Color Space Mismatches

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Today’s Question: I’m confused about the color space info I’m seeing. My Canon 5D recommends shooting in the sRGB color space. But my Preferences in Lightroom 5 under the External Editing Tab is set at ProPhoto RGB. After processing a photo in Lightroom, if I want to export the file I choose Color Space Adobe RGB. But here’s what I don’t understand: sRGB is supposed to be a more limited color space. So, if I’m capturing my original RAW image in the sRGB color space, how do Lightroom and Photoshop find those “missing” gradations that sRGB fails to capture? How can you produce a ProPhoto RGB file from a more limited sRGB file? Or is that sRGB choice is only for JPEGs and totally irrelevant because I shoot RAW? Can you clear this up for me?

Tim’s Quick Answer: The color space in your camera only applies to JPEG captures, not to raw captures. Within Lightroom you aren’t able to change the color space. When you send a photo to Photoshop or another application, or when you export a copy of an image, you can choose which color space you want to use. In this context I recommend using ProPhoto RGB if you will be exporting a 16-bit per channel image for extensive editing. For photos that will be printed the Adobe RGB color space is generally a good choice. The sRGB color space should be used for images that will be shared digitally, such as online.

More Detail: The color space for an image defines the specific range of colors that are available. As a very simple example, a Grayscale color space would contain only shades of gray, while an RGB color space could contain all of the colors of the rainbow.

When processing photos, it is generally advantageous to have the largest range of colors available, to provide greater flexibility for editing and smoother gradations of tone and color in the final image.

For raw captures, the color space in the camera does not alter the actual pixel data. Only JPEG captures would be affected by the in-camera color space.

The ProPhoto RGB color space is the largest among the standard color spaces. However, because it is so large it should only be used for images with a 16-bit per channel (or higher) bit depth. For 8-bit per channel images (such as JPEG images), one of the other color spaces should be selected. If you are sending a photo to Photoshop for extensive editing, for example, you may want to use the ProPhoto RGB color space.

For images you intend to print, the Adobe RGB color space is also a good choice. The Adobe RGB color space is appropriate for 8-bit or 16-bit per channel images. So, for example, if you were sending an image to Photoshop to prepare it for printing, you could use the Adobe RGB color space.

The sRGB color space is the smallest, but it is also closest to the typical color space for a computer monitor display. This is one of the reasons it is a good choice for images that will be shared digitally, such as online or in a digital slideshow. For these types of output, the sRGB color space is a good option.

So, for raw captures the image itself will not be affected by the in-camera color space. In Lightroom you don’t have the option to change the color space for editing photos. However, you can choose a color space when sending a photo to an external editor or exporting a copy of an image.

To learn more about color management in the context of photography, take a look at my “Color Management for Photographers” course on the GreyLearning website here:

https://www.greylearning.com/courses/color