Rhopoint ID

The Rhopoint ID is an instrument that can measure what the eye can see. It quantifies the see-through qualities of materials in a method that can be matched to real world conditions with results highly correlated to customer perception. It also measures small sample sizes that cannot be measured with a traditional haze meter. The unique Rhopoint ID method fully characterises the transparency of a material in a single measurement.

Measurement parameters

Haze

• Haze is measured directly by evaluating contrast of black and white areas on graticule
• Measurements made with the Rhopoint ID are fully comparable with those made on an ASTM D1003 haze meter
• Automatically operates when ASTM Haze platen (8 mm thickness) is placed in position on instrument between the graticule and a sample
• Factory calibrated to ASTM standards for a quantitative match.

Sharpness

Sharpness quantifies the loss of perceived detail for objects viewed through a material.

Anisotropic Sharpness (Only available with Rhopoint ID-L version)

• The Rhopoint ID is the only instrument that can measure directional effects in materials using the ID laboratory analysis software.
• The images to the right show the visual impact of different ID Sharpness (S) values in vertical and horizontal directions.
• Measuring directional effects can be used in advanced optical quality control and for adjusting processing parameters to obtain optimal transparency.

Clarity

• Quantifies the blurriness of an object when viewed through a material, results are proportionate with Sharpness, but the measurement scale is compressed and the measurement resolution is reduced.
• Clarity is a scale used by traditional haze and clarity meters. When measured using the 8mm adaptor plate, Rhopoint ID Clarity data conforms to specifications written for these meters.
• Inter-instrument Clarity agreement between Rhopoint ID and traditional sphere instruments for commercial plastic films (<1000μm) is typically <0.4% C (SD).
• Inter-instrument Clarity agreement between traditional sphere instruments and Rhopoint ID for thick transparent plastic materials (<6mm) is typically <0.5% C (SD).

Waviness

• Waviness measures the visible distortion of the ID graticule edges through the material. W is the standard deviation of the edge deformation in μm.
• Waviness homogeneity is assessed by comparing W (average waviness) with WH (horizontal waviness) and Wv (vertical waviness) using Rhopoint ID software available with the Rhopoint ID-L version.

Distance Dependent Haze

• Direct measurement of haze from transmission image contrast
• Measured in contact or at user-defined distance between material and object (0–40 mm)
• Measures distance dependence on the same scale as ASTM Haze
• Direct measurement of transparency via contrast of black and white areas on target graticule
• Measure and understand distance dependent haze

Visible Transmittance

• Rhopoint Transmittance (TID) quantifies the amount of light passing through the material and reaching the camera/eye of the observer
• This measurement describes the brightness/ luminosity of the viewed object and is correlated to how one perceives the quality of the material.

Benefits of the ID

• Comprehensive quantitative evaluation of transparency (Haze, Sharpness, Transmittance)
• Full correlation with visual perception, including effects of air gap distance and anisotropy
• On-demand ASTM D1003-equivalent haze data
• Ability to identify local optical defects
• Suitable for plastic films and sheets, glasses, coatings and liquids with thickness up to 35mm
• Low cost compared with conventional instruments
• Robust design, with small weight and footprint
• Rapid data acquisition; no moving parts – suitable for (in-line) process and quality control
• Intuitive built-in software for data management and image analysis