During the holiday season in late 2016, UHD TVs were flying out the doors, so It appears that UHD is now fully upon us as consumers. In addition to having a sharper picture (UHD has four times as many pixels as HD), many of these TVs feature something called HDR. HDR promises previously unseen levels of brightness, contrast, and color performance. Brian Florian has prepared a veritable smorgasbord of information for you, our readers, which I know you are going to enjoy. The article took 6 months to write the text and prepare original artwork. I feel confident in saying that it is the most comprehensive discussion and dissection of HDR that has ever been written in any A/V consumer publication anywhere, perhaps not on every inhabited planet in the universe, but certainly on ours.
There are many acronyms (abbreviations) in this article, and they are highlighted in red. Just place your mouse over the acronym, and you will see an explanation of what it means. You can also click on the Glossary, which will open a new window, and then you can refer to the Glossary while you read the various sections of the article.
I am sure you will have questions about this technology, so please ask them in the comments area at the bottom of any of the sections that you have questions about.
Secrets Editor-in-Chief, John E Johnson Jr.
HDR, or High Dynamic Range, is a collection of video technologies and standards which collectively represent a huge potential in terms of pushing forward the quality of the moving images we capture and watch, yet it is currently enshrouded in much myth, misunderstanding, and confusion. Through this set of explanatory articles you will learn not just what HDR is, but also what it is not. By understanding how HDR works you will be in a position to make informed decisions on which standards to favor, what equipment to spend your money on, and so forth.
In simplest phrase dynamic range in the context of video is the difference, or the range, between the darkest parts of the image and the brightest. Throw the word high in front of it and the implication is that we are talking about more dynamic range than we had before.
This discussion will be presented in six parts, covering dynamic range fundamentals, display technology, resolution and color concepts, calibration and design issues. This is a lengthy topic; each section is cross-referenced to previous and following sections for ease of reference. Also, since the topic is loaded with acronyms, an accompanying glossary will be accessible as you read, for a quick reference.
To get a proper understanding of HDR we first need to revisit SDR , or Standard Dynamic Range, particularly in terms of luminance calibration. We contrast that with HDR, highlighting key differences.
In this section we will also discuss how HDR is enabled in different display technologies including LCD and OLED, and take a glimpse at Future Technologies.
In this section we will take a brief look at sourcing content for HDR, in particular explaining the difference between HDR video and HDR photography.
In this section we will touch on resolution as it relates (or rather doesn’t) to High Dynamic Range (HDR) ). We will look at color reproduction, finding commonality with Ultra High Definition (UHD) standards, and explore differing color spaces, notably, BT.2020 and P3 , against the capacity of human vision.
As a vehicle to understanding HDR we will review the calibration process for SDR with a focus on how it differs from the calibration process for HDR. Featured in this and the following section is the latest version of SpectraCal’s CalMAN software (this will not, however, be a lesson in how to calibrate a TV).
Calibration in the HDR world is described for both Dolby Vision and HDR10. Dolby Vision calibration uses the Dolby Vision Golden Reference to define unique model specific targets. The process for HDR10 currently has some holes in it.
Any new technology has growing pains and there are some major design issues with HDR. I discuss some of these issues and the challenges presented for calibration. Bottom line, just because a TV is marketed as “HDR” does not necessarily, in our view, qualify it as such.
I would like to thank Stacey Spears and Tyler Pruitt for their assistance in the preparation of this article.
(Disclaimer: any and all images presented are simulations only. It’s impossible to actually show you any HDR or ITU-R BT.2020 images because you are viewing this on a computer, tablet, or phone screen which simply cannot display them).