The paper presents an analysis of hologram parameters required to obtain highly selective holographic spectral filers, both reflective and transmissive. For two particular cases of spectral filters recorded and operating at the wavelengths of 488 nm and 633 nm grating parameters were analyzed as functions of the recording geometry. The spectral selectivity as a function of layer thickness was also calculated for such holograms. An overview of thick holographic materials suitable for recording of spectral selectors is presented. Experimental results on spectral filters recorded in DuPont photopolymer are discussed.