and which implies a seperate file. I'm trying to prevent the confusion that this misinformation will cause. Many people will not read between the lines after reading this thread and will assume that (a) raw files cannot be edited and updated under any circumstances, and (b) that DPP uses sidecars to store edits. They will then pass these errors on to others, regardless of the fact that both premises are incorrect.

Sometimes we use shorthand terminology to express a concept which others in the know will understand even though the way its expressed may be strictly speaking inaccurate or incomplete. Using shorthand is fine when there is an even playing field, but when people without that specialized knowledge are added to the mix, confusion reigns.

Raw files CANNOT be edited. When you open one, the software does one of two things:

• It displays a thumbnail JPEG that was created by the camera and stuffed into the raw file

OR

• It displays a BITMAP converted from the raw data, using the EXIF data that was created by the camera based on menu settings (and stuffed into the JPEG preview).

DPP is great, because it takes the second approach. It shows you the same conversion the camera would have made (or made) for an in-camera saved JPEG. BUT, and here's the important part, you can edit it in DPP any way you like, and save a different kind of file, or send it to an external editor such as Photoshop for further editing. AND, even better, the conversion can be saved in 16-bit form, which preserves as much of the camera's 12- or 14-bit color depth as possible.

When you edit a raw file in DPP, you are working with the raw data, and the software is showing you an 8-bit or 10-bit conversion, depending upon your monitor's and graphic processor card's capabilities. There is no part of this process that refers to the original JPEG once the file is open fully. The original JPEG is a thumbnail used by operating systems (Windows Explorer and Mac Finder) to display a preview.

I haven't used DPP in a while, but on the versions I used, you had a menu selection to revert back to the in-camera default settings. As you work with raw files, you can only export them. You cannot "re-save" a raw file. When you leave DPP, the changes you made ARE STORED — but as sidecar data. They are thrown away if you revert to the in-camera default settings.

Most camera manufacturers' software works in a similar manner. Third party editors usually display raw files using their OWN set of default conversion parameters, although some will offer an option to use the "as shot" data.

While there is good reason to save redundant copies of files (as insurance against hard drive crash or storage media failure), You should always be able to revert to a view of the file as it would have looked as a JPEG, because the EXIF data is still unaltered and can be used for a new view of the file.

Okay, this is all words without any concept of what is actually being done.

The raw sensor data in the RAW file is not changed. It is not edited.

But it is only used in one way: it is read into memory from that file and fed directly to the demosaicing algorithm which is known as a converter. The output from the converter is typically a 16-bit depth RGB (three channel color) bitmap data set. The converted data set has very significantly been changed and has no direct relationship to the raw sensor data. In fact it is impossible to then convert or in anyway recreate the original raw data set using the RGB bitmap data. The conversion is a one way process.

Everything from that point is done with the bitmap and nothing else is done with the raw sensor data. The raw sensor data set that was read into memory is simply discarded, normally serially discarded with each new chunk that is read because the entire data set is never needed to be all there at once for a typical large RAW file.

Any bitmap that is exported to an image file format is done so with the intent that if the file is read back into memory a new bitmap that is identical to the original will be created in memory. With a "lossless" format it actually will be bit for bit identical. With a "lossy" format it will merely be close (very close for high quality and not so much.for lower quality).

Not entirely correct with respect to the Canon DPP program which the OP is using. When edits are made to raw files in DPP they are stored within the raw file itself and the last modification date of the file is updated. There are no sidecars or databases entries. However, these changes can only be viewed in DPP. Other software like Lightroom will display the original data only and ignore the changes. Within DPP, the raw image can be restored to its as shot condition at anytime but the original file modify date is not restored.