How to Calibrate the Epson v700 Film Height Adjusters

In this tutorial I’ll be looking at how to calibrate the Epson V700 height adjusters to achieve the best scanner performance. Whilst I’ll be using an Epson V700 for this, other scanner makes, and models have adjustable height film holders. You can therefore try the same approach and tips with those.

Why Adjust the Film Height?

Before we get into how to adjust the film holder height, it helps to understand why it’s important to do this with many flatbed scanners.

Consumer grade film scanners fall into two broad categories: flatbed and dedicated film scanners. With the dedicated film scanner, the only thing you can do is scan film. These scanners tend to have a mechanism (unless you’re using a cheap one) to focus the lens onto the film.

With a flatbed scanner, you can scan film and documents and the lens is a fixed distance from the media you’re scanning. Most don’t have a way to adjust the focus. Instead they rely on changing the distance of the media from the lens by changing the height of the film holder. Additionally, because of manufacturing tolerances, the focus height for one scanner be different to another. This can be true even for the same scanner model. This is why the Epson V700 (and some other scanners) has a film holder with an adjustable height.

Height Adjustment on the Epson V700

You can adjust the height of the V700 film holder to help focus the image. You do this using the plastic shims underneath the film holder.

Here you can see one of the plastic shims and another shim in position in the Epson 35mm film holder.

Notice there’s an arrow on the surface of the shim. When it’s in position in the film holder it points to either an O or + mark. This is how you change the height of the film holder.

When the arrow points towards the O the holder is sets the film holder to a height of 3mm. If you pull the shim out to remove it, the film holder sits at a hight of 2.5mm. When you insert the shim pointing to the + mark, the film holder has a height of 3.5mm. The Epson V700 film holder therefore has a height range between 2.5mm and 3.5mm.

Now it’s time to determine the best height for the film holder.

Determining the Correct Film Height for Scanning

We’ve already mentioned that due to manufacturing tolerances, the best scanning height may differ between scanners, even of the same model. That’s why it’s important to test your scanner to find the best height.

Finding the best scanning height is relatively simple. It involves making three separate scans of a film negative or slide you know to be sharp. You make each scan using a different height setting and then compare them to find the sharpest.

When making the test scans, you must use a slide or negative that you know is sharp or it will make judging the results difficult. It’s also important to get the film as flat as possible in the holder. A bent or warped film can affect the results.

Finally, I would recommend staying within the optical resolution of the scanner if possible. Many flatbed scanners boast high resolutions but when tested, the ability of the lens to resolve fine details falls short of the claimed figures. For this reason, I recommend a scanning resolution of 1,800ppi to 2,400ppi for the testing. This will be at the top end of what most flatbed scanner can resolve.

Test Scan Results for the Epson V700

Below you’ll find three scans which I made at 1,800ppi from a section of a Fuji Velvia slide film. Each scan used a different film holder height setting. The area you can see is a small section of the slide magnified at 200%.

There’s not much difference between the three and you may not be able to see this from my screen grabs.

After looking at the scans closely on my computer I could see scan 2 (made at 3mm height) was slightly sharper than scan 1 (at 2.5mm height). Scan 2 is also slightly sharper than scan 3 (at 3.5mm height). Comparing scan 1 with scan 3, scan 3 is sharper.

The results tell me that the best height setting for my Epson film holder is 3mm. But it also tells me the optimum height is probably somewhere between 3mm and 3.5mm except the Epson holder doesn’t allow for such fine adjustment.

When the Height Falls Outside the Adjustment Range

Whilst the best height for my scanner is in its adjustment range, this isn’t always the case. If you find yourself in this position, you might benefit by using a variable height film holder from Better Scanning. These holders have a much larger range for adjustment as well as allowing a finer degree of control.

But before you dash off to spend your hard-earned money, there’s something else you can try.

By attaching small squares of masking tape to the base of your holder you can gradually raise the height. This allows you to test from the lowest height of your holder to beyond the maximum. I suggest using 3M masking tape as it has a known thickness of 0.147mm (which we can round to 0.15mm).

Now you can repeat your testing to find the optimum height and exceed the maximum height of the film holder’s adjustment.

Conclusions

Using the Epson V700 film height adjusters will make a difference to your scanner’s performance and is an important step in optimising its performance. With careful testing you should be able to determine the best height for the film holder. This may or may not be within the range of the film holder’s possible adjustment. If you think the best setting is outside the possible range, try to use the masking tape method of shimming the film holder. This will allow you to determine if it’s worth your investing in something like the Better Scanning film holder.

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