Digital quality (vs 35mm): Any real answers?

Hi.

I'm still wondering about how good the image quality of modern digital
cameras (especially SLRs) really is, in particular how it compares with
35mm film. I've seen many articles on the subject on the Net, but few of
them seem to give you a lot of tangible information (I want to see the
numbers, please), and I can't help feeling that tests they refer to are
usually done to prove a point, i.e. that digital cameras are as good as
35mm, which is not the way you do proper research.

To say a few words about myself, I'm working for a company that makes
high-accuracy, large-format scanners, so I'm not particularly impressed
when I hear e.g 6 million pixels (you need to talk about *billions* of
pixels if I'm really going to listen), and the word "interpolation"
leaves a bad taste in my mouth. But this also means I know that high
resolution isn't everything, of course; parameters like geometric
precision or signal-to-noise ratio also count a lot.

Be that as it may, some of the questions I'd like to have answered are
these:

1. What is the resolution of a 35mm film anyway? I think I read
somewhere that a colour negative is at least 3000dpi. Is that correct?
How about black&white? (Yeah I know, a film doesn't have pixels in
exactly the same sense as a digital image, but it *is* made up of
discrete elements after all.)

2. What about the print? 300dpi?

3. I know that the most common sensors are made up of individual
elements for the read, green and blue channels, arranged in a special
pattern, whose data is somehow interpolated into RGB pixels. But what
exactly does e.g. 6 megapixels mean in that context? Does it mean that
the sensor has (just) 6 million elements, or that data from a higher
number (like 18 or 24 million) is combined into 6 million RGB pixels?

The same question more bluntly put: When Canon/Nikon/Pentax is talking
about 6MP, is that just a big a lie as the one about 10MP on Sigma
cameras? (I'm hoping not, as I think the Sigma/Foveon way of counting
really takes the cake.)

4. Can the inaccuracy associated with the above mentioned interpolation
be quantified and/or measured against e.g. the error introduced by
scanning a negative with a film-scanner? And how does it compare with
pixel interpolation in the scanning sense?

5. And how about those other parameters I mentioned briefly above - like
different kinds of geometric distortions, noise, flat field bias etc.?
Can those be compared with the ones of plain old film?

6. And the chromic aberration effects? How serious are they these days?
And are the full-frame sensors that are actually found in some high-end
cameras now, in any way comparable to film in that respect?

Well, maybe some people will say I have a somewhat critical or
conservative attitude towards digital cameras, but I actually think you
ought to be a bit sceptical when something "new and wonderful" comes a
long; new technology is too often introduced for technology's own sake, IMO.

- Toralf