The present invention relates to a method for measuring the uniform diffuse reflectance ROBJ(λ) at least at one point on an object (30) using a device (10) comprising a means (11) capable of emitting color illuminants expressed in the form of luminous flux and an electronic color image sensor (12). The present invention also relates to a device (10) comprising a means (11) for emitting color illuminants expressed as luminous flux of colors and an electronic color image sensor (12), for measuring the uniform diffuse reflectance ROBJ(λ) at least at one point on an object (30) placed in a zone located opposite and substantially perpendicular to the said means (11) capable of emitting colors and located in the field of vision of the said electronic color image sensor (12) and being subjected to an external illuminant expressed as a constant and unknown external environmental luminous flux (40) denoted Iext(λ).