Generally, the B foot flute membrane is taken from the inner membrane of the reed. Because the membrane is thin, only about the size of a thumb, it is easy to break, so the membrane must be very patient, and the technique must be meticulous to prevent the membrane from breaking or sticking crookedly. The B foot flute film has a great influence on the resonance tone of the flute, so mastering the B flute filming technique is a necessary practice for beginners.

When applying B foot flute film, first cut out a square B flute film, make the fiber of the B foot flute film parallel and overlap with the fiber of the flute, and then apply donkey-hide gelatin soaked in water around the film hole, pinch it with the thumb and index finger of your left and right hands. Hold both sides of the flute membrane, pull out the wrinkles that are perpendicular to the fiber lines of the reed membrane, and then slowly press and paste it down, adjust it evenly and hold it down for a while to complete. The storage of the flute film should be protected from moisture and sun protection. When the flute film turns yellow, becomes old, or loses elasticity, it should be replaced.
First use a needle to cut the film in pairs, cut a small rectangular piece, and then gently knead it into a small ball with the thumb and index fingers of the right hand. Twist the membrane into many fine wrinkles, and then gently unfold it. After the membrane returns to its original shape, use the thumbs and four fingers of both hands to gently stretch it forward, backward, left and right several times. This not only prevents the B foot flute film from becoming loose after being pasted, but also makes the B foot flute film more uniform. Then use donkey-hide glue (donkey skin glue) dipped in some water (or garlic juice can also be used), rub around the membrane hole, make the flute pattern and B foot flute pattern parallel to the direction of the flute membrane.
In addition, the pattern on the B foot flute should not be too big. If it is too big, the sound will be rusty. Don't stick the B foot flute membrane too tightly or loosely. If it is too tight, there will be no clear and loud sound. If it is too loose, the sound will be hissing and unpleasant. Solution: When it is too loose, you can use your finger pad to press on both sides and gently pull it; when it is too tight, you can use your finger pad to press the center of the flute membrane, but do not stain the flute membrane, let alone water. B flute film will get old if it gets wet, and the sound will be unpleasant. In short, filming is a very meticulous and patient work. High-quality flute film, if the filming technology is not good; it is impossible to achieve the ideal resonance effect. Therefore, mastering the filming technique is a compulsory course for beginners to learn flute.