[Leica] How digital noise is different from film grain (my bestdescription)

[tedgrant at shaw.ca (Ted Grant)]

Adam Bridge wrote:
Subject: [Leica] How digital noise is different from film grain (my
bestdescription)


> Today I was spotting some black and white scans and the difference
> between digital noise and film's grain leaped out at me.
>
> In film, as you move into the blacks, they become denser and denser as
> the grains converge. So blacks are black.
>
> But in digital the noise happens IN the blacks - adding speckles of
> light where there should be black or at least very dark. The worse the
> noise the higher up the luminance values the effect becomes. So at 100
> you see nothing in the very dark areas but by, say 400 there are
> subtle flecks of brightness creeping while while at 1600 these effects
> are moving well up into the mid-tones.
>
> So when you look at a digital image or a film image there is a
> definite quality difference between the way noise and grain operate in
> the dark tones.<<<<

Hi Adam,

So maybe I've been looking in all the wrong places! My viewing has been to
merely look at the overall print without concentrating the looking at the
black areas. However, if the noise is "bright enough" is it not, from your
description, quite easy to see by looking at the black areas of the print
and not on the computer screen.

Although I imagine if I blew the screen image up to 200% I must be able to
see the noise effect without difficulty?  Correct?

ted