David,

Then your quest would largely depend on the actual techniques used to enhance the print. Again, more "traditional" tools can be explained reasonably easily, again using things like "an unsharp mask was performed which finds the difference between light and dark edges". Once they need to know HOW that's done, there's plenty of documentation on the process without having to go into a specific algorithm used - at least I would think.

When you talk about resizing an image using Bicubic resampling, you can obviously speak to the issues surrounding the removal of pixels to accomplish a smaller size, but if I recall correctly, Adobe uses a proprietary algorithm to re-sample. If that's called into question, then almost certainly someone from Adobe would have to be issued a subpoena.

The "fit and finish" of it all is, I'm not 100% sure that this forum is going to be the best place for your answers. Rather, I think that if you've documented the steps performed, you would have to list those steps out one by one, then use information available in the help file for understanding exactly what a particular step does. Then, do a google search on some of those techniques to see the theory behind it.

At some point, a good attorney with a good expert witness (for the other side) can ALWAYS challenge a particular technique and the algorithm used (for example in using a blend mode). Let's face it, the fact that you are shifting pixels, removing them, darkening them, is changing the image. At that point, you would need someone who can discuss the issues surround the algorithm, what it does and what it does not do.

Forensics with digital imaging can be tough since there is always the argument that you are fundamentally changing the image. However, digital enhancement of video footage to, say, identify a car at a crime scene from a video still, goes reasonably unchallenged.

I'm not sure I have provided much more information than you had when you started your quest, but again, I'm not sure this forum will be able to help much.

<shrug>

Peace,
Tony

Terry Morse

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