Reflection film, windshield glass, and head-up display system

A reflection film comprising:

• a selective reflection layer formed of a cholesteric liquid crystal layer with a cholesteric liquid crystalline phase immobilized,
• wherein the selective reflection layer satisfies all of requirements (i) to (iii),
• (i) in a wavelength range of 400 nm or more and less than 500 nm, a maximum value of a natural light reflectivity is 10% to 25%, a difference between a greatest maximum value and a smallest minimum value of the natural light reflectivity is 3% or more, and a total value of wavelength bandwidths in a region where a reflectivity is higher than an average value of the maximum value and the minimum value of the natural light reflectivity is 20 nm to 80 nm,
• (ii) in a wavelength range of 500 nm or more and less than 600 nm, a maximum value of a natural light reflectivity is 10% to 25%, a difference between a greatest maximum value and a smallest minimum value of the natural light reflectivity is 3% or more, and a total value of wavelength bandwidths in a region where a reflectivity is higher than an average value of the maximum value and the minimum value of the natural light reflectivity is 20 nm to 80 nm, and
• (iii) in a wavelength range of 600 nm or more and 800 nm or less, a maximum value of a natural light reflectivity is 10% to 25%, and a total value of wavelength bandwidths in a region where a reflectivity is higher than an average value of the maximum value and the minimum value of the natural light reflectivity is 120 nm or more.