It is known that for given recording and reconstruction geometries, the wavelength of light for which a volume reflection hologram recorded in the dichromated gelatin has the highest efficiency can be adjusted by suitable preparation, sensitization, exposure, and processing of the DCG layer. Unfortunately, reliable data on these factors is very limited; thus a detailed experimental study on the relations between exposure, sensitizer concentration in the gelatin, and position of the efficiency peak has been undertaken. The sensitizer concentration in the gelatin can be adjusted by variation of its concentration in the sensitizing bath. The dependence is studied for variation of the latter in the range of 0.5% to 5%. The final sensitizer concentration in the gelatin is measured with the spectrophotometric method. The results obtained show, even for low temperature processing, that by proper combination of concentration and exposure, it is possible to create holograms with peak efficiency shifted in any (blue or red) direction by a strictly controlled amount.