HDR and jpegXL photos

2025 05 22

You may not know this about me !! but i love our phone.

theyre a massive friend and help us out with so much, they make us so happy. we're very greatful for them.

now, the webblog we thought we were gonna be bringing this up in was gonna be about the jank things we did before we used our phone for everything. but photographer elysia has made a very exciting discovery.

our phone claims to meet the HDR10 standard, and backs it up by supporting 10 bit imaging and rec2020. the bit depth is essentially how wide the range of brightness values can be, and is associated with making gradients smoother, and rec2020 is a large colour space that has exponentially more colours available to it than the most common colour space, rec709 (aka sRGB).

cool!! this is so cool.

some background on why this discovery made us so excited:

• we've always wanted to make HDR photo
• we've occasionally felt limited by standard DR images
• we just accepted that fact, because HDR displays are inhumanly expensive

we always were aware that phone had unreasonably good screens on them and that, for most people, their phone probably has the best screen in their possession, despite how small it is. we also knew that Apple devices essentially universally have HDR screens, and therefore their cameras also support Jpegxl. but we never considered our phone could be that. we;re still getting used to having a phone that can do everything we want, we thought a HDR screen was too much to expect.

but no! holy shit!

so we've been running around processing photos, especially older ones, giddily seeing how it looks on a HDR display. they're have been... some roadblocks though.

first of all: um. How do I make an HDR image.

Jpegs, which are designed specially for photography... don't... support rec2020 or anythiing above 8bit. so i need a different file format. I also need a camera that takes images with large range of colours as well, and one that can go above 8 bit. then i need a computer program that lets me process the raw image data into something viewable, and that needs to support everything too. Then I need to find a way of viewing it on my phone.

This is how I've gone about this:

Jpegxl for file format. Jpegxl is essentially the goat of image file formats, super good lossless compression, file sizes, load times, and, importantly for us, supports bit depths of 16+, as well as rec2020. Jpegxl is essentially just Jpeg redesigned for the modern world.

However.. there's a snag. Aside from Apple devices, of which I only have airpods ( which i assume aren't useful here... do let me know if im wrong.. ), Jpegxl support is pretty... shotty. Newer professional cameras support it, but my camera is like 13 years old and was mid-end even when it released. There are very few processing softwares that can export or work with Jpegxl. And, most importantly, there are very few ways to view Jpegxl. again. huge exception for mac os and ios.

why did ely still pick it?? well. it's still overwhelmingly the best option available. the other formats i tried are just video formats adapted to photos and are clumsy and dont work that well, and... also i've encoding my photos into 10bit jpegxl files for size and editing reasons for about a year already. ( jpegxl is smaller than jpeg, and still has way less compression artifacts, which makes it much better for long term storage and editing later )

how has elysia been able to do this? well...

creative equipment has always been well ahead of the spec curve compared to consumer viewing devices. Elysia's camera, which has a sensor that is at least 13 years old, likely older, is.. 14 bit. 14 bit may not sound like a big jump from 8 or 10 bit, but remember, it's logarithmic.

and the software we use for processing... is darktable!! which also supports jpegxl. Awesome. So we have lots of headroom to work with, and for old pictures, reprocessing is very easy, since i already have darktable files for them.

the viewing issue is... Harder.

SO i needed to install a plugin for gwenview to even view jxl files, which apparently got uninstalled at some point?? ( rember! ely has been saving jpegxls for at least a year now ! ) thanks em for letting it know i had to do this !

but... viewing on computer really isn't the objective here. we wanna see it on phone. we can KDE Connect over super easily or ADB push. Getting it there is no problem. The problem is software support

so, cus of how i've been using jpegxl for a long time already, I knew that my galleri app, Simple Gallery, already supported them. ... but it doesn't render them correctly

They only show the zoomed out resolution, and so the images are very blurry when zoomed. They also don't seem to display HDR correctly, looking strange unpredictable. think they have like a preview implementation and not the full standard.

Google chrome... used... to support jxl. idk i dont even use chrome i dont feel downgrading jsut for that. likewise its not worth seeing if google files or google fotos work properly cus... if chrome doesnt why would they yknow.

firefox nightly has a flag for it but firefox famously doesnt support HDR anyways so. also like, firefox just is several years behind web standards anyways ( nice for forgetting scroll animations and animation discrete css... ) so not much hope there.

is there anything we can use. well...

this seems to work...

it seems to have previously had an issue with HDR but it seems like the library it relies on fixed it upstream so... Yay...? still insane that this is all it found. and im not entirely sure if its even displaying properly

it is kinda intersting that the developer told someone to use Simple Gallery instead for some reason? someone was kind enough to tell them that they had a better viewing experience though.

but yeah like

i know google has a vendetta against jpegxl and all but like.. HDR?? feel like that should be better supported. it's not like i could get heic or avif to work at all.. so we have to accept this. might check older version of chrome at later date but not now.

if the viewer would like to tag along, you may own an HDR phone as well ! especially if you have an iphone. Tap-hold the empty image box to get the download prompt ! on android, the app i linked can be used to display them properly ! Safari and other webkit browers are able to natively display JpegXL as well, so if you have access to safari, or a browser like GNOME Web ( epiphany ), you can also see the images right in your browser! although probably not HDR versions ( idk ). ios seems to have hdr support mainly in the gallery

anyways with that all out of the way, what is HDR? in photographyy, HDR refers to multiple different exposures to create a more balanced scene. In video, HDR refers to wide range of display brightnesses and higher contrast range. We're talking about the latter, or "real HDR"

why would I use HDR? well...

take this image:

( download to view on computer or have a apple device or later images will have regular jpeg version )

There isn't much contrast in the photo normally, but HDR gives it a lot more contrast with brightness. HDR is basically just darker darks and lighter lights, and the file space to have that extra detail. This iamge takes advantage of it by being higher contrast on HDR screens without losing any details.

some images also just feel Made for HDR:

oftentimes i feel this comes up with photos that I need to give a flat tone curve to get all the details i want normally. stuff like this:

in order to get all the details on a SDR display, I need to flatten the contrast curve a lot ( shown in linked jpeg ! ). with HDR, I can still have those details while also having more contrast.

it isn't just bright scenes that benefit too, I've found night scenes like this benefit a LOT:

HDR gives me so much more wiggle room for the dark, and lets me put a lot more drama and mood in the scene by crushing the shadows ( or at least, that's how it appears on my SDR computer monitor while editing ), while still letting me get the details I want. The HDR version of this image feels so warm and bright despite having so much more darkness.

In general I've found that, not only is increasing shadow depth and detail very important for HDR, but it's also often necessary. The photos with older jpeg versions have been completely re graded and processed so that they dont look weird ( had a problem of images coming out WAY too bright on first pass, and you can still see some of that here). HDR screens are very bright, and the soft shadows in a lot of my SDR images don't look like shadows at all when viewed in HDR, and I've had to go back in and change the tone curve to be higher contrast without ruining the vibe.. That's why a SDR screen makes the shadows look so deep when viewing an HDR image ( at least I think )

a big barrier for my nighttime shots has always been the contrast. There is so much contrast in a scene with lights in it, and it's always been so hard to balance the detail. But HDR makes images like these look just magical and ethereal. It's so pretty and really just not a look I can replicate without HDR.

although.. it definitely matters on the photo, and is hit or miss. Even for night scenes that should have a lot of contrast, it doesn't always hit.

and.. Yeah. Images where having crunchy shadows is the look i was going for kinda fall flat in HDR.

outiside of what is just night time, the little brightness bump also makes clear skies, sunsets, or other bright objects like snow really nice. It isn't amazing the same way the night glow and contrast is in HDR, but it's just nice.

so... yeah.

HDR is weird cus it feels like midtones benefit a lot from it. I don't care for it when I ultra high contrast or ultra low contrast. But everything in between feels like it benefits.

learning to edit the images in a way i liked was therefore interesting: i thougth at first i needed to leave the tone curve flatter so that i got more detail in the final result. i was very wrong, and misunderstood how it worked, and actualyl needed to increase contrast on most images to have them look right on an HDR screen. But not too much, and then it would start looking bad again.

and like yeah if i was going for a very low contrast or ultra high contrast look already than i dont really think hdr makes any imrpovement at all. like for the tram crossing photo where i think the SDR version just looks... better.

oveerall though, still very excited. I am really excited to play with this more on night photos. night photos have already kinda been my favourite ever since i started photography like 5+ years ago, but now its so much more enticing because i have so much more flexibility now. Framing shots is so hard when you're limited to an SDR colour space.

and on colour space.... it seemed a lot more impactful than the bit depth. Like i made a bunch of these and others that i thought would show banding issues in gradients and just... didnt notice it. I think my computer screen might be dirty, cus im fairly confident they're there. The only photo i think i noticed a real difference with the bitdethps was the cool bridge one, even compard to clear flat colour sky images. Maybe just not looking hard enough.

here's an image with a clear sky in both 8bit and 10bit if any of you wanna do some pixel peeping for me. I can't see a difference. Shoutout to the big ass tower. Also yes the crane was curved like that irl

and that's that! i think. here's some classic fan favourite elysia images that I re processed but didn't have anything to say about them. They're noticeably nicer in HDR, but !