Epson V700 Issue

[Keith S. Walklet]

This was a double post...see the next post.

[Keith S. Walklet]

This thread seems to be running parallel to a couple of others with related topics. Since you are discussing the merits of various mounting methods and holders, I thought it would be useful to share these three jpegs.

The scanned image is a small piece of Leigh Perry's collaborative scanning 4x5 Velvia transparency. These were all scanned with the V-750 at 6400spi, downsampled to 2400dpi in Photoshop and sharpened 400-1.0

The first comparison L-R:
-Plain vanilla Epson 4x5 holder
-Wet mounting directly to the platen
-Wet mounting with the Epson mounting station.

The first two methods employ the lower resolution lens that is focused on the platen glass. The last engages the higher resolution lens.

The second set compares:
-Epson wet mounting station
-Wet mounting on a 3/16" piece of plex
- Wet mounting on a 3/16" piece of plex with the addition of a layer of diffuse mylar.

The third jpeg compares:
-Wet mounted 3/16" plex
-Wet mounted 3/16" plexwith diffuse mylar
-Wet mounted 3/16" plexwith diffuse mylar elevated 1/32" above the film.

As it happens, these files show a progressively better result from left to right, with IMO, the best result having been achieved with the 3/16" plex and elevated diffuse mylar.

I use the KAMI fluid and mylar from Aztek for wet-mounting.

[David Luttmann]

Keith, could you describe your wet mounting to platen process?

[Keith S. Walklet]

Here you go Dave:

With a strong light shining on the scanner bed at a sharp angle so I can see dust

1. Wipe platen with microfiber cloth
2. A squirt of Kami in the center of the bed
3. A 5x7" piece of 3/16" Plexiglas placed in the center of the bed on top of the fluid
4. Push bubbles out to sides using the microfiber cloth and soak up excess fluid
5. Make sure no dust is on top of the plex
6. A squirt of Kami on the plex
7. Place the transparency on the Kami (reverse read oriented)
8. Another squirt of Kami
9. 1/2 of a sheet of optical mylar placed on top of the fluid and transparency with an edge hanging off the plex for easy lifting or removal
11. Move bubbles out and make sure there is no dust
10. A windowmat (my old Saphir 4x5 holder works) placed on top of the mylar to hold the diffuse mylar away from the optical mylar's surface

Ready to roll...

[Keith S. Walklet]

Another couple comparisons with Leigh's transparency.

This time my old 4870 vs. the V750.

The 4870 files have a couple of disadvantages with regard to software. I only have the Silverfast SE for that scanner, so the colorspace choice was not 48bit HDR, and the resolution was only 4800spi, downsampled to 2400dpi in Photoshop whereas the V-750 sample was scanned at 6400spi and downsampled to 2400dpi. All the files were sharpened 400-1.0 as with the previous comparisons.

The 4870 files are clearly much noisier, partly because they were scanned in a single pass, where the V750 was done in two passes.

Still, the wet-mounted 4870 is sharper than the dry-mounted V-750 in its stock holder. The overall quality would be even better if the software was equal, I am certain. But, once one starts to work the advantages of the V-750 (wet mounting, high magnification lens, full software package) illustrated in earlier jpegs, it easily outpaces the 4870.


From left to right:

4870 with stock Epson holder
4870 wet mounted directly to the platen
V750 stock Epson holder

[Jon Middleton]

Thanks, Keith. Nothing would make me happier than to be able to fluid mount my film and get superior scans. It just didn't happen in my test, and I don't think it was due to a lack of experience. Mineral oil doesn't evaporate, so I was able to take my time doing the setup, and am pretty sure everything was correct. No discernible difference, and it doesn't look to me like Kami fluid will change the result.

Theoretically, the main advantage of fluid mounting is to maintain film flatness. I guess that begs the question, how flat does the film need to be? How much variability is allowable? In other words, what is the DOF of the scanner lens? So long as your film is within optimal range of focus for the scanner's lens, it's not clear to me that fluid mounting adds much.

Another question regarding your method of fluid mounting. Why not mount the way Doug does it, ie, film down? That way you can experiment with height, and are not limited by the thickness of your plex. You could make different thickness spacers to vary the height off the platen.

Below are some scans of a 4x5 transparency taken of the Grand Canyon of the Yellowstone. All were scanned at 48 bit/2400 DPI. 4800 DPI yielded files of 2.2GB, way too big. The first is in the standard film holder, no sharpening. The second is in oil, on the platen, no sharpening. The last is in the film holder, sharpened. It looks a bit harsh, but it's a 100% crop. Smaller enlargements just look sharp, not artificial:







So, the question is, is fluid mounting worth it?

[Keith S. Walklet]

Jon, I think the jpegs I've uploaded so far are probably too small to show the difference in quality. I'll separate the images out so that they can be seen at 100%.

At that level of quality, the differences are obvious. Is wet mounting worth it? Absolutely.

I actually tried wet-mounting my film underneath the Epson Wet Mount holder in a manner similar to Doug's approach, which in my case required taping the edges of the mylar to the glass (which may have been unnecessary, but created a mess that was a pain to clean up). In that round of tests, I wasn't using Leigh's transparency, but one of my own. Since you've asked, I'll probably give it another shot with Leigh's transparency.

For the same reason that Doug advocates mounting underneath, I felt it would be advantageous to have the scan completely enclosed in fluid. Less chance for refraction and flare. That meant finding a piece of plex that was thick enough to duplicate the optimized height that the film was scanned at. I experimented with 1/16" plex, 1/8", and found that the ideal height was a combination of both thicknesses: 3/16".

For certain, the adjustable height mechanism Doug has crafted is far superior than the Epson holders, but I could see no way to incorporate "adjustable" into a process that required a continuous fluid envelope, unless the platen itself was adjustable.

The examples you have posted appear not to have taken advantage of the high resolution lens that the scanner uses for "with film holder" scans. There is a difference in quality there, too. So let me post a few 100% examples.

[Jon Middleton]

I think the two scans with the film holder actually used the higher resolution lens, as it is selected when you choose the document type.

Here's an idea. If the ideal height is 3/16" for your scanner, just mount Leigh's film on glass, put mylar over the top, taping it around the edges (I used blue painter's tape, no mess), but leaving the corners open so you can sqeeze out bubbles and fluid, then flip it over onto the scanner, supporting the corners with 3/16" spacers. That allows you to mount off the platen, avoiding the cleanup. It also eliminates the platen/plex interface. As far as adjustable, just make spacers of different thicknesses. Not a big deal. Once you settle on the optimum height, you're done.

It's interesting that your optimal height is 3/16", as that's 4.8mm by my math. How high was the film in your previous test with the Epson FMA? My optimal height appears to be 3.5mm, though I have only tried higher a couple of times.

[Keith S. Walklet]

OK, here are three.

The first is wet mounted with Kami directly to the bed. Low res lens.
The second is wet mounted using the Epson holder. High res lens.
The third is wet mounted to 3/16" plex that is wet mounted to the bed. High res lens.

[Jon Middleton]

Another question. Is the high rez lens sharper than the low rez lens when scanning at 2400 DPI?