Martin Cassell Oct 6, 2010:

actually I think the two terms just get used interchangeably in common usage (see for example Gert's linked article, below). I was really only offering a pedantic sidenote about the stricter use of the terms.

It seems to me that, depending mainly on readership, asker could perfectly validly either (a) retain a direct translation or (b) override the (arguably) lax usage and 'correct' it to "noisy". Either is good by me.

philgoddard Oct 6, 2010:

OK, maybe symptom was the wrong choice of word - it's a type of noise. But you seem to be agreeing with me that a grainy picture (which is how most laypeople would describe it) is not necessarily the same as a noisy one.

Martin Cassell Oct 6, 2010:

that's not how I'm used to seeing the terminology applied.
graininess is not a symptom of noise: it is a specific class of noise.
the wikipedia article you cite, for instance, uses the term "grain" specifically and solely for the phenomenon caused by the physical structure of conventional photographic film; the only mention in relation to digital imaging is the correct observation that luminance noise can be similar in appearance to film grain.

philgoddard Oct 6, 2010:

Noise is actually an incorrect translation. Graininess is just one of many symptoms of noise, which Wikipedia defines as "the random variation of brightness or color information": http://en.wikipedia.org/wiki/Image_noise

Martin Cassell Oct 6, 2010:

noise v. grain I know the text says grain, but strictly speaking if it's digital, it's noise.

Kimberlee Thorne (asker) Oct 6, 2010:

I ask myself NOW - Why didn't I ever take a photography course when I was younger? This would've come in so handy now - luckily I have you guys to help me...