Wetgate

Scratches on film are best removed with the wetgate method, an old and proven method. The film's base layer runs through the film projector closest to the lamp and the image plate. The film often gets scratches on this side. With a wetgate method, the film is moistened and the scratches are filled with a liquid that should ideally have the same refractive index as the film's acetate base. Scratches on the emulation / image side do not disappear with this method, they must be removed digitally. On the other hand, dust and dirt are removed. The scan of the film results in a significantly cleaner image, and only a small part must be removed in post-processing.

The second dust roller is removed and replaced with wetgate.
Wettex cloth is used to absorb liquid from the container.

This wetgate holds  5 ml of fluid and is designed for a 180 meter reel. It can be made larger, but will interfere with the left film reel. If requested, I can easily make a larger version for a 120 meter reel, which will hold more fluid.

Cellulose is a good material to soak up liquid with. The easiest way is to use Wettex cloth, a Swedish patented invention from 1949. It is made of cellulose and a small amount of cotton. It is also available under other brands if you can't find the original.

Demo video Wetgate

It is common to use isopropanol (IPA) for wetgate has a lower refractive index than 8 mm film (acetate). Single 8 has a polyester base that has an even higher refractive index. I chose to use white spirit*, it has a higher refractive index and. white spirit does not damage the film, there are others who have used this, it does not damage painted surfaces, it seems to be quite harmless, but smells a little more. PLA is not a good material to make containers for white spirit so use TPU instead. TPU is a rubber-like filament, similar to plastic rubber for mobile phone shells. It is waterproof and can handle white spirit / isopropanol etc.
If you still prefer isopropanol, it works quite well, but be careful it dissolves painted surfaces (spray paint) if you spill isopropanol wipe it up immediately and dry with a hairdryer.

* Different names depending on country lacknafta (Swedish) / White spirit / Mineral spirits / Lackbenzin

To avoid spills and messes, use some of this to fill the container.

Do this:
- Mount the Wetgate in place
- Add a small amount of ​White spirit
- Let the wettex cloth soak up so it becomes damp
- Add more White spirit
- Mount the film
- Keep an eye on the wettex so it does not dry
- Avoid spilling ​White spirit as it will dissolve the double-sided tape that the ​​wetgate-bracket is attached with 

Download Wetgate 3D print files

Print files with TPU 100% infill, this is to ensure the container is watertight. Other parts are printed with PLA

After printing, let the container cool and fill with white spirit, with paper underneath, wait 15 minutes to detect any leaks.

This is the locking pin, with a 3 mm nut, press the cap, it fits poorly, add a drop of superglue

The stop piece prevents the container from turning, attached with good quality double-sided tape. 

Cut out 2 pieces of the wettex cloth. These pieces are mounted from the underside of the lid. A lies against the emulation side of the film and B against the base layer.