Scanning in gray scale vs RBG

[neilsphoto]

Hi all

A while back I found a strange problem with what I now believe to be white pixels in a line across frames of film I scanned. I had never had these before and I've used this combo for years w/o any problem like this.

I scan mostly TX and TMZ 3200.

Minolta 5400 scanner, Vuescan latest version (though older versions did it too) and a Mac running 10.4.11. I've used the 5400 for years but use it alot less since i went to the darkside.

Out of frustration I tried Silverfast and had no streaks/lines.

Back to Vuescan today I set everything back to default and the lines disappeared. One by one I changed my settings back to what I had been doing for years. I found the setting that made the lines.

When Vuescan is set to B&W neg, 48bit color I get the lines. If I scan as 16 bit B&W I don't. If I scan in 24bit color I don't. If I scan as a color neg 48bit color I don't. Why this does is now I have no idea.

In the end I set the profile to "gray gamma 2.2" for printing with my 2200 and Quad Tone RIP.

So do I really gain anything scanning as RGB color 48bit vs 16bit gray scale? I just scanned a neg as color 48 bit and again as B&W 16bit B&W.

The resulting images were different. More contrast in the "color" version but a print, straight out of the scanner to CS3 from teh B&W version was very good.

Opinions on 48 vs 16 please.

Neil

[Chriscrawfordphoto]

Did you have infrared cleaning turned on? That doesn't work on black and white negs, and produces the spotting you mentioned. The default in viewscan is for that to be off, so thats why you got rid of the problems. Scanning in color only makes a bigger file, the quality should be identical if its a BW neg. Note that IR-clean DOES work fine on C-41 black and white films....they are basically color negs with only one color...grey. They use dyes instead of silver to form the image, and the silver interferes with the infrared clean.

[neilsphoto]

No, no ICE. I've never used it. I don't know why the limes started showing. I'm not so sure I'm going to pursue why either.

At this point I scan so little as long as I get a good scan in RGB or Gray 16bit I'm OK.

For some reason I thought I'd read that you must scan in RGB for the the best file, to have the most info even if it is a B&W image.

When I print with QTR I can print in QTR RGB or QTR gray profiles. Prints look the same either way.

I guess as long as I am working in 16 bit I have more info during adjustments than 8 bit right?

Neil

[amateriat]

I scan all my conventional b/w film in 16-bit grey (Minolta 5400 I). Haven't seen any sort of improvement scanning in RGB. With chromogenics, it's a toss-up; since it seems I can use IR cleaning in 16-bit grey mode (VueScan, of course), I haven't felt the need to work otherwise.

Originally Posted by neilsphoto

I guess as long as I am working in 16 bit I have more info during adjustments than 8 bit right?

Neil

Right: adjustments should ideally be done in 16-bit.

This reminds me of what has been a somewhat controversial issue in some circles: while most seem to agree that 8-bit files are perfectly adequate for color printing, the jury seems to be out in regard to b/w printing, and after some experimenting on my own, I'm somewhat inclined to agree with those who feel b/w printing from a 16-bit file yields somewhat better quality. Whether that extra bit of quality output is worth dealing with larger files is, perhaps, subjective, but I do notice the difference.




- Barrett

[JPSuisse]

Hi there

I suspect that the qualities of each types of scans (color or b/w) depends on the hardware and software used. Therefore, no general answer is possible. Just trial and error.

In the end, the scanner has an RGB sensor, and something is going to have to put that together as grey. In a perfect world, all software should produce the same greys. But that doesn't seem to be the case.

Cheers, JP

[jbh]

I got a similar weirdness with my 5400 and Vuescan recently; a reboot fixed it. Nothing else changed and it hasn't returned. The only other thing is that I hadn't used the scanner in several months.

-jbh-

[neilsphoto]

The whole is odd and frustrating, this whole it used to do this but now it does that thing. Plus I use it so seldom now with almost everything being digital capture. I do have tons of negs I may want to scan and print and I have a real itch to shoot some film also.

It does seem that all the Vuescan upgrades don't always work 100%. For instance auto save the scan? Won't do it. Just won't and Hamrick doesn't know why. I will always get a window after scanning I have to click "OK" on to save the scan to the HD it is going to. Always worked auto and now it doesn't.

So in the end I guess I'm a 16bit greyscale guy. I can't see any difference in print so I guess that's where I am with whole thing.

Neil

[Pherdinand]

Unless you mess around with the r,g,b channels, there should be no final difference in scanning in black and white 16-bit and rgb 48-bit.
It could happen though, that in one of the r,g,b channels your scanner works better. This is possible to check just by scanning in flat 48 bit rgb a black and white image, and switching on the channels one by one, off the other two, in photoshop.