I've been back over the thread but failed to spot how the black and white conversion was done. The original scans as posted seemed reasonable to me, but the only degree of enlargement I could get was the minimal one obtained by clicking on the image, so it's hard to tell. If the black and white conversion enhances the grain effect, then I'd examine the options there to reduce the effect.
Boringly back on topic.... I think Norman has got himself into a bit of a twist over this 'salt & pepper' phenominon, and is convincing himself to look for complicated answers to a fairly simple question.
I tend to agree with you, B&W conversion hasn't been explained, and common 'niggle' to get such effects, and back mining to the nub of the issue.
I would be interested to have a play with the original scan file, and looking at the individual colour separation layers, and possibly manually merging them to composite B&W.
However, I think that the biggest 'issue' between his experience/results with C41 & E6, is probably SIMPLY down to reversal, and viewing larger digi scale crops, making things more obviouse.
Example shot, from negative, is a little 'bright', suggesting that the original capture may have been a tad over exposed, which in a negative, would result in a greater density in the lighter regions, such as the sky, which is where his speckling is more prominent in the B&W conversion, and where the scanner would be struggling with thresholds and likely generating most 'niose'.
Shooting slide, I certainly used to be that much more conscientious to avoid over exposure, and would, if only to saturate colour, deliberately underexpose by 1/3 stop, and most others were similarly diligent; Consequently I would not expect a scan from slide to struggle so much with 'denser' images to start with, and if there were denser regions, due to reversal, those would most often be 'hidden' in less prominent regions of shadow, rather than wide areas of bright sky.
We then have the issue of the contrast shifts when converting colour to B&W, which are less prominent from a slide, but exacerbated by the colour correction filter from colour negative......
Posted as I was composing:
To convert to B&W I have tried several ways for example the basic conversion using MacPhun, black and white adjustment layer and Image - > Adjustments -> Chanel Mixer in Photoshop. There was no need to use sharpening to exacerbate the effect. For the images I get with the scanner I use the work around seems to be to treat the problem as noise in the colour image before converting to B&W.
I think that Is what you mostly have, 'niose'.
In PS, I would look at and play in the undividual RGB layer separations; observed speckling/noise is most prominent in the sky region, which is predominantly blue, so the blue layer sep is likely to be very flat, and the speckling most obvious in the red rep layer, I'd expect to be densest.
It's likely that the green seperation layer, alone may make for a much more pleasant B&W conversion.. effectively replicating the mechanics of having shot on B&W in the first instance with a yellow filter.
Alternatively, adjusting the contrast of the layers individually, and recombining at different opacities as image layers in a B&W image file, could offer a much more pleasant B&W conversion
You may find reversing the image and looking at it in its original negative form, particfularly in the seperations, to be useful for tweeking contrast & brightness etc too.
These aren't work arounds though, I don't think ANY one touch software, can deal with 'everything' and return idealized pictures from any original media, its all looking for the most pleasant end result. end of the day, computer's just a big pocket calculator, it merely crunches numbers, it doesn't know what you are looking at, or have any 'discretion' or 'opinion' on what the numbers its crunching belong to. Tweeking them then is where we have to do our bit that the calculator cant.
cos it requires SKILL
