Rivas splicers were the industry standard splicer throughout the early and mid twentieth century. They feature two exposed blades: one to cut the film and one to cut the tape. There are separate Rivas splicers for both sound and picture, as opposed to Emerson's guillotine splicers which can be used for both, so make sure you've got the right one before you start cutting!
Basic Concepts
Rivas splicers require much more practice and dexterity to become verse with, however they're ideal for double-perf film and, when used effectively, are much faster and cleaner than guillotine splicers.
The film is laid on the bed, with the sprocket holes being placed on the center pins. It's held taught by the spring-loaded pins on the outside. The blade in the center is used to cut the film, and the block on the right tamps down and cuts the tape to make a splice. The film should be flipped over so that both sides are taped, as Rivas splicer tape does not adhere as fast as guillotine splicer tape.
Making Cuts
Lay the film you'd like to cut down on the bed of the splicer, pushing the center pins through the sprocket holes and engaging the spring-loaded pins on the sides. Your edit mark should be in the middle of the bed, above the slim metal plates. Tamp down the film to make sure it's flush against the bed, and pull down the middle blade (NOTE: the blade is not actually very sharp. What makes the cut, similar to a guillotine splicer, is the slicing friction between the "blade" and the brown plate in the middle of the bed. If you look closely, you'll see it move slightly with the pressure of the blade).
Using the Tape
The tape on Rivas splicers must be applied manually, so don't expect to get the hang of it right away. The roll itself can be stored on the metal holder at the back.
With the incoming and outgoing shots joining in the center, sprocket holes on their respective pins, use the tamp to make sure each piece is flush against the film bed. Next, hold the tape in your left hand and pull off roughly 1" (one inch) using your right. Line the sprocket holes on the film up with the sprocket holes on the tape and hold it steadily so that the two planes (the film and the tape) remain parallel. With the tape not yet completely on the film, use your right hand to pull down the tamp, holding the tape in place against the film. Pull your left hand up and tear the tape, then place the roll back on the holder.
Tamp down the film a few times then check for air bubbles, pressing any out with your fingers. Flip the film over and repeat on the base side. Click here for a video demonstration.
Evaluating the Splice
As previously stated, effectively using Rivas splicers takes time and practice, so don't worry if your splices aren't great at first!
The ideal finished splice should line up evenly on both sides with no tape hanging off either edge. The sprocket holes should be clear, and there should be no air bubbles underneath the tape. There should also be no gap in the film, and the length of the tape needs to be roughly three frames (two in the middle, and half of a frame on both ends).
Check out Rivas splicers whenever you're using a Steenbeck if you'd like a bit of an extra challenge!