Conventional Glossmeter versus the Novo Gloss IQ
A conventional glossmeter is widely used to assess the visual quality of test panels and product surfaces; however the human eye can see certain surface defects that are not detected with a standard gloss meter. This is a particular problem where finishes are given high gloss values but rated by observers as having a poor appearance.
The reason for differences between observed quality and measured gloss is because light entering a glossmeteris recorded as one value without the detection of variation. In the human eye the reflected image activates a compact array of light sensors known as cones, the detailed signal from these cones allows the eye to see subtle textures on a surface that are not recorded with a glossmeter.
The Novo-Gloss IQ, with its array of light sensors mimics the effect of reflected light in the human eye. More detailed information from this instrument allows the user to measure and control surface defects that are undetectable with a standard glossmeter.
A crucial factor in assessing the appearance of any manufactured product is the "glossiness" of its finish.
Gloss finishes are often used to make products visually appealing. Highly reflective, extremely smooth finishes are used to enhance the aesthetics of cars, luxury yachts and high end consumer electronics. Matt finishes are used for contrast furniture and architectural features.
The Novo-Gloss IQ measures standard gloss within existing standards, and uses new technology to examine in more detail the distribution of light around the specular angle. The Novo Gloss IQ provides goniophotometric profiles, gloss, haze and distinctness of image values "DOI " (orange peel) which can be used to assess the visual qualities of a surface.
Novo Gloss I.Q. Screen showing Goniophotometric profiles, Gloss, Haze, DOI
As well as assessing the visual impact of a surface, the Novo-Gloss IQ can also be used to identify problems with coating formulation and application.
Coating problems such as dry spray, orange peel, poorly dispersed or flocculated pigments, micro bubbles, resin incompatibilities and additive migration all result in reduced DOI, Haze or gloss values and therefore can be measured with this instrument.
Each measurement consists of a 256 point profile of the reflected light. Using this information the instrument calculates Gloss, Rspec, Haze (HU or HULOG) and Distinctness of image values. These values are used to assess the visual impact and reflective quality of many coated, painted and polished surfaces.
There are several factors that influence the gloss and appearance quality of a coating:
- The chemical composition of the coating/topcoat/varnish vehicle, the refractive index of this component largely determines how light is reflected from the surface.
- The size and frequency of structures on the surface, these can be deliberate in the case of matting additives which scatter light, or unintentional and unwanted such as additive bloom, orange peel, reticulation etc.
- Uneven substrates may cause texturing to the coating surface. For transparent coatings the reflective nature of the substrate is also important.
- Metallic and Effect Pigments, the size, distribution and alignment of these larger size particles have an effect on the reflective characteristics of a coating.
By measuring Gloss, Haze and DOI, the Novo-Gloss IQ quantifies the visual impact of a product and the nature and frequency of textures on its surface. Most painted and coated objects have some degree of surface texture which impacts their visual appearance. These textures can be described by their size and the visual effect they have on the paint surface or the quality of a reflected image. The smallest textures (< 0.01mm) result in gloss reduction, the largest can result in visible ripples on the coated surface (> 1mm ). The Novo-Gloss IQ is sensitive to surface structures up to 10mm in length.