With the advancement in paint and
coating technology, more than just measuring gloss; some automotive
manufacturer shifted on measuring other parameters more than just gloss. As
well all known, Glossmeter measures a specular reflection gloss of a surface.
The unit we derived from a glossmeter is GU (Gloss Units) It is a scaling based
on a highly polished reference black tile or glass standard with a derived
refractive index specular reflective gloss at a defined angle. That’s why Konica Minolta Sensing tapped the
expertise of Rhopoint Instruments (UK) in providing a portable and clever
instrument which can provide other parameters to be measured in paint, coating
and surfaces more than just measuring gloss. These parameters include: DOI, RIQ
and Haze. Talking about these 3 other paramters defined and explained at the
website of Rhopoint Instruments:
“DOI (Distinct of Image) – Distinctness of Image is, as the name implies a function of the sharpness of a reflected image in a coating surface.
Two surfaces finished with similar coatings may exhibit identical gloss values but visually the quality of one coating can be seen to be very poor. Upon closer inspection the visually substandard poor coating has a highly textured dimpled appearance known as “orange peel”. When a reflected object is viewed in such a coating the image becomes fuzzy and distorted.
RIQ (Reflective Image Quality) – Reflected Image Quality is a new measurement developed by Rhopoint Instruments to provide greater sensitivity when evaluating highly reflective coatings and the specular / diffuse element of lower gloss materials.
Two highly reflective surfaces that have very small changes in orange peel or texture will show very little or no change in DOI due to the way that it is calculated, but will appear quite different visually.
By reducing the sensing distance around the specular angle and measuring the reflected light and distortion around it, a much higher resolution response is achieved with greater linearity, more in line with the visual experience.
Haze – The term “Haze” defines the milky halo or bloom observed visually on high gloss surfaces.
Surface haze can be problematic in most coating applications including automotive manufacture, powder coatings and other high gloss coatings. It can be attributed to a number of causes including incompatible materials in a formulation, poor dispersion and problems encountered during drying/curing/stoving.
Coatings without haze can be seen to
have a deep reflection and have high reflective contrast. Those with haze
exhibit a slight “milky” finish which can be seen over the highly glossy
Haze is caused by
microscopic surface texture which diffuses light adjacent to the main component
of the reflected light.” -Rhopoint Instruments Uk
Rhopoint IQ-S considered as the ultimate glossmeter upgrade as it can measure parameters more than just a simple glossmeter can measure.