[ChromaNoise]

Hello,

I was wondering if it's possible to create an actual HDR image to be displayed on a HDR monitor/TV, in the same fashion as HDR movies are displayed. I'm not looking for squeezing multiple shots into the sRGB color space, but to potentially display a single shot at the highest maximum color gamut and dynamic range that a HDR display supports (perhaps in the Rec. 2020 color space). Is this even possible?

Ideally, such an image format would have to be as such that it could be viewed on an sRGB monitor as well as a fully fledged HDR display.

Does my train of thought make any sense or what I'm thinking is impossible? If so, why?

Regards,
ChromaNoise

[BigMackCam]

I have no personal experience of doing this, but my initial thoughts are you could set your camera to AdobeRGB colour space, take multiple raw shots, and combine them in post-processing using that same AdobeRGB space.

Clearly, viewing such an image on a device with a narrower gamut would give different results, but it should still look appropriate to that device...

[leekil]

I'm not sure you need anything particularly special to do this. You would have to start with a RAW image, in order to get the maximum number of bits for the HDR TV. Jpeg is 8 bits, and the various HDR formats seem to be 10 or 12 bits. You would need something that could output the higher bit depth to the TV, probably something that supports HDMI 1.4 or 2.0, depending on what the TV's HDR format is. Though depending on the TV, you might be able to play a slideshow from a flash drive. In terms f formats that work on both an HDR display an dan sRGB one, 16-bit TIFF would display on both, though possibly there could be potential optimizations to get the best results depending on whether yo are using an sRGB monitor or an HDR display.

[K1N8]

Start would be a raw developer that supports rec2020 color space.

End of the process highly depends on the actual monitor and the supported inputs or file formats.

GitHub - so-rose/convmlv: A feature-rich RAW developer for Magic Lantern formats.
Seems to be related with rec2020 support

[jbrill]

Perhaps the following page (and related articles) might help:

Elle Stone's Well-Behaved ICC Profiles and Code: Elle Stone's well-behaved ICC profiles and code
Github: GitHub - ellelstone/elles_icc_profiles: Elle Stone's Well-Behaved ICC Profiles and Code

There are a variety of articles concerning color spaces and management.

[Bob 256]

HDR display is over hyped since it's really the processing of the signal which allows a large range of brightness values to be displayed on a typical LED type display device. The fact that an image is 8 or 24 bits relates to the number of graduations in brightness and not the maximum or minimum brightness. More importantly, it relates to the number of colors which can be displayed assuming the display does its job. However if you take an 8 bit and 24 bit image and display them on any monitor or display device without processing the signal, they will appear very similar since the maximum brightness and the minimums are identical and everything between those points is linearly spread. Processing the signal which redistributes brightness ranges creates the HDR effect.

Is there more information in an HDR photo - yes; but to utilize that information on a display, it has to be manipulated somewhat.

[normhead]

With all due respect, it sounds like a load of marketing nonsense.

Most TVs come with a contrast rating. DR is basically determine day the contrast ratio. SO a bright sunny day presents a contrast ratio of 20,000:1.

Worse, contrast ratio numbers have gotten so extreme, there is literally no way to measure some of them. What happens more often than not is the marketing department will come up with the number it needs to sell the product. The engineers will shuffle their feet, and stare at the wall, and magically the TV has that contrast ratio.

HDR in a camera is an attempt to extend the dynamic range being captured by under and over exposing parts of the image then shrinking the additional contrast captured into a range that can be displayed.

HDR in a TV is the contrast (and some would argue colour depth, although colour depth is certainly debatable. You can have a black and white squares in a display with HDR contrast the ratio of the brightest to the darkest part of the of the image, with just black and white, no colour depth needed, so that's certainly a red herring.)

HDR TV s for stills are completely misleading. TVs rate their ratios on dynamic dynamic ranges. They turn their illuminating pixels brighter and darker depending on the scene, then compare the darkest one can get with the LCDs at their darkest setting with the to the brightest, with the LCDs turned up to their brightest setting, and those setting change as the TV scene changes, but that's irrelevant to a still shooter, for whom the scene doesn't change.

My advice would be take you HDR images into a store , plug in your memory stick and see which one you like best. Trying to sort through the marketing literature is not going to provide you with useful information. Most of the time you won't even know what they are talking about.

For still, the best HDR image will be the one with the best static dynamic range. Most manufacturers won't provide that information accurately. Trust your eyes.

Essentially on a bright sunny day the contrast ratio is 20,000:1, you camera shrinks that to maybe 500:1,tops, a TV with good dynamic range, the number I've seen floated theoretically is 4,000:1. A newspaper image will be 60:1 and a magazine photo will be 120:1. Some plasma TVs are supposed to be capable of 4,000,000 to one, but that would require being brighter than the sun to be meaningful. Call me sceptical.

The main thing is HDR capture in a camera is an input device. HDR in a TV is an output device. They are completely different classes of devices and not directly comparable. To best display your HDR images (or any still image) you want the TV with the highest static Contrast ratio.

Your camera reduces a 17 EV scene to 14 EV. A really high contrast TV might be able to get it back up to the 17 EV original scene with a perfect display, but as far as i know there is nothing that comes close. That being said, I'm pretty sure your eye can't handle that. We compensate for the lack of ability to resolve high contrast scenes by staring into the light and dark areas of the scene and having our brain stick the scene together. (Kind of like a cameras HDR.) The idea with prints has always been to reduce the contrast to what the eye can actually handle, so finding a TV that would output more than the eye can handle in one pass is pretty much counter productive. And if memory serves me well, what the eye can handle (non-dynamicly) is considerably less than the 14EV a camera can handle. It's actually necessary to reduce the scene's contrast ratio to a more comfortable, less eye strain producing level for comfortable viewing.

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Last edited by normhead; 03-30-2019 at 03:31 PM.

[kaseki]

Nominally, an OLED TV has an infinite contrast, because any given pixel can be shut off entirely. In reality, there is light in the room hitting the screen -- even an unlighted room is lit by the TV bright areas output -- and bright pixels will propagate some light to nearby pixels by wave-guiding within the display surface layers. There is also a dynamic range quantization limit due to the number of bits driving the pixels.

At the other extreme are the IPS monitors, where gaining its wide angle capability trades off black level to a contrast ratio in the 1000:1 region. These are now the most successful type for higher-end displays used for graphics and photographic editing. Quantization is typically 8+2 (using dithering) but may extend higher in the more expensive displays.

Further, the eye will be dazzled by a sufficiently bright area reducing sensitivity for low (but still color sensitive) light. Add to this the variable spectral sensitivity of the eye, the threshold contrast ratio as a function of light level and target angle subtense, and the usually different from the eye spectral output of the display, and one has a mess [in engineering terms].

In other words, in my view one might get an HDR like effect with a static image in a 4k OLED TV, but most likely the viewer would have to be close and viewing separate parts of the screen sequentially to appreciate whatever added dynamic range was imposed on a given photo image. The real benefit that HDR is intended to achieve is movie theater dynamic range between dark over the entire image scenes and bright over the entire image scenes -- desert in day and candle in cave at night. Even there the viewers' eyes may have to adapt and the cine director may account for that in the rate of change of the scene light levels.

[normhead]

In other words, in my view one might get an HDR like effect with a static image in a 4k OLED TV

Everything looks like HDR on my OLED 4k TV. Because I've been creating slide shows, some high contrast images I've had to go back in and flatten them a bit.

[ChromaNoise]

Thank you to everybody who's responded.

[kaseki]

Everything looks like HDR on my OLED 4k TV. Because I've been creating slide shows, some high contrast images I've had to go back in and flatten them a bit.

As I recall Tex pointing out when I mentioned running out of room for hanging photos: A 4k OLED TV provides nearly unlimited virtual wall space.

[normhead]

As I recall Tex pointing out when I mentioned running out of room for hanging photos: A 4k OLED TV provides nearly unlimited virtual wall space.

And the IQ is simply stunning.

[emalvick]

My thought would be to start with video editing software and see what is out there that can output in an HDR format. I don't think a lot has been done with regard to getting a true HDR image (one that hasn't been tonemapped for your monitor) to an HDR television. But, I would assume there are ways through a capable video editor.

Where you go from there could be hard on the wallet I imagine, but it would probably help give a start.