Assume you want to play a D one octave higher than the D-string. That is the 3rd finger on the A-string. So you put a tape there. Now your student puts the 3rd finger down on the tape and play, then lift the finger, put it down again and play. But the second time the finger was off by one milimeter compared with the first time. Therefore the note will be different, but the student can argue that the finger was placed on the tape in both cases. Thus you can conclude that the tape is only a guideline you must use the ear and listen.

Now how do you place that tape for the 3rd finger? You place it so it fits a note exactly one octave above the D-string. Since violin players usually tune the D-string in an actually perfect fifth relative to A and the A is tuned to the A on the piano the D-string will be a tad lower than the D on the piano.

In case you tune all the open strings so they fit the notes on the piano you still need to play the 3rd finger mark on A so it fits the note exactly one octave above the string, but in this case the result will be ET.

Conclusion is that you must place the tape in order to get the best resonance with the open strings. How it sounds will depend on how you tune the violin. But since both the tunings I have mentioned require the 3rd finger on A to be exactly one octave above the D-string the tape is likely to be put on the same place in both cases.

Use your ear when placing the tape and use your ear when playing.

Assume you want to play a D one octave higher than the D-string. That is the 3rd finger on the A-string. So you put a tape there. Now your student puts the 3rd finger down on the tape and play, then lift the finger, put it down again and play. But the second time the finger was off by one milimeter compared with the first time. Therefore the note will be different, but the student can argue that the finger was placed on the tape in both cases. Thus you can conclude that the tape is only a guideline you must use the ear and listen.

Now how do you place that tape for the 3rd finger? You place it so it fits a note exactly one octave above the D-string. Since violin players usually tune the D-string in an actually perfect fifth relative to A and the A is tuned to the A on the piano the D-string will be a tad lower than the D on the piano.

In case you tune all the open strings so they fit the notes on the piano you still need to place the 3rd finger mark on A so it fits the note exactly one octave above the D-string, but in this case the result will be ET.

Conclusion is that you must place the tape in order to get the best resonance with the open strings. How it sounds will depend on how you tune the violin.

Use your ear when placing the tape and use your ear when playing.

Assume you want to play a D one octave higher than the D-string. That is the 3rd finger on the A-string. So you put a tape there. Now your student puts the 3rd finger down on the tape and play, then lift the finger, put it down again and play. But the second time the finger was off by one milimeter compared with the first time. Therefore the note will be different, but the student can argue that the finger was placed on the tape in both cases. Thus you can conclude that the tape is only a guideline you must use the ear and listen.

Now how do you place that tape for the 3rd finger? You place it so it fits a note exactly one octave above the D-string. Since violin players usually tune the D-string in an actually perfect fifth relative to A and the A is tuned to the A on the piano the D-string will be a tad lower than the D on the piano.

In case you tune all the open strings so they fit the notes on the piano you still need to play the 3rd finger mark on A so it fits the note exactly one octave above the string, but in this case result will be ET.

Conclusion is that you must place the tape in order to get the best resonance with the open strings. How it sounds will depend on how you tune the violin. But since both the tunings I have mentioned require the 3rd finger on A to be exactly one octave above the D-string the tape is likely to be put on the same place in both cases.

Use your ear when placing the tape and use your ear when playing.

Assume you want to play a D one octave higher than the D-string. That is the 3rd finger on the A-string. So you put a tape there. Now your student puts the 3rd finger down on the tape and play, then lift the finger, put it down again and play. But the second time the finger was off by one milimeter compared with the first time. Therefore the note will be different, but the student can argue that the finger was placed on the tape in both cases. Thus you can conclude that the tape is only a guideline you must use the ear and listen.

Now how do you place that tape for the 3rd finger? You place it so it fits a note exactly one octave above the D-string. Since violin players usually tune the D-string in an actually perfect fifth relative to A and the A is tuned to the A on the piano the D-string will be a tad lower than the D on the piano.

In case you tune all the open strings so they fit the notes on the piano you still need to play the 3rd finger mark on A so it fits the note exactly one octave above the string, but in this case the result will be ET.

Conclusion is that you must place the tape in order to get the best resonance with the open strings. How it sounds will depend on how you tune the violin. But since both the tunings I have mentioned require the 3rd finger on A to be exactly one octave above the D-string the tape is likely to be put on the same place in both cases.

Use your ear when placing the tape and use your ear when playing.