Finer grain in cheap iso400 colour film than in iso100 b/w? Really?

[Emil]

Last night i printed my backlog of negatives from the last year, and i came across some colour negatives (a cheap kodak iso400 - store processed) and decided to print some of these too on b/w paper for the hell of it. I was stunned to see that the grain was an order of magnitude finer than on any of my carefully home developed b/w films! What's going on here?

[Anon Ymous]

There's a major difference between the traditional BW films and C41 films:


The granularity of classic BW films increases with density. It means that highlights are more grainy than shadows.


The granularity of C41 films decreases with density. It means that highlights are less grainy than shadows.

It's far more likely to spot grain at mid to light tones.

[polyglot]

C-41 has dye-clouds with soft edges. So while the grain doesn't look like much, the resolution may not be quite so great.

[markbarendt]

Nothing empirical but 400 and 800 speed C41 constantly amazes me.