  The composition and characteristics of a GRISM gained by refractive index
matching between a refractive index modulation type HDG and a prism is
investigated, the HDG being built by processing silver halide emulsion with
halide vapor. The GRISM has been stable under external influences like humidity
or ultraviolet light exposure. The mercury atomic spectrum obtained by a GRISM
based on a HDG with a spatial frequency of 600mm-1 shows yellow dual lines with
the wavelength difference of 2.1nm sufficiently separated.
