Computer Graphics with Photoshop

Author

B&W Negatives

Don

2004-09-24, 12:15 pm

Photoshop: 6
Hardware: Nikon LS-50
Software: NikonScan 4.02

Taking a well deserved (!) break from Kodachromes I started playing
with B&W negatives today (Ilford, if anyone is curious). I wonder what
the panel thinks of the less "sensible" of the possible scanning
permutations for B&W negatives:

1. Mono Neg/Grayscale - boooriiing... ;o)
2. Mono Neg/RGB
3. Color Neg/Grayscale
4. Color Neg/RGB
5. Color Pos/Grayscale
6. Color Pos/RGB

For example, scanning B&W negatives as Mono Neg/RGB has obvious
advantages because some blemishes are much more easily corrected with
access to 3 individual RGB channels, converting to grayscale only as
the last step.

I wonder if there are any similar advantages to some of the other
permutations specifically in terms of, say, dynamic range or
sharpness, etc.

For example, at first blush, taking an individual channel from an RGB
scan seems sharper than a grayscale scan which, presumably, started
life as a composite (all 3 LEDs on).

Another example is that fine scratches appear easier to spot if
scanning as Positive and then inverting as the last step, etc.

Don.

Don

2004-09-28, 7:14 am

On Sat, 18 Sep 2004 08:31:29 -0500, "jjs" <John@nopsam.stafford.net>
wrote:

>
>Why?

That was tongue in cheek, hence the smiley...

But, as I just wrote to Mike (and hinted at in the original message)
there is a very serious point here. For example, removing a brown spot
from a B&W negative is much easier if scanning as RGB. The brown spot
stands out much so more on an RGB image than on a grayscale image,
where the brown spot is just as gray as the rest of the image, but
nevertheless still very noticeable as a blemish.

>Bite the bullet and get CS then use 16-bit greyscale.

PS 6 does 16-bit grayscale as well and scanning at maximum scanner bit
depth goes without saying.

Don.