Sandy you don't scan in 16 bit rgb, then pick the green and/or red channels and then use either or both of them to first convert to monochrome rgb to do your image editing?
Sandy you don't scan in 16 bit rgb, then pick the green and/or red channels and then use either or both of them to first convert to monochrome rgb to do your image editing?
Brian,Originally Posted by Brian K
I develop with staining developers, and one can often get better results by scanning in RGB and then evaluating the separate channels for best tonal control. I always do this with MF film, and sometimes with 5X7 and 7X17. However, scanning a negative of 12X20" in RGB at 1200 ppi will result in a file size of 1.9 gb (which takes a lot of patience to process), so unless the negative looks very difficult to control in terms of tonal values I will make the scan fo 12X20 in grayscale.
If you are developing B&W film with traditional non-staining developers there is very little reason to scan in anything other than grayscale, IMO.
Let me say that I have been doing this for several years and am still learning (guess I am a real slow learner) so I am always attentive to other ideas about what works best. So I listen a lot.
Sandy
Sandy, I don't use staining developers but I do notice a distinct difference between color channels when scanning a B&W beg in RGB. This might be due to the fact that I selenium tone all my negs to some degree. I most often use the green channel or green with a little red channel added, and almost always discard the blue channel. I find the blue channel noisier and less sharp than the other channels. From what I have heard from others this a fairly common practice.
I have not found any advantage to RGB scanning of LF and ULF B&W negatives developed in non-staining developers.
You cite common practice. Have you tested this yourself with LF and ULF negatives? If so, and you have found some advantage, perhaps you could share the results? I just don't find there is anything to gain.
Sandy
I have found noticeable differences in noise and sharpness in the RGB channels of prosumer scanners from the Epson 3200 through 750 and the Canons and Microtek 1800f, but effectively none in the scans that Ted Harris has done for me on his professional flatbed.
Thanks,
Kirk
at age 73:
"The woods are lovely, dark and deep,
But I have promises to keep,
And miles to go before I sleep,
And miles to go before I sleep"
Sandy, I don't go to the bathroom without testing first.
I haven't scanned any B&W negs larger than 4x5" with my latest scanners, but with 4x5 and 6x12cm, 6x17cm B&W negs the difference between the rgb layers is pretty obvious. I don't know about you but my B&W negs are not neutral gray they have a coloration. This might be due to the tinting that occurs with X-tol which tends to make a brownish neg, or the fact that I will slightly selenium tone all my negs for stability, or outright selenium intensify some of my negs for increased contrast. But the fact is that the 3 channels R.G and B all render a different tonality, and in some cases it is far from a subtle difference, and that the blue channel also tends to be less sharp and have more noise and more apparent grain. Maybe the lower appearance of sharpness is due to the increased grain and noise.
It is for this reason I scan rgb, and almost always dump the blue channel in the channel mixer and use a combination of green and red, mostly green.
Kirk, are you having Sandy scan your B&W negs in 16bit RGB? From what it sounds like Sandy doesn't think there's a difference unless you're scanning a stained neg. Are your B&W negs stained or developed with non staining developer? On both my Imacon and IQ3 scanners the differences between channels is very obvious. They often look like 3 different contrast/curve/brightness settings were used for each.
It is also possible to scan as Gray and then convert to RGB, this would result in rgb channels that are identical, as would scanning in rgb and then using the channel mixer to create a monchrome rgb file.
I notice in the ColorGenius software profiles for several films though they are mostly consumer 35mm brands except for Fuji 160NPS. How does one create a profile for a particular film? I suspect that some calibration target must be captured at a specified color temperature, scanned and profiled with scanner controls until optimum results are achieved. The settings are then saved to a profile. Has anyone here made their own custom film profiles?
I never said that there would not be a difference in the RGB channels. There may be a difference even with perfectly neutral film because every scene will have lesser or greater amounts of each light present, and the color of the light present will affect both negative density and contrast because of the different sensitivity of film to Red, Green and Blue light. Most films are more sensitive to Green and Blue light than to Red and that fact should be reflected in the densities of the RGB channels. Pan film is usually most sensitive to B light, and this fact also should be seen in the RGB channels.
You could choose to drop one or more of the channels if you want, and that may certainly change density and contrast more or less as if you had chosen to shoot the scene with a band cutting filter. However, in looking at a few high resolution scans of neutral tone negatives developed in non-staining developers I do not see any difference in either grain or sharpness in comparing the Blue and Green layers. And of course, dropping one or more channels of the scene is going to give you a representation unlike what you would expect with a panchromatic type film.
It is known that Xtol gives a slight stain, or at least a color that is not perfectly neutral, and it is also clear that selenium toning would change the color. If you can get better prints by scanning these negatives in RGB and then adjusting the channel, so much the better. However, neither of these conditions apply to me as I don't use Xtol and I don't tone my negatives with selenium.
A pyro stained negative will definitely give RGB layers of different contrast and density and one is free to exploit this potential if there is some advantage to doing so. However, most of my work is with 5X7 and larger negatives which already have such fine grain and sharpness in prints of moderate size that I find there is very little to gain in an RGB scan compared to a grayscale scan.
Sandy King
Sandy,
May I ask why you use a staining developer? Do you print traditionally and digitally?
Joe
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