Scanning B&W negs. Does it make sense to favor one channel over the others?

I'm scanning B&W on a Minolta Scan Multi Pro. I've heard that the

blue channel will show more noise though it also seems to show more

detail. Is there any reason not to use just one channel?

No, it's not that unusual. Many people do the same thing with

digital cameras. Usually with scanners the blue channel isn't as

big of an issue as it can be with digital cameras.

 

If you like the contrast and detail of a particular channel, and if it's

suitable for your uses, who cares what anyone else says?

When we have people convert from color to grayscale we make

sure they look at the full image in gray as well as each of the

channels. sometimes certain ones are more appropriate.

 

Noise is only a problem in the blue channel (or any channel) if

you see any. If you don't then don't worry about it!

The blue channel frequently shows more garbage in color neg films. It doesn't seem to be a problem with slide or true B/W films.

 

Chromogenics, being based or color neg technology, might exhibit the same problem.

 

I strongly suggest scanning your B/W film with all color channels and then tweaking later on in Photoshop. Scanning with one channel, or simply using monochrome scanning channels simply results in throwing information out at the hardware stage that is best left in the image.

When scanning B&W (100TX, HP5, TX, Delta3200) with Canon FS4000/Vuescan in 16bit image mode and look at the different channels in Photoshop (after inverting and rough and conservative levels), invariably the green channel seems to be the crispest with most detail. Why don't you look for yourself with Photoshop what channel looks best for your purposes?

I concur re above comment on green channel when scanning b/w, with Dimage Scan Dual II. Blue and red channel seem out of focus, by comparison. For now, I'm used compilation of all channels, but interesting...

I rented a film scanner (Polaroid SprintScan) and spent a whole weekend earlier this month just scanning b&w negatives as 'Generic Negative/16 bit'... Man, this takes forever; only got through about one year's worth. argh.

 

<p>However, I quickly learnt that it takes even longer to load them all in and tune them. Each channel usually has 'something' that I like and something that I don't. For example, in portraits, the red channel has such a clear rendering of skin tone but is very soft. The Blue channel has a harsh rendering of skin tone but usually good background detail. Green is usually somewhere in between, and it varies for every single image...

 

<p>I started by playing with channel mixer, but it's kind of annoying because it's hard to compare whether 60/30/10 looked better than 50/30/20, since you can't just flip between them...

 

<p>So I created an action to combine channels and let me choose one for further tweaking. My so-called workflow is then:

 

<p><ul><li>

Load image

<li>Manually drag endpoints in each 16 bit colour channel (R,G,B) so that I'm not clipping anything (manually, since auto-levels seems to do a crappy job.)

<li>Tweak the RGB pseudo-channel in levels since above moved it around. Set endpoints and move middle slider (gamma) if desired.

<li>Run Action, which contains:

<ol><li>Convert to 8-bit mode

<li>Calculations: Multiply Red by Green to get new channel

<li>Calculations: Multiply Red by Blue to get new channel

<li>Duplicate Red Channel

<li>Auto-Stretch contrast on Red Copy Channel (to give different values)

<li>Calculations: Multiply Red Copy by Green to get new channel

<li>Calculations: Multiply Red Copy by Blue to get new channel

<li>Calculations: Multiply Green by Blue to get channel GB

<li>Calculations: Multiply Red by GB to get new channel

<li>Calculations: Multiply Red Copy by GB to get new channel

<li>Delete channel Red Copy

<li>Delete channel GB

</ol></ol>

 

<p>This gives me six different "basic interpritations" of the image in greyscale that I can quickly compare just by clicking on them in the channels pallete. For most images, the middle two are the best, but not all. I then pick one, tweak it if necessary, then convert to greyscale to get rid of the others.

 

<p>Disclaimer: I'm still a beginner. If anyone has any better ideas, I'd be happy to hear them.