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What is HDR, anyway?

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791 points _kush | 4 comments | 14 May 25 12:46 UTC | HN request time: 0.709s | source
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dahart ◴[14 May 25 16:48 UTC] No.43986653[source]▶
It seems like a mistake to lump HDR capture, HDR formats and HDR display together, these are very different things. The claim that Ansel Adams used HDR is super likely to cause confusion, and isn’t particularly accurate.

We’ve had HDR formats and HDR capture and edit workflows since long before HDR displays. The big benefit of HDR capture & formats is that your “negative” doesn’t clip super bright colors and doesn’t lose color resolution in super dark color. As a photographer, with HDR you can re-expose the image when you display/print it, where previously that wasn’t possible. Previously when you took a photo, if you over-exposed it or under-exposed it, you were stuck with what you got. Capturing HDR gives the photographer one degree of extra freedom, allowing them to adjust exposure after the fact. Ansel Adams wasn’t using HDR in the same sense we’re talking about, he was just really good at capturing the right exposure for his medium without needing to adjust it later. There is a very valid argument to be made for doing the work up-front to capture what you’re after, but ignoring that for a moment, it is simply not possible to re-expose Adams’ negatives to reveal color detail he didn’t capture. That’s why he’s not using HDR, and why saying he is will only further muddy the water.

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1. QuantumGood ◴[14 May 25 17:15 UTC] No.43986960[source]▶
Adams adjusted heavily with dodging and burning, even working to invent a new chemical process to provide more control when developing. He was great at determining exposure for his process as well. A key skill was having a vision for what the image would be after adjusting. Adams talked a lot about this as a top priority of his process.
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2. Demiurge ◴[14 May 25 17:54 UTC] No.43987387[source]▶
> It's even more incredible that this was done on paper, which has even less dynamic range than computer screens!

I came here to point this out. You have a pretty high dynamic range in the captured medium, and then you can use the tools you have to darken or lighten portions of the photograph when transferring it to paper.

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3. staticautomatic ◴[14 May 25 20:02 UTC] No.43988606[source]▶
Contact printing on azo certainly helped!
4. jrapdx3 ◴[14 May 25 20:19 UTC] No.43988754[source]▶
Indeed so. Printing on paper and other substrates is inherently subtractive in nature which limits the gamut of colors and values that can be reproduced. Digital methods make the job of translating additive to subtractive media easier vs. the analog techniques available to film photographers. In any case, the image quality classic photography was able to achieve is truly remarkable.

Notably, the dodging and burning used by photographers aren't obsolete. There's a reason these tools are included in virtually every image-editing program out there. Manipulating dynamic range, particularly in printed images, remains part of the craft of image-making.