What does Lightroom’s Camera Calibration/Profile setting actually change, and when should you choose it?
Asked 8/23/2014
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In Lightroom/Adobe Camera Raw, changing the Camera Calibration/Profile clearly affects more than just a simple color label: it can alter color rendering, tone, the histogram, and even the baseline brightness of a RAW conversion. What is Adobe actually changing under the hood when a different camera profile is selected? Is it mainly a RAW-to-color-space mapping, or can it also include tone and exposure adjustments? Also, from a practical workflow standpoint, is this something that should usually be chosen at the start of editing, or is it safe to change later in the process?
Originally by Photography Stack Exchange contributor. Source · Licensed CC BY-SA 4.0
Photography Stack Exchange contributor
11y ago
2 Answers
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A camera profile may consist of several operators, including:
A linear transform (a matrix) from the camera RAW color space to CIE XYZ color space (used to compute the conversion transform to ProPhoto RGB, which is the working color space of Lightroom).
An HSV lookup table - Similar to the HSL function in Lightroom, but provides much more control on the transform.
Exposure baseline - can offset the baseline exposure (effectively it moves the 'zero' point of the exposure slider).
A "Look" table - Another HSV lookup table, to apply a custom look, on top of the "correct" colors.
A baseline tone curve - An RGB tone curve, usually brighten the image significantly.
Steps 1-3 should bring the image to the "correct" colors, while steps 4 and 5 aim to produce pleasing colors/tones (this enables to mimic the "as shot", a film-like, or other look that people may consider "better" for their purpose).
Adobe hides these baseline functions in the camera calibration, because they represent a starting point for the user edits. Also, most of them are too technical for the average user, or may even impractical to fine-tune by hand (e.g. large HSV lookup tables).
Originally by user13437. Source · Licensed CC BY-SA 4.0
user13437
11y ago
0
Generated from our catalog & community — verify before relying on it.
Lightroom camera profiles are part of the RAW conversion itself, not just a cosmetic adjustment. Based on the answers, a profile can include:
- a transform from the camera’s RAW color space to a standard color space
- lookup tables that adjust hue/saturation/value
- a baseline exposure offset
- a “look” table for a preferred rendering
- a baseline tone curve
So yes: changing profile can affect color, tone, histogram, and apparent brightness, not just color accuracy.
A profile is always applied before other edits. If you switch profiles later, Lightroom effectively re-renders the RAW file with the new profile and then reapplies your existing adjustments. That’s why it can feel like the whole image shifts.
In practice, profiles serve two purposes: more “correct” color and more “pleasing” color. Some are meant to match camera-maker picture styles; others aim for Adobe’s preferred rendering.
Workflow-wise, it’s usually best to choose the profile early, because later edits may need refinement if the profile changes the image significantly. But it is safe to change later if you want to compare renderings—the edits are non-destructive and reapplied automatically.
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