Colour Management in Lightroom
By David Harradine
After discovering how easy it is to import a bunch of images into Lightroom and prepare them for a variety of outputs, you could be forgiven for thinking that Lightroom does not use colour management at all. No working spaces to choose, no profile mismatches, or missing profile alerts to cause you grief.
But how do you think all those imported images look so good and manage to match their appearance in Photoshop, Bridge and other colour-managed applications?
As invaluable as colour management is for those who embrace it, it can be quite the pain for those who don’t, even, at times, generating hostility from certain circles wishing to maintain antiquated workflows. A hostility that unfortunately, for the hostile, only results in poor colour consistency across applications and devices.
So in Adobes desire to keep Lightroom as simple as possible to use they have made sure that the essential colour management procedures that must carried out are taken care of, as much as possible, behind the scenes. Meaning that colour management is alive and well in Lightroom, it’s just keeping it’s head down and getting the job done.
Colour Management on Importing
When importing images into Lightroom all existing colour profiles are preserved and respected. If you import images in to Lightroom without profiles sRGB will be the assumed colour space for generating the preview. In the case of Raw files, which do not have embedded profiles as such, Lightroom behaves exactly the same as camera raw, checking the metadata to see what model camera the raw file is from and applying the appropriate default camera profile.
If you have applied a custom profile in camera raw by way of the calibrate tab (discussed in the last issue of DR) then these settings will be both preserved and editable in Lightroom.
Colour Management whilst Editing
Technically Lightroom does not actually edit images, what it does is reference an existing file to generate a preview then allows you modify this preview via it’s image adjustment tools. However, these adjustments are not applied to the existing file, they are saved as metadata instructions to be applied to a copy of the file when you generate an export out of Lightroom.
This process is often referred to as non-destructive editing, because the original file remains unchanged and unharmed. So only when an export is generated does the notion of a working space come in to play. The space Lightroom uses to convert from the source space to the chosen output space is a rather un-conventional space that you probably don’t even need to know about to use the application to it’s full potential.
But let me tell you about it anyway. It’s a hybrid space created by Adobe and affectionately referred to as Melissa RGB. Melissa RGB has the wide gamut primaries of Pro Photo RGB and the tonal response curve of sRGB. These qualities have been deemed best suited to handle all conceivable colour variations that Lightroom may encounter and ensure the smoothest conversions regardless of what source space you have come from and what destination space you are heading to. But as I said, you didn’t really need to know that as it’s locked down and unchangeable.
Colour Management on Output
There are basically 3 output scenarios that you may encounter in Lightroom being;
1. Edit in Photoshop
2. Export images for use elsewhere or
3. Print directly from Lightroom to PDF, Web Gallery or your printer.
And this is where colour management rears its head for the first time. Just like processing a file through camera raw you have to choose an RGB space to process into and the usual suspects are here to choose from.
sRGB, Adobe 98 and Pro Photo RGB. The decision here depends largely on the intended usage of the exported file, with sRGB being best suited to the web as its relatively small colour gamut ensures greater consistency across a wide range of monitors. Adobe 98, the larger gamut space being ideal for most printing requirements and the super large Pro Photo RGB, being best suited to highly saturated images that are being printed on wide gamut devices.
Edit in Photoshop
If editing in Photoshop from Lightroom we have to choose an RGB colour space to render the Raw data into. This Photoshop edited RGB file will then be imported back in to Lightroom as a separate file from the original. Logically Jpeg is not an option here as the file is not finished so why apply lossy compression.
When exporting a file or files for use else where an RGB colour space also must be chosen. Your decision here is based on the intended use of the exported images.
When printing directly to your printer from Lightroom you can choose your printer profile and rendering intent from the colour management options in the print job tab. Note; only Perceptual and Relative are available, for more sophisticated output options such as cross rendered proofing you still need Photoshop.
Finally when exporting web galleries Lightroom will automatically convert all images to sRGB, so they will display perfectly in colour managed browsers like Safari and Firefox 3, and as well as they can in non colour managed browsers like all the others.
Needless to say, but I will, your monitor profile is also a key player in this sophisticated colour preview and conversion process. So regular calibration, profiling and verification is essential to ensure you are seeing the colours on screen as Lightroom is delivering them.
David Harradine is a photographer, trainer and Photoshop beta tester, who regularly runs training seminars throughout Australia and New Zealand on Photoshop, Digital Photography and Colour Management. More recently David has been running studio lighting workshops in Melbourne and photo tours to various locations.
For more on David’s current training events please visit http://www.whack.com.au/