Most Compelling B&W Scans on 4990 w/48 bit Scan and PS Conversion?

[Jeremy Moore]

I take a combination of 75% green channel and 25% red channel on my pyrocat negatives (stained negatives) in the channel mixer from my 48bit rgb scans. I have an action that opens up the scanner software, I do the scanner driver stuff and hit scan, and once it's in photoshop the action automatically does the channel mixer, converts to grayscale, opens the Save As... dialog box so I can choose where to save my image, and then it closes the file.

I use 75/25 because that seems to give me the best combination of tones and minimal noise for MY workflow. Epson 10000XL scanning 8x 4x5 negatives at a time at 2000dpi which will eventually be printed to 16" x 20" @ 360dpi.

[Kirk Gittings]

Good point Jeremy, because of the color of the stain, Pyro negatives are a bit of a different animal.

[DigitalDude]

Thanks to many for good input/feedback--here are some of my early conclusions based upon some controlled tests. Standard Disclaimer, of course, YMMV:

1. It is indeed worth scanning at 48 bit RGB vs. 16 bit grayscale. Very noticable difference regardless of scanning software--48bit RGB scanning is preferred in my workflow/system going foward.
2. Silverfast Ai provides better scans consistently than Epson Scan in my workflow/system in every comparison. Very noticiable.
3. Compared three prints from each channel. Kirk, good call, green channel is the way to go with the 4990. Green is slightly better than blue.
4. Channel mixer vs. just the green channel are the same if R/B are dropped to zero in the latter. Thanks Frank/Jeremy for your feedback regarding channel mixer. At first, I was a bit apprehensive due to what I perceived as a lot of tweaking. You comments persuade me to take a closer look--
5. Green channel or channel mixer provide slightly better results than going into LAB mode and deleting (B and Alpha2 channels). Better depth overall. From a color workflow perspective, I like to apply USM filter in LAB to minimize abberations/artifacts. Not sure if this applies equally to B&W? However, I don't think going with a non-optimal b&w conversion process is preferred over workflow time.

[Frank Petronio]

Right, Green is the least noisy channel and scans of roughly neutral B&W negatives give you pretty much the same tonal range on all three channels, so you choose the Green channel and switch modes to Greyscale.

I was in Digital Camera model, sorry. Yes I use a 4990 and scan in both RGB and GS depending on time/quality rationalizations.

[DigitalDude]

Frank -- When you use the channel mixer, would you mind sharing where you set your starter RGB starter settings?

[Frank Petronio]

You don't have to use the Channel Mixer for Scanning. My bad. I was thinking about converting Digital Camera RGB into Greyscale, in which case I do use the Channel Mixer.

[OT] I haven't read up on it though. With digital camera RGB to Greyscale conversions most of the time it is something like 80% Green 20% Red, but sometimes it can be 50-50% Green and Red, or whatever so long as it adds up to 100%.

[Kirk Gittings]

You don't have to use the Channel Mixer for Scanning. My bad. I was thinking about converting Digital Camera RGB into Greyscale, in which case I do use the Channel Mixer.

[OT] I haven't read up on it though. With digital camera RGB to Greyscale conversions most of the time it is something like 80% Green 20% Red, but sometimes it can be 50-50% Green and Red, or whatever so long as it adds up to 100%.

I'm trying to keep this clear. That is for turning colored raw files into b&W right? Not for optimizing a scan of a b&w negative in RGB so as to be able to pick the best channel which maximizes sharpness and minimizes noise?

[Frank Petronio]

Yes

Please don't be so confused Kirk, I am saying that what you wrote is 100% correct and I was wrong.

Well, maybe you're not confused.... just surprised ;-)

[DigitalDude]

The previous exchange prompts an "alternative" scanning approach question. Because Silverfast is so powerful:

Would it ever make sense to optimize the scan by scanning just the green channel (during the scanning process only) in Silverfast (e.g. 48bit RGB without the R/B channels? I don't this is possible/practical, perhaps you may have tried or have some feedback?

However, as a more practical approach, any thoughts about tweaking/optimizing just the green channel (vs. doing in PS) using histogram/curves/etc. during the scanning process?

[Kirk Gittings]

I don't think that there is an option to just scan in the green channel in SF. I'm not aware of it anyway.