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> It also sounds like someone made the decision not to backup the raw images because they were “big” - that is actually the one thing they should have backed up
by bscphil 6y ago
> It also sounds like someone made the decision not to backup the raw images because they were “big” - that is actually the one thing they should have backed up because all of the smaller files can be regenerated from the raw ones.
Ironically my experience has been exactly the opposite. It's the demosaic-ed, fully developed copies of my photos that are larger and harder to preserve than the original RAWs. And these files can't be trivially regenerated from the RAWs, either. Let me explain.
The most important issue is that the process of taking a raw image and turning it into an edited RGB-pixel image is not obvious, at all. Tons of steps have to happen in this process, and there's currently no way to describe this process in a way that's compatible with a single open standard or even multiple pieces of software. At all. The steps can be broken down roughly into a series of "instructions", but what those instructions mean (e.g. to Lightroom) is entirely opaque and even secret in the case of closed source programs. Even open source programs, like RawTherapee and Darktable, use entirely different and incompatible approaches, algorithms, and instructions.
What this means on a practical level is that you can preserve your raw files and the instructions for replicating the edits as carefully as you like, but without the exact same piece of software (often even the same version of the program with the same settings and defaults set), your edits are as good as gone forever.
As a result I've had to take fairly drastic steps to make sure my photos are safe. For my older photos, I keep an entire VirtualBox image with Windows and Lightroom backed up along with my raw images, so that I can be sure of restoring exactly the same output files if necessary. (This more-or-less has to be a hacked version of Lightroom because you can't take chances with licensing problems preventing the program from running now that Lightroom is subscription based.) And actually for newer photos, I've moved away from Lightroom to RawTherapee. Even though I feel it's usually inferior, I feel safer since I know the pipeline from raw to burned edit is essentially public. I keep a backed up copy of the RawTherapee source code, but even if that somehow failed someone could make a RawTherapee compatible raw converter from scratch.
So that's why edited images are actually harder to preserve: whereas with raw you can just save them in 2-3 different physical locations and storage devices, to keep the edits you have to take several additional steps and there are more points of failure. Why not just keep the static edited images too? Well, I do that for my most essential photos. But that gets into the other issue, that the edited images are actually larger than the original raws.
If the point is preserving my edits, not just having a copy that's good enough for Facebook, the images have to be lossless. This pretty much means PNG or TIFF, and in fact the latter seems to be necessary since PNG doesn't handle metadata anywhere nearly as well. Unfortunately, while the compression used on raw files tends to be pretty good (which is further aided by the images being mosaiced), the compression algorithms compatible with TIFF are pretty terrible. Add that to the fact that you almost certainly want 16 bit images, in order to preserve as much raw detail as possible (in case you want high quality prints or need to do further editing), and you end up with whopping huge TIFFs. I regularly see my TIFF output files 4-5 times larger than the corresponding raws.
In short, managing backups for a high quality photography workflow is actually a good bit more difficult than it seems at first sight - and how it looks at first is not that easy either!
- wtracy 6y agoBy "raw" I think GP meant the files originally provided by the users, not actual RAW files.
- novok 6y agoAlso I don't think the point of canon's service was to store heavily edited versions of photos, if you were able to edit them at all on their service.
- bscphil 6y agoThat might be the case. Admittedly I don't know much about this cloud platform, and the article doesn't fill in a lot of details, but I would naively have assumed the target audience for something like this would be pro and semi-pro users, who would want to store RAW files, since amateurs and those just looking to share photos would get more out of Flickr, or even Google Photos / Facebook / Twitter / etc.
- deleted 6y ago[deleted]
- ISL 6y agoSo far, I have found that Darktable's edits have survived changes in versions. Someday there will probably be breaking changes, but I haven't yet felt it personally.
- hatsunearu 6y agoevery single "dead" code is still in marketable and isn't accessible unless you try to import a sidecar from a previous version. LR might be shitty but the fact that the guy says darktable has this problem is just silly.
- teawrecks 6y agoI'm not sold. In the cases where you lose the raw vs a post processed image, one of those is significantly more lost information. It may be non trivial to reproduce a post process image from a raw image, but the other way around is usually impossible. In one case you've lost original sensor information, in the other case you've lost some parameters and possibly the algorithm used. The former is infinitely more difficult to synthesize from scratch.