f32 at 0x12: maximum of the display ordinate range.
f32 at 0x16: minimum of the display ordinate range.
u16 at 0x00: 0x0000, 0x0001, 0x0800 or 0x1000 (file family).
u16 at 0x04: photometric mode code (1, 2 or 3 observed).
u16 at 0x08: sampling interval code (4 = 0.5 nm, 5 = 1 nm, 6 = 2 nm; 0 in some files).
u16 at 0x06: probably the scan speed code (3, 5 or 7 observed).
Fixed fields of the 120-byte header of a Shimadzu flat file. The meaning of the codes is not confirmed, so the Y axis stays labelled Absorbance.