3 ms·

For a long time, polaroids have been held as the "this image can't be faked." Somewhere in my collection of lesser used equipment, I've got a Daylab. https://

by shagie 4y ago

For a long time, polaroids have been held as the "this image can't be faked." Somewhere in my collection of lesser used equipment, I've got a Daylab. https://www.instantphoto.eu/pola/pola_daylab_300.htm https://www.instantphoto.eu/pola/pola_daylab_300.htm and I used it to transfer some 35mm slides to 4x5" to practice the various manipulations you can do there (emulsion lifts and transfers). The thing was I had a 35mm slide that was projected onto the film. If I could make a 35mm slide of some sort, I could then make a polaroid of a digital image. Even back then there were a few services that could do it. The idea that you can ensure that the image produced is what was recorded, even two decades ago when polaroids were still a reasonable standard for authenticity of an image shows how easily it can be compromised. Well, maybe not easily but it isn't difficult for a serious hobbyist to create the appropriately constructed image in the desired media. And so what if you sign the EXIF data. That only really guarantees that version of the image. If you adjust the saturation or curves or exposure... or correct for some lens aberration does that EXIF information still match the resulting photo? For that matter, what if you crop it to a square from a rectangle or stitch two images into a panorama?

gpderetta 4y ago
> what if you sign the EXIF data. That only really guarantees that version of the image. If you adjust the saturation or curves or exposure... or correct for some lens aberration does that EXIF information still match the resulting photo? For that matter, what if you crop it to a square from a rectangle or stitch two images into a panorama? While you won't be able to verify the final work mechanically by just verifying the signature, at least, if you bundle the original raw file with the final work, an human (or an AI!) should be able to tell if the final work is at least derived from a real picture. But of course the analog hole is real.
eru 4y ago
> And so what if you sign the EXIF data. That only really guarantees that version of the image. If you adjust the saturation or curves or exposure... or correct for some lens aberration does that EXIF information still match the resulting photo? For that matter, what if you crop it to a square from a rectangle or stitch two images into a panorama? Oh, that's actually possible with cryptographic techniques. Very exciting! See eg https://medium.com/@boneh/using-zk-proofs-to-fight-disinformation-17e7d57fe52f https://medium.com/@boneh/using-zk-proofs-to-fight-disinform... or http://www.cs.tau.ac.il/~tromer/papers/photoproof-oakland16.pdf http://www.cs.tau.ac.il/~tromer/papers/photoproof-oakland16.... Of course, the analog hole stays wide open.
- shagie 4y ago
  Those are interesting, but there's a difference in the manipulations that are done for image for journalism and image for art. That has crop, resize, and grayscale... but not things like "selectively dodge and burn", "adjust the white balance", "skew or rotate to level horizon", or "correct for chromatic and coma aberration in a particular lens." While that is good and useful (and I would be willing to even go so far as saying "needed" for journalistic uses), the transformations available are remarkably limited for artistic use that even represent what can be done in a traditional darkroom.
  - eru 4y ago
    In principle we can do this for all transformations, but performance for arbitrary transformations is still very slow.

by shagie 4y ago

gpderetta 4y ago

> what if you sign the EXIF data. That only really guarantees that version of the image. If you adjust the saturation or curves or exposure... or correct for some lens aberration does that EXIF information still match the resulting photo? For that matter, what if you crop it to a square from a rectangle or stitch two images into a panorama? While you won't be able to verify the final work mechanically by just verifying the signature, at least, if you bundle the original raw file with the final work, an human (or an AI!) should be able to tell if the final work is at least derived from a real picture. But of course the analog hole is real.

eru 4y ago

> And so what if you sign the EXIF data. That only really guarantees that version of the image. If you adjust the saturation or curves or exposure... or correct for some lens aberration does that EXIF information still match the resulting photo? For that matter, what if you crop it to a square from a rectangle or stitch two images into a panorama? Oh, that's actually possible with cryptographic techniques. Very exciting! See eg https://medium.com/@boneh/using-zk-proofs-to-fight-disinformation-17e7d57fe52f https://medium.com/@boneh/using-zk-proofs-to-fight-disinform... or http://www.cs.tau.ac.il/~tromer/papers/photoproof-oakland16.pdf http://www.cs.tau.ac.il/~tromer/papers/photoproof-oakland16.... Of course, the analog hole stays wide open.

shagie 4y ago
Those are interesting, but there's a difference in the manipulations that are done for image for journalism and image for art. That has crop, resize, and grayscale... but not things like "selectively dodge and burn", "adjust the white balance", "skew or rotate to level horizon", or "correct for chromatic and coma aberration in a particular lens." While that is good and useful (and I would be willing to even go so far as saying "needed" for journalistic uses), the transformations available are remarkably limited for artistic use that even represent what can be done in a traditional darkroom.
- eru 4y ago
  In principle we can do this for all transformations, but performance for arbitrary transformations is still very slow.