One of the quiet traps in digital photography is the assumption that the colour profile applied in post-processing is a neutral starting point. We tend to think of white balance as the colour decision, and the profile as something closer to a technical default. In practice, that is not quite true.
I was reminded of this while processing a photograph of two London Air Ambulance helicopters on the ground at RAF Northolt. The image shown above was made at night on my Sony A1, with the helicopters illuminated only by the airfield lights. I assume those lights are LEDs, but I don't know their spectrum. The white balance, taken in Lightroom from a ColorChecker Passport shot under the same lighting, came out at 4650K.
That gave me a useful opportunity to compare a few different starting points. I made a Lightroom colour profile from the ColorChecker image taken under the Northolt lights, and then compared it with Adobe Color, Camera ST, Tony Kuyper’s linear profile with an added curve, and two Cobalt profiles (one with an added curve).
The custom Northolt profile looked most convincing to me. The helicopter red looked like red, not orange-red. The coloured markings on the tail had good separation, and the concrete apron still looked plausibly lit by artificial light without becoming unpleasant. Importantly, it also matched my memory of the scene. I don't place too much weight on my memory :), especially under unusual lighting, but it was reassuring.
Adobe Colour was the surprise, although perhaps it should not have been. It rendered the helicopter distinctly too orange and rather less saturated. Camera ST, which I used for some time as a starting point for Sony and Nikon, because it is intended to resemble the camera output, was only slightly better. In both cases, the files could be pushed closer using Lightroom’s Calibration and Colour Mixer panels, but that felt like fighting the file rather than editing it.
The linear profile was interesting. With a curve added, the tonal response was much better, but the colour still tended towards orange. A linear profile is primarily about tone. It does not magically solve the colour-transform problem created by a difficult light source, a particular sensor, and a very saturated painted subject.
The Cobalt profiles were the most useful general alternatives. Cobalt Flat, with a simple curve added, produced a very clean and controllable result. Cobalt Colours was also strong: not identical to the custom Northolt profile, but close enough that, without the direct comparison, I doubt I would have questioned it.
My aim here was not laboratory colour accuracy. Under LED airfield lights, with glossy paint, reflective markings, glazing and specular highlights, too many variables remain for that. A ColorChecker profile is a good anchor, but probably not the absolute truth. My more practical test is this: would someone who knows the London Air Ambulance livery look at the image and feel that something was wrong?
With Adobe Color, I think the answer is probably yes. With the custom Northolt profile and the Cobalt profiles, I doubt they would.
I think there is a general lesson here for the way I work. White balance can make the greys look right, while the reds and greens are still wrong. The profile is not a passive default; it is an active rendering decision. When I can make a specific ColorChecker profile under the light in question, I'll certainly do that. When I cannot, I want a profile that gives me a believable starting point and does not immediately push important colours in the wrong direction.
That is why, for my own work, I am increasingly wary of treating Adobe Color as the automatic starting point. My general view for some time has been that Adobe Color obeys the 80:20 rule: that is to say, it is OK for 80% of people, 80% of the time. Well, now that I’ve seen this … maybe. It may be perfectly acceptable in many situations, but with strong reds, greens, artificial light and recognisable subjects, it can build in a problem before the real editing has even begun.
Having bought the Cobalt profiles about 18 months ago for my A1, they are pretty much my standard starting points. Depending on the light, contrast of the scene, etc., nowadays I usually apply either Cobalt Colours or Cobalt Flat at the point of importing files into my Lightroom Library. The base packs from Cobalt are not cheap, but, for me, they are worth it to the point that I have them for my A1, my A7CII and my iPhone.
[To be clear: I bought the Cobalt products with my own money, using their discount codes as available. I have no relationship with Cobalt otherwise.]