From: Douglas Johnson on
"Charles" <charlesschuler(a)comcast.net> wrote:

>Ran across some interesting posts about faked photos. Led me to this:
>
>http://www.scientificamerican.com/article.cfm?id=5-ways-to-spot-a-fake
>
>Then, ran across some opinions that RAW files cannot be faked? Wait a
>minute! The demosaicing algorithms are public knowledge. Algorithms are
>simply mathematical manipulations that surely are reversible. What am I
>missing here?

Not all mathematical manipulations are reversible. Consider simple addition. If
the answer is 5, you don't know whether it was 1+4 or 2+3. -- Doug
From: Charles on

"Douglas Johnson" <post(a)classtech.com> wrote in message
news:b303n5pvhuvass5npb27mnpcq21n35mi3t(a)4ax.com...


> So RAW files can probably be faked. You just have to be careful about it.

I think they can and I think they will. My guess is that digital images,
both RAW and JPG, will be weak evidence (or inadmissible) in many courts of
law. Not an important issue to me ... just curious about it.

Thanks to all who responded.


From: Andrew Haley on
Charles <charlesschuler(a)comcast.net> wrote:
>
> "Douglas Johnson" <post(a)classtech.com> wrote in message
> news:b303n5pvhuvass5npb27mnpcq21n35mi3t(a)4ax.com...
>
>
>> So RAW files can probably be faked. You just have to be careful about it.
>
> I think they can and I think they will. My guess is that digital
> images, both RAW and JPG, will be weak evidence (or inadmissible) in
> many courts of law.

It's no different from any physical evidence: counsel has to be able
to show that there is a proper chain of custody. Without that, the
evidence will be indamissible. This is so with film, too, and is not
different from the rule that you have to prove a chemical analysis has
not been tampered with. See
http://federalevidence.com/taxonomy/term/59, and

"In order to be admissible, a photograph must be shown to be an
accurate representation of the thing depicted as it appeared at the
relevant time. See United States v. Stierwalt, 16 F.3d 282, 286 (8th
Cir. 1994)"

Andrew.
From: Wolfgang Weisselberg on
Charles <charlesschuler(a)comcast.net> wrote:

> I think they can and I think they will. My guess is that digital images,
> both RAW and JPG, will be weak evidence (or inadmissible) in many courts of
> law.

Then no email would ever be evidence, since it is so trivial to
fake ... fingerprints are fakeable, too.

-Wolfgang
From: Michael Benveniste on
On Wed, 10 Feb 2010 14:44:53 -0600, Andrew Haley wrote:

> It's no different from any physical evidence: counsel has to be able to
> show that there is a proper chain of custody. Without that, the
> evidence will be indamissible. This is so with film, too, and is not
> different from the rule that you have to prove a chemical analysis has
> not been tampered with.

Not quite.

A chain of custody _is_ necessary if one needs to prove something about
the physical photograph itself in a criminal trial. Such might be the
case, say, if possession of the photograph itself is illegal or when
forensic evidence is recovered from the physical print.

It's rarely necessary when a photographic is being admitted for the
image it purports to represent. In fact, usually the photographer
need not testify.

> "In order to be admissible, a photograph must be shown to be an accurate
> representation of the thing depicted as it appeared at the relevant
> time. See United States v. Stierwalt, 16 F.3d 282, 286 (8th Cir. 1994)"

That can be done, and usually is done through witness testimony. It's
often as simple as:

Q: Witness, I present this object to you and ask you to examine it.
Does this photograph fairly and accurately portray the scene you
observed at the location and the time in question?
A: Yes.
Q: Your Honor, move to admit.

In the case you cite, the court said "The photographer spoke to no one
who was present the night of the incident, and no witness testified that
the photograph was an accurate representation of the view from the
Explorer into the Omni when the drug deal took place." The court
did not even hint at a chain of custody requirement.

If the photograph is the used to draw additional scientific results,
such as the length of skidmarks, etc, the court can require additional
technical information such as shooting data. In the case of an
unattended photograph, testimony is normally required as to the
proper operation of the equipment which produced it.

Once admitted, of course, the opposing side is free to cross-examine
and otherwise challenge the authenticity of a photograph. That then
becomes an issue for the trier of fact to decide.

--
Mike Benveniste -- mhb(a)murkyether.com (Clarification Required)
Its name is Public opinion. It is held in reverence. It settles
everything. Some think it is the voice of God. -- Mark Twain