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08/04/2007 07:08:07 PM · #1 |
I am a bit new here..and have a few questions..I saw in the challenge rules that there were some guidelines on how much you can edit your submission..
1)does photoshop keep a copy of all the steps you have taken to modify the file..or is the decision made purely on the experience of the council members
2)as far as I know, the exif information can easily be tampered with..yesterday itself i found two softwares [edited] and [edited] to do so...I think even photoshop can do it reliably...so how do you know that the person taking the photo has not indeed tampered with the photo...just so that he can have a better photo.
Message edited by L2 - Edited to remove the names of the software that will get someone banned.. |
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08/04/2007 07:09:45 PM · #2 |
1. Photoshop can be set to log changes.
2. The DPC site council does not reveal its methods of detecting EXIF tampering. They're widely believed to have magical powers. Don't mess. |
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08/04/2007 09:42:46 PM · #3 |
| ssoo should we have photoshop log changes and if so, how? |
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08/04/2007 10:10:50 PM · #4 |
Originally posted by chris48083:
ssoo should we have photoshop log changes and if so, how? |
solid question. I too would like to know this. Save me some time writing it myself.
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08/04/2007 10:20:21 PM · #5 |
We look at this stuff every day. We're very familiar with what the EXIF should look like for any given image. When EXIF is tampered with, there is a very high probability that we will catch it.
The penalty for a first offense is a permanent ban from the site, without warning, so I don't recommend experimenting.
~Terry
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08/04/2007 10:21:29 PM · #6 |
Originally posted by chris48083:
ssoo should we have photoshop log changes and if so, how? |
You don't have to have Photoshop log the changes, as long as you can tell us what they were. The more specific you can be, the better.
I don't know how to turn that feature on, I'll defer to a Photoshop user to answer.
~Terry
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08/04/2007 10:23:41 PM · #7 |
Edit>>Preferences>>General,
and check history here: |
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08/04/2007 10:51:30 PM · #8 |
Originally posted by ClubJuggle:
We look at this stuff every day. We're very familiar with what the EXIF should look like for any given image. When EXIF is tampered with, there is a very high probability that we will catch it.
The penalty for a first offense is a permanent ban from the site, without warning, so I don't recommend experimenting.
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Having said that, should the SC be allowed to enter challenges?
(please don't flame the messenger--I'm just being the devil's advocate and am just asking the next obvious follow up question to your message) :-( |
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08/04/2007 10:58:30 PM · #9 |
Being able to recognize tampering does not equate being able to tamper without being discovered. For example, that's what digital signatures are all about. You can verify that the data hasn't been tampered with, but there is no way you can tamper with it in a nondetectable way.
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08/04/2007 11:30:47 PM · #10 |
Originally posted by srdanz:
Being able to recognize tampering does not equate being able to tamper without being discovered. For example, that's what digital signatures are all about. You can verify that the data hasn't been tampered with, but there is no way you can tamper with it in a nondetectable way. |
With all due respect, this is incorrect.
Digital Signatures prove that an entity (person, web site, etc) is who they claim to be.
A "hash" proves that digital content has not changed (altered/modified). For a hash to be generated, you would have to have the content initially. In other words, a photog/camera would have to generate the hash code. That hash would have to be sent by the photog to the SC. The photog could modify the EXIF and then generate a hash code, and so on and so forth...you see...it wouldn't work.
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08/04/2007 11:38:45 PM · #11 |
Sorry for being incorrect and not precise. What I was thinking about is Encrypted Message Digests. The company, (e.g. Canon) would have its own private key unknown to anyone other than them, and they would publicize their public key. Camera would calculate message digest (or hash as you put it) and encrypt it using the private key.
SC would then take the image, get the signature, decrypt it with public key, calculate message digest themselves and compare the two.
This probably does not happen in reality, but that would confirm that the image wasn't tampered with.
Am I correct now :-) |
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08/05/2007 12:31:37 AM · #12 |
Originally posted by ClubJuggle:
The penalty for a first offense is a permanent ban from the site, without warning, so I don't recommend experimenting.
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but I thought the penalty for
1st DQ in last 25 submissions: No penalty
2nd DQ in last 25 submissions: 1 week suspension of submission privileges
3rd DQ in last 25 submissions: 2 week suspension of submission privileges
4th DQ in last 25 submissions: 4 week suspension of submission privileges and 3 months of required “pre-submission” of proof file.
Another question in the basic editing rules its stated
1)you can include existing images or artwork as part of your composition as long as the entry does not appear to consist entirely of a pre-existing photograph in order to circumvent date or editing rules or fool the voters into thinking you actually captured the original photograph.
2)you must create your entry from a single capture.
Are they not mutually exclusive?
Message edited by author 2007-08-05 08:26:21. |
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08/05/2007 04:31:27 AM · #13 |
Originally posted by thinktank:
Originally posted by ClubJuggle:
The penalty for a first offense is a permanent ban from the site, without warning, so I don't recommend experimenting.
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but I thought the penalty for
1st DQ in last 25 submissions: No penalty
2nd DQ in last 25 submissions: 1 week suspension of submission privileges
3rd DQ in last 25 submissions: 2 week suspension of submission privileges
4th DQ in last 25 submissions: 4 week suspension of submission privileges and 3 months of required “pre-submission” of proof file. |
Hi Thinktank,
If you read a couple sentences beyond what you quoted, you would have seen "If a user is found to have intentionally violated the Challenge Rules, the above penalties will be in addition to any assessed for the violation itself." (Emphasis added.) The penalty for EXIF tampering is an instant and permanent ban from the site.
Originally posted by thinktank:
Another question in the basic editing rules its stated
1)include existing images or artwork as part of your composition as long as the entry does not appear to consist entirely of a pre-existing photograph in order to circumvent date or editing rules or fool the voters into thinking you actually captured the original photograph.
2)create your entry from a single capture.
Are they not mutually exclusive? |
This refers to using a pre-existing image as part of a composition and taking a new, timely capture of that image AND something else. A good example of this concept is:
HTH,
L2 |
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08/05/2007 06:24:34 AM · #14 |
Originally posted by thinktank:
Another question in the basic editing rules its stated
1)you can include existing images or artwork as part of your composition as long as the entry does not appear to consist entirely of a pre-existing photograph in order to circumvent date or editing rules or fool the voters into thinking you actually captured the original photograph.
2)you must create your entry from a single capture.
Are they not mutually exclusive? |
The first rule you quoted covers when you may or may not take a photograph of another photograph or artwork. The second says that you may not combine multiple images in post-processing. As an example, generally speaking, you can use a second photograph as a backdrop in your setup (see the example that L2 posted above) but you may not paste it in during post-processing.
~Terry
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