In Lightroom, as most of us know there are no color spaces to choose until you export an image. I’d like to demystify exactly what is going on in Lightroom and how it deals with color spaces.
First, lets talk about color spaces in general. A color space by definition is a description of a range of colors that can be represented. The smallest color space is CMYK used for off set presses used by most of the printing industry. The sRGB color space is a little larger and used for the internet and this is also what most monitors display. Adobe RGB is quite a bit larger and is the color space that should be used in most digital cameras to get the best image quality. Lastly, ProPhoto RGB is one of the largest color spaces around and can incorporate all of the colors captured by a digital camera.
Anyone who has used Photoshop quickly realizes that color management is a big deal. You need to set up your color settings dialog box in Photoshop so that you know what color mode you are in. With Lightroom Adobe wanted to simplify the color management process. Lightroom was created to have a ProPhoto RGB color space with an sRGB tone curve. We’ll get into what exactly that means in a moment. The reality is with Lightroom you are working up your images in a very large ProPhoto RGB color space. Exporting those images into an sRGB color space for example will lead to a certain amount of clipping in your histogram. Whether or not that clipping is important depends on the image.
Below is an image from a recent surfing shoot that I exported three different times into ProPhoto RGB, Adobe RGB and sRGB color spaces.
I went into Photoshop and took a screenshot of each histogram. Below are the histograms for the same image in ProPhoto RGB, Adobe RGB and sRGB color spaces and also the Lightroom histogram before exporting the image.
Original Lightroom Histogram (ProPhoto RGB)
Photoshop ProPhoto RGB
Photoshop Adobe RGB
Now as you can see the Lightroom histogram and the Photoshop ProPhoto RGB histogram are the same (as they should be - the Lightroom version is just stretched out a bit more than the Photoshop version). The Adobe RGB histogram has some clipping on the shadows side and since the ProPhoto RGB highlights had some headroom there is no clipping in the Adobe RGB highlights. Now the sRGB histogram has a big line on the left hand side showing significant clipping in the shadows and while there is no clipping in the highlights it is right up against the right side of the histogram. So, all this is to say that if you are not exporting into a ProPhoto RGB color space then you will most likely have some clipping in your exported images histogram.
Now, why would Adobe set up Lightroom to work with a ProPhoto RGB color space is the big question. The answer is ProPhoto RGB is the only color space that can contain all of the colors a digital SLR can produce. Most DSLR’s produce colors that are outside of the standard Adobe RGB color space even though you have your camera set to Adobe RGB. Hence for the highest image quality in a raw processor one would use the ProPhoto RGB color space. I highly recommend that folks use the ProPhoto RGB color space when exporting images out of Lightroom and as their archival color mode - then in Photoshop one can convert the color space to whatever is needed for output and have a lot more control.
Now, I understand that my methods may not be yours. Hopefully this isn’t super confusing. If you are shooting for the web and don’t want to have your shadows and highlights clipped then you have a few options - leave a little headroom on either side of your histogram and tweak the levels in Photoshop or use Adobe Camera Raw in Photoshop where you can set the color space and adjust the histogram while looking at the color space you intend to output the image into.
So, here I have just explained a little about how the color space set up in Lightroom affects the image when it is exported. While this topic might seem like a small detail it is very important to note when you are working up your images - because how you adjust the exposure, recovery, fill light and blacks sliders in Lightroom affects the histogram - and in turn affects the clipping that will occur when you export your images if you are not exporting into the ProPhoto RGB color space.
That’s it for this session. See you next week….
Adios, Michael Clark