11 Aug Material Gloss Specifications
There are times when we are confused about a specific gloss/matte finishing, and wonder what it means. Some picky designers go to the extent of providing the range of glossiness (sheen or light reflectivity), which can be measured using special equipment such as the Minolta Glossmeter. Such instrument can be used during product acceptance at the factory. The article provides a recommendation of the range based on our experience over the past 10 years.
Firstly the material needs to have a smooth surface for reflectivity. For mirror effects, the surface needs to be perfectly smooth for a distortion free reflection. Even surfaces such as polished steel or SS 304 can have almost close to mirror effects if the manufacturer can ensure no distortion of the surfaces. In general, designers could specify the following sheen.
Secondly, you will need an adequately lighted space to check the sheen of any panel. You need to have “reflection” to check the sheen on any surface.
Thirdly, our guide below is based on experience with visual inspection (naked eye). If necessary, please use a calibrated, professional glossmeter to verify. The recommendations below are only for general guide. The percentage of sheen should be based on the Gloss Units (GU) of gloss meters.
This standard is used to establish an upper point calibration of 100 with the lower end point established at zero on a perfectly matt surface. This scaling is suitable for most non-metallic coatings and materials (paints and plastics) as they generally fall within this range.
Gloss Levels (Sheen)
- High Gloss
- Low Gloss
1. Hight Gloss, approx. 85 – 100% sheen: At the top end, there is the high gloss to mirror finishing. Whether or not the material can achieve a true “mirror” finish depends on the smoothness of the surface. Based on experience, we estimate the reflectivity should be about 90 to 100% (mirror) for a surface to be considered high gloss. You should be able to see reflections on the surface with clear lines, and even some indication of different background colors, tinted by the color of the paint which is blue in the example below. For a white paint, you may even see the color of the reflection clearly. Below photo is one metallic mirror finish at almost 95-99%.
2. Gloss, 60 – 85% sheen: This appears to be a range between the semi-gloss and high gloss, mostly used for generic purpose for surfaces that does not need to be “high” gloss, but yet it is not semi-gloss or 50% sheen. We would say it is a range somewhere between 65 – 85% sheen. As you can see in the illustration below, the trees and roads are still clearly discernable but the lines are blurred and not as sharp as high gloss.
3. Semi-Gloss, 40-60% sheen: This is a mid-range between two extremes of high gloss and matte finishing. You could barely recognize the items in the reflection as the outlines are completely blurred but you can roughly pinpoint the items in the reflection.
4. Satin, 20 – 40% sheen: This is an ambiguous zone like the generic “gloss” that is between medium and the matte. Some may even refer this or the “Low-Gloss” as the egg shell finishing. If you see the illustration below, it may remind you of the satin cloth. There is still a hint of very blurred reflection but that is the beauty of satin – there is reflection but just a shape that moves with the material. The lines are almost completely gone.
5. Low Gloss, 5 – 20% sheen: Some designers specify a low gloss surface, which is likely between matte and satin. It is hard to differentiate between low gloss and satin, but you can notice that the reflection is getting blurred and merges with the overall color.
6. Matte, 0 – 5% sheen: This is the easiest. You should not be able to see any reflection on the surface.
If you notice from the above illustrations, the same blue color gets darker as I reduced the sheen. This is due to reduction of reflected light.
So when you compare the color finishing of the actual item, be it a wall, furniture, against a color swatch (such as Pantone, BM or RAL), please note that they will not look 100% the same. For example, use coated Pantone for glossy paint, and uncoated for matte finishes. If then, it can still be challenging to compare the colors visually to see if they are matching.