HDR: The 2nd Commandment (updated)

“Frames that have a wider variety of contrast and a higher contrast range from the source media work best in HDR and therefore look best.” Aidan Farrell, colorist, The Farm

If the first inviolable rule of HDR is to not clip the signal, the second must surely be that scenes have adequate contrast. We just watched Fancy Dance (2023) on Apple TV+, and many of the shots looked like all the life had been completely sucked out of them.

The group of four images above, intentionally chosen for a study of the impact adaptation and luminance changes have on viewer discomfort, are examples of low contrast scenes that might not necessarily work well in HDR. The researchers remark:

“It is important to note that the images in this study represent unusual cases of HDR content, where the luminance distribution is fairly flat. Typical HDR imagery utilizes the high peak luminance more dynamically and, usually, depicts lower mean values. The selection of these images was intentional so that observers would have a consistent viewing experience regardless of what region of the image their gaze attended to.” – The Impact of Adaptation Time in High Dynamic Range Luminance Transitions. Jake Zuena and Jaclyn Pytlarz. Dolby Laboratories. Journal of Perceptual Imaging, 2024.

If you’re unsure whether your scenes have adequate contrast, Ed Lachman’s EL Zone can help in that regard. Matthew Allard writes:

“Above we can see another example of how useful EL Zone is. In this case, I have exposed for 18% grey, but you can see that this is a very low-contrast scene where there is only a difference of around 7-8 stops between the brightest and darkest parts of the scene. This is where EL Zone becomes very useful because it then allows me to look at what I need to do to my scene if I wanted to add more contrast.”

When lit properly, even the monitor looks more interesting!