Poor man's fluid scanning (wet scanning) with Epson V700 scanner

I bet that 90% of the people who bought the Epson V700 scanner to scan film is at least very frustrated with the so-so scan quality from 35mm films and the original Epson film holders.

There are three main reasons for this:

First, (Lack of) Flatness:

The original Epson film holder is, let's say, horrible (to avoid saying any ugly words). It's flimsy and without any structural integrity. The film is always not flat due to the lack of compressing bars between the frames.

Second, (Lack of) Focus:

The film plane with the Epson holder is never at the optimal focus. There are just two height adjustments, but it never stays at the optimal height. 

You may try to use a good quality third party film holder like the ones provided by Betterscanning.com and even use anti-newton glass to keep the film strip as flat as possible. Those film holders have several screws for proper focusing adjustment and it's very labor intensive to have all set to the proper height.

The Betterscanning holders aren't cheap but they provide a very ample fine focus adjustment and compared to the Epson holder they're much better. But there are still two problems: It's expensive, especially if you order it with the anti-Newton glass plates. And because of the extra glass, there is some contrast loss due to reflexions. The second problem is that the Digital ICE infrared dust removal works very badly with the extra anti-Newton rings glass. You must have pristinely clean films to use the Betterscanning holder (and similar ones).

Third, Too many Air to Glass interfaces:

This will always cause a contrast loss. If using the original holder, there's the scanner bed glass between the film and the scanner optics.

Too many air to glass interfaces decreases contrast and may add odd reflections. Usually, the reflexions aren't a big problem. Below, that's what happens to a light ray when it hits a glass plate: dispersion and internal and external reflections making it bounce in and between other glass surfaces.

The additional dispersion is almost certain to make the Digital ICE to fail. You may check if it still works.

The dispersion effect is much higher with anti-Newton glass because in fact, this kind of glass has one (or both) external surfaces etched to minimize the glass to film contact. The effect of this is the reduction of Newton rings. 

The internal reflectance at an air/glass interface for light rays from a point source in glass. Light rays incident at angles to normal at greater than the critical angle (here, 41° for glass to air) do not leave the material and are reflected at the glass/air interface. source: ASU 

What's fluid mounting (wet mounting) ?

It's when you use a fluid between the film strip and the glass to keep it "glued" to the glass to make it as flat as possible and also to remove one of the air to glass interfaces.

There are two main ways to do this. The first one is to use a dedicated fluid mount holder system, like the one Epson send with the V750. There are some clones on the market.

Epson fluid mount for the V750

It's basically a holder with a glass bottom and an alignment support with a printed grid.

The idea is to:

1. Put some sort of fluid over the glass
2. Place the negative over the fluid
3. Align it using the grid pattern
4. Cover the film with a transparent mylar or polyester film. You need to apply some fluid over the film, between the film and the transparent film.
5. Squeeze out any bubbles with a very soft cloth
6. Place the holder over the scanned flatbed and scan

This works well IF the focus distance between the holder and the scanner sensor is correct. It's the same focusing problem all over again and you still have a damn glass-air-glass path between the film and the scanner sensor.

The fluid mount holder must be at the proper focus distance

The holder has at least two advantages: First, it keeps the fluid out from your scanner glass. Second, it's easier to align the film. But you still have the two problems I mentioned above.

Again, the fluid mount holder is not exactly cheap.

What I'm doing is simply to fluid mount the film directly over the scanner glass. Yes, I know this may sound creepy but believe me, it's completely safe if you know how to do it properly.

The main concern is about damaging the scanner. This is simply the case to not let the fluid leak into the scanner interior. Just use the proper quantity and it will not leak.

Some people use mineral oil as a mounting fluid. Please don't do this. It's a total mess and a real pain to clean both the film and the glass. I've tested many fluids and, believe me, the best one by far is the old good Zippo Premium lighter fluid (black can). It will not attack the film emulsion neither the glass. It's very volatile and will let no residues behind. Just use the minimum quantity you can.

For the transparent film, I use those cheap transparencies used on overhead projectors.

If you're paranoid with the eventual fluid leaking inside your scanner, you can apply a thin silicone rubber sealing on the glass-plastic gap or even using adhesive tape. I use UHU's Patafix for this task.

Mounting directly to the scanner glass removes the last two problems and in my case, a great improvement in image quality.

Wet mount directly over the scanner glass
Epson V700 at 2400 dpi
Click to enlarge !