Frank Churchill's hair changes length in the scenes when he says goodbye to Emma - shorter when he arrives and longer when he leaves.
Mr. Knightly's hairstyle and collar change during his proposal to Emma.
During Mr. Knightley's proposal scene, Emma's hair changes. At first, the curls are quite close to her forehead, by the end of the scene, they are all the way back on her crown.
(at around 18 mins) When Emma draws a portrait of miss Smith, Emma doesn't wear earrings. However after Mr Knightly joins, Emma is seen with her earrings on.
As Emma and Knightly are leaving the church, Jane Fairfax takes Frank Churchill's arm twice.
Harriet runs her fingers along a harp and the sound that is heard is a perfect chord going up a scale, fitting in perfectly with the music that is being played. In reality, it would be virtually impossible to pluck a perfect chord when you run your fingers casually along the strings, and secondly any sound made would be going *down* scale, since she was dragging her fingers that way down the strings.
Emma plays and sings the song "Silent Worship". Although it's based on an aria from George Frideric Handel's opera "Tolomeo", the version in the film was arranged by Arthur Somervell in 1928.
Emma's painting is held to the board with what appears to be masking tape.