Scratches …. all home movies have some. There is no way around it, they can be coming from the camera (dirt int he gate); processing (poor quality lab); projection, handling, you name it…
The infamous black lines are actually the shadow of the scratch itself due to light refraction. The trick is to straighten the light rays while playing with refractive index.
Wet gate printing eliminates the refraction itself by filling in the gouges in the substrate with a fluid that shares approximately the same refractive index as the substrate. With the fluid temporarily displacing the air in the scratches and abrasions, refraction simply no longer occurs, so the defects are not reflected on the new copy.
Check our Film care & restoration page for more infos.