Photoshop Elements >

Raw File Processing > 2

As mentioned, when you process a raw file, the file itself is not changed.

The processing instructions are stored as metadata.

The metadata is stored in one of three ways.

A database file is created and is saved to your computer.

This method has a drawback.

The metadata file doesn't accompany the raw file should you move the raw file elsewhere, such as to a flash drive or external hard drive.

The database is located in Users > User Name > AppData > Local > Adobe > CameraRaw > Cache.

An Extensible Metadata Platform (XMP) file is created.

This side-car file accompanies the raw file should you move the raw file.

If you want to revert to the unprocessed version of a raw file, delete the xmp file for the raw file.

If the raw file is a DNG raw file, the metadata is saved as part of the DNG file.

By default, Photoshop Elements uses the second method.

You can use the first method by going to Preferences at the top of the screen.

If you're using other software, check in the software's preferences section for the method being used, and to change the method if desired.

Color interpolation, or demosaicing, is done automatically when you open a raw file.

A complex interpolation algorithm determines the color of each pixel.

Most chips (Not the Fovean chip) are B&W chips, so to speak.

Each photosite has a red, green, or blue filter.

The filters are arranged as a Bayer Matrix (or Bayer Filter Array) across the sensor.

There are twice as many green filters.

This is because we see more green than red or blue.

So, while there are colored filters, no actual color is recorded.

Instead, the interpolation algorithm compares the brightness levels of adjacent photosites, and determines the color.

Below, we'll use the Adobe Camera Raw converter in Photoshop Elements.

The version of Adobe Camera Raw in Photoshop has more commands than the version in Photoshop Elements.