ICCSTANDARDOBSERVER

typedef enum
{ 
    StdObsUnknown = 0x00000000L, /* Unknown */
    StdObs1931TwoDegrees = 0x00000001L, /* 2 deg */
    StdObs1964TenDegrees  = 0x00000002L /* 10 deg */
} ICCSTANDARDOBSERVER; 

This type is used within the ICC_MEASUREMENT structure to indicate the standard observer.