The Rhopoint IQ-S measures
20/60/85° Gloss • Haze • Distinctness of image • Rspec • Goniophotometric curves
A measurement proportional to the amount of light reflected specularly from a surface.
Geometry: For best results the correct measurement geometry should be chosen based on the reflectance of the material: Matt Finish 85°, Mid Gloss 60°, High Gloss and Metallics 20°.
Measurement Unit: GU
The peak gloss value over a very narrow angle.
Usage – RSPEC is very sensitive to small changes in texture and is used to identify subtle differences in surface smoothness.
Measurement Unit: GU
An optical effect caused by microscopic textures or residue on a surface.
Visible Symptoms: milky finish apparent on surface, loss of reflected contrast, halos and patterns can be seen around reflections of high intensity light sources on high gloss and metallic samples/mirrors.
Causes: Poor dispersion, raw material incompatibility, additive migration, vehicle quality, stoving/drying/curing conditions, polishing marks, fine scrat¬ches, ageing, oxidisation, poor cleanliness/surface residue.
Measurement Unit: LogHU
DISTINCTNESS OF IMAGE
A measure of how clearly a reflected image will appear in a reflective surface.
Symptoms of poor DOI: Orange peel, brush marks, waviness or other structures visible on the surface, reflected images are distorted.
Causes: application problems, incorrect coating flow, coating viscosity too high/low, sag or flow of coating before curing, incorrect particle size/distribution, overspray, improper flash/recoat time, inter coat compatibility, incorrect cure times and cure temperature.
Measurement Scale: 0-100, with 100 being a perfect smooth surface.
REFLECTED IMAGE QUALITY (RIQ)
Like the DOI the RIQ value describes the quality of a surface in terms of how clearly visible an image is reflected.
Unlike the DOI the RIQ uses a much larger resolution that results in a much better correlation to the visual perception of the human eye. This is of a very high importance for high quality surfaces like e.g. car coatings.
Measurement Scale: 0-100, with 100 being a perfect smooth surface
The instrument displays surface reflectance profiles 17-23° (larger range with software).
The shape of the curve describes how the light has interacted with the surface.
Sharp curves close to the specular direction indicate smooth highly reflective surfaces.
An on screen goniophotometric profile shows the distribution of the reflected light.
Different textures and distortions produce identifiably shaped profiles depending on their size and frequency. Full goniophotometric information can be downloaded to PC for further analysis and comparison, without the need for interface software.