Dear friends

Please tell me what is Window Center & Width Explanation (0028, 1055)
and where it is used?

If I have three window width and level values like low contrast,
medium contrast and high contrast in an X Ray image, then, while
creating DICOM file, can I insert these three values to this tag using
the following order?

0028, 1055 LO ww1,wl1/ww2,wl2/ww3,wl3

Thanks and Regards