b2b b2c infomations

This is an excellent question, it forced me to really think about how I’ve used the terms and whether that usage is justifiable. A star to you.
Grain and noise are artifacts of the process – the visual grain in a print is a result of the physical grains of silver in the emulsion of the film. It may or may not be employed for aesthetic effect, but it is always present to a varying degree depending on the film speed and development.
Noise is also a result of physical processes on the sensor – how long the light hit the sensor, how warm the sensor became as a result and the ISO setting of the camera for the given exposure. It is also indicative of the quality of the camera itself: bigger is better in digital. Noise is also manipulated for aesthetic effect but is generally considered undesirable. A lot of effort is expended to eliminate it (Noise Ninja, better sensors, et cetera.)
The terms are analogous in their concept, that grain and noise are the remnants of the process of making the photo although they are not in fact the same thing. When I’ve said something along the lines of:
the grain/noise is dependent on the ISO of the film/sensor, I’ve meant that the results will be similar: the film image will have a lot of grain and the digital image will have more noise if a higher ISO is used. I considered the technical differences of small consequence and did not go deeper than that. This is an error.
In really thinking about your question I realized I have a glaring prejudice: I don’t like grain and have always considered it a form of “noise” – even long before digital photography was introduced. So I allowed my own preferences to limit my exploration of this question. Thank you for bring it to my attention.

Grain is a history lesson to someone that started with digital, and is irrelevant to them. I know the difference, but only because I chose to learn some history of the art. Digital has been around long enough that some working pros have never shot film….
I wish it wasn’t this way, and I honestly wish I had learned on film. I feel I would be better for it.

If you are referring to me, I never called myself a pro. I’m an amateur at best, and I wasn’t trying to use technical terms when I asked my questions. The pictures looked “grainy” so I called them “grainy”.
My apologies for being ignorant. I came to Yahoo Answers in the first place to learn more about my camera, and people have helped a lot. Including you. Now I know that my pictures are “noisy” and not “grainy”.

Maybe some are old “filmies” still using those terms..like when I call a CD a record.