A method of manufacturing a three-dimensional object from an optically reactive starting material, comprising: - providing an optically reactive starting material in a working volume, the optically reactive starting material containing active molecules of a two-color photoinitiator; and optical treatment of the starting material to produce a three-dimensional object in the working volume by irradiating light of a first wavelength and light of a second wavelength different from the first wavelength, the light of the first wavelength and the light of the second wavelength being supplied by an illumination apparatus and the optical treatment comprising the following: a) irradiating light of the first wavelength through an aperture of an entrance pupil located upstream of an objective lens and the objective lens, the objective lens focusing light of the first wavelength into the starting material in a focusing volume in a focal point of the objective lens, so that active molecules which absorb light of the first wavelength pass into an intermediate state; b) irradiating light of the second wavelength via the entrance pupil and the objective, the objective focusing the light of the second wavelength into the starting material in the focusing volume, so that in the focusing volume, the active molecules, which are in the intermediate state and absorb the light of the second wavelength, change to a reactive state and thus trigger, in the focusing volume, a chemical reaction by which a material property of the starting material is locally modified; and c) manufacturing the three-dimensional object by repeating steps a) and b) for other focusing volumes, which are different from the focusing volume; in which light of the first wavelength and light of the second wavelength, when irradiated on the path to the focusing volume, are irradiated without spatial overlap at least when passing through the entrance pupil and when passing through the objective and with spatial overlap in the focusing volume. - providing an optically reactive starting material in a working volume, the optically reactive starting material containing active molecules of a two-color photoinitiator; and optical treatment of the starting material to produce a three-dimensional object in the working volume by irradiating light of a first wavelength and light of a second wavelength different from the first wavelength, the light of the first wavelength and the light of the second wavelength being supplied by an illumination apparatus and the optical treatment comprising the following: a) irradiating light of the first wavelength through an aperture of an entrance pupil located upstream of an objective lens and the objective lens, the objective lens focusing light of the first wavelength into the starting material in a focusing volume in a focal point of the objective lens, so that active molecules which absorb light of the first wavelength pass into an intermediate state; b) irradiating light of the second wavelength via the entrance pupil and the objective, the objective focusing the light of the second wavelength into the starting material in the focusing volume, so that in the focusing volume, the active molecules, which are in the intermediate state and absorb the light of the second wavelength, change to a reactive state and thus trigger, in the focusing volume, a chemical reaction by which a material property of the starting material is locally modified; and c) manufacturing the three-dimensional object by repeating steps a) and b) for other focusing volumes, which are different from the focusing volume; a) irradiating light of the first wavelength through an aperture of an entrance pupil located upstream of an objective lens and the objective lens, the objective lens focusing light of the first wavelength into the starting material in a focusing volume in a focal point of the objective lens, so that active molecules which absorb light of the first wavelength pass into an intermediate state; b) irradiating light of the second wavelength via the entrance pupil and the objective, the objective focusing the light of the second wavelength into the starting material in the focusing volume, so that in the focusing volume, the active molecules, which are in the intermediate state and absorb the light of the second wavelength, change to a reactive state and thus trigger, in the focusing volume, a chemical reaction by which a material property of the starting material is locally modified; and c) manufacturing the three-dimensional object by repeating steps a) and b) for other focusing volumes, which are different from the focusing volume;