The parameter name shall be “windowCenter” for URI based mode, and “WindowCenter” for the WS mode .
Controls the luminosity of the image s as defined in PS 3.3. This parameter is OPTIONAL for the URI based mode and the WS mode “Rendered Requester” transaction . It shall not be present for other WS mode transactions. It is REQUIRED if "windowWidth" is present. This parameter shall not be present if there is a presentationUID parameter. It shall not be present if contentType is application/dicom.
The value shall be encoded as a decimal string (DS), as specified in PS 3.5.