Apparatus for measuring light scattering of a sample (S) comprising: - a light beam source (SO) which is a white light source or a light emitting diode; - means for collimating the beam and making it impinge on the sample (S) in a perpendicular direction; - at least a first light sensor (PD2) - at least one second light sensor (PD1); - at least one spatial filter (F) between the sample (S) and the at least a first light sensor (PD2) - a beam splitter or dielectric mirror (BS0) for splitting the beam in two directions after scattering by the sample (S), one direction being towards the at least one spatial filter (F) and the at least a first light sensor (PD2) and the second direction being towards the at least one second light sensor (PD1); said at least one spatial filter (F) being provided with two aligned apertures, related by the following equation:; α c = arctan D 1 + D 2 2 ⋅ L wherein α c is the cut-off angle of scattering, D1 and D2 the diameters of the apertures and L the total length of the at least one spatial filter in the direction of the beam; wherein the area of the sample (S) illuminated by the light beam has a spot diameter (Ds), the spot diameter (Ds) meeting the following relation: Ds ≥ Dc ≥ D1 where Dc is the field of view of the at least one spatial filter (F), - wherein the at least a first light sensor (PD2) is arranged to receive a beam having traversed the at least one spatial filter (F) and to measure the power of rays having scattering angles below the cut-off angle α c ; - wherein the at least one second light sensor (PD2) is arranged to measure the power representing the total range of k vectors. - a light beam source (SO) which is a white light source or a light emitting diode; - means for collimating the beam and making it impinge on the sample (S) in a perpendicular direction; - at least a first light sensor (PD2) - at least one second light sensor (PD1); - at least one spatial filter (F) between the sample (S) and the at least a first light sensor (PD2) - a beam splitter or dielectric mirror (BS0) for splitting the beam in two directions after scattering by the sample (S), one direction being towards the at least one spatial filter (F) and the at least a first light sensor (PD2) and the second direction being towards the at least one second light sensor (PD1); said at least one spatial filter (F) being provided with two aligned apertures, related by the following equation:; α c = arctan D 1 + D 2 2 ⋅ L wherein α c is the cut-off angle of scattering, D1 and D2 the diameters of the apertures and L the total length of the at least one spatial filter in the direction of the beam; wherein the area of the sample (S) illuminated by the light beam has a spot diameter (Ds), the spot diameter (Ds) meeting the following relation: Ds ≥ Dc ≥ D1 where Dc is the field of view of the at least one spatial filter (F), said at least one spatial filter (F) being provided with two aligned apertures, related by the following equation:; α c = arctan D 1 + D 2 2 ⋅ L wherein α c is the cut-off angle of scattering, D1 and D2 the diameters of the apertures and L the total length of the at least one spatial filter in the direction of the beam; wherein the area of the sample (S) illuminated by the light beam has a spot diameter (Ds), the spot diameter (Ds) meeting the following relation: Ds ≥ Dc ≥ D1 where Dc is the field of view of the at least one spatial filter (F), - wherein the at least a first light sensor (PD2) is arranged to receive a beam having traversed the at least one spatial filter (F) and to measure the power of rays having scattering angles below the cut-off angle α c ; - wherein the at least one second light sensor (PD2) is arranged to measure the power representing the total range of k vectors. <EOS>