Getting the most out of the Epson 4990

[Brian Ellis]

"as we all know the film carriers for the 4990 leave somethign to be desiredas regards film flatness and focus distance."

I guess I'm not one of the "we" because I didn't know that. What are the problems with the carriers and the focus distance? More importantly, what are the solutions?

[paulr]

"What are the problems with the carriers and the focus distance? More importantly, what are the solutions?"

the first problem is the same as with any glassless neg carrier: the film won't be flat.

the second seems to be a quality control issue with the scanners: the true plane of focus is often not where it's supposed to be.

a common solution is to wet-mount the neg or trannie onto float glass, using the same kind of fluid that drum scanner operators use, and then to use shims to place the emulsion at the focal plane (which you can find by trial and error).

there's a yahoo group dedicated to this: http://groups.yahoo.com/group/WETMOUNTING/

[Frank Petronio]

If you're like me, you'll be back to rescanning your best images over and over during their lifespan. I've scanned the same film on four or five different generations of scanners now, each time with slight improvements. Same with the Photoshop and other digital imaging tools - CS2 is so much more powerful at getting the most of my images - I cringe at the thought of opening up work I did in 1995 and usually just start over from scratch.

So, use your 4990. If you get something fantastic you can always go buy some higher end scans, or wait another couple of generations for some really amazing hardware and software.

(that said I am starting to think about wet mounting too, but not for every scan...)

[Emre Yildirim]

Ed,

What's the difference between upsizing the 2400 to 4800 and downsizing the 4800 to 2400? I don't see any difference between the scans when I upsize the 2400 scan. I'll try downsizing the 4800 scan later tonight, but as far as I can see 2400 is around the real resolution of the scanner.

[Ed Richards]

There are a couple of reasons - first, why mess with a file that is 4x the size with no added resolution? Second, you might find that the downsampled 4800 looks better than the 2400 because you get the benefit of some averaging when you downsample. Be sure to use bicubic sharper.

[Emre Yildirim]

Then I could also upsize the 2400 scan with bicubic sharper....that would have the same effect as downsizing the 4800 to 2400 using bicubic sharper, wouldn't it?

As you can see I'm trying really hard to find a reason not to mess with huge 4800 dpi files

[Ed Richards]

> that would have the same effect as downsizing the 4800 to 2400 using bicubic sharper, wouldn't it?

Nope. That takes the same noise and multiplies it by four.:-)

> As you can see I'm trying really hard to find a reason not to mess with huge 4800 dpi files

Then get Vuescan. It will scan and downsample in one pass, so you never need to mess with 4800 DPI files. If you are working color, and are not running a high end mac with lots of gigs of ram or Win64, you will not be able to downsample 4800 DPI files without locking up the computer on a regular basis. Then Vuescan is essential, because Silverfast will not downsample - it just reduces the resolution when you set it to reduce the file size, or at least it did with the version around this summer.

[Emre Yildirim]

Ed,

I really appreciate your advice on this. I'm now using Vuescan. I set the scan resolution to 2400 dpi and set "number of samples" to 8. The files are signigicanly smaller in size (no more 1GB files in Photoshop). Is this the best way to do it? I think I'm getting a little confused by the downsample/oversample lingo

Is this the best way to get the least noise/highest image quality, or should I scan at 4800 in Vuescan, and do multiple samples? At this point I'm a little confused - I always thought a straight 4800 scan would produce more noise than a straight 2400 scan (and both have the same amount of detail).

[paulr]

" I set the scan resolution to 2400 dpi and set "number of samples" to 8"

not quite ... set the resolution to 4800, and in 'output' set 'tif file reduction' to 2.

if you set the resolution to 2400, it's just like scanning at 2400 in epson scan: the scanner throws out every other scan line and every other pixel. set to 4800 with tif file reduction, it samples the file down by averaging every block of 4 pixels. this is where the noise reduction comes from--noise is randomly distributed, so the chances are most blocks of 4 pixels will have no more than a single pixel corrupted by it. downsampling averages most of the noise away.

see how this works first, and then see if you can see a difference by adding samples.

[mark blackman]

I have scanned 10x8 colour film on the 4990, and had a print made that was 79" on the long size. This was on a Durst Lamdba printer at 400 dpi. I scanned at 2400. As I specifically wanted people to view this up close, I was worried about the final image. To me, it looks ok.