Specifiers: Labels that sell sheen - what do they really mean?









Neither the hen nor the rooster can recognize 'eggshell' !!!

A specifier chooses a "finish" partly for appearance and partly for performance. This "finish" is technically known as the gloss reflectance or specular gloss level.

The gloss reflectance we know as "flat" is not overly complicated, nor is the gloss reflectance at the opposite end of the scale - "gloss" or "high gloss". The "semi-gloss" finish is also not in great dispute.

It is that which lies between the "semi-gloss" and the "flat" which causes not only specifiers, but also many within the industry, to tear their hair out. The term "eggshell" is widely used to describe that 'no man's land' between semi-gloss and flat.

Originally, the term was intended to convey a description of the range of somewhat low gloss reflectance (also called "sheen") which most closely resembled the sheen on the protective shell of an egg. Confusion developed, however, as to whether or not "eggshell" also meant color. As we know, the color of the shell of an egg can vary from white all the way to brown. That same wide variance also appears not only with the gloss or sheen of "eggshell", but also with the terminology!

The following terms are used by some manufacturers to describe the range from "flat" to "semi-gloss": silk, suede, satin, pearl, melamine, velvet, platinum, lo(w) luster (or lustre), lo(w) sheen, eggshell, low sheen eggshell, etc. etc. Who, besides the manufacturer, knows what each means? And when?

Even if all could agree on one name, would that solve the confusion? No! The gloss reflectance levels vary from a legitimate flat to a legitimate semi-gloss, not just from one manufacturer to another, but often within the product range of a single manufacturer. Even when the finishes are standardized within the water borne lines, the solvent borne lines differ yet again! Therefore, it is a real challenge to get the same sheen on a wall with a latex system as on the adjoining doors and frames with an alkyd system. Even if that were achieved, tinting the product (particularly in deep and accent colors) may change one or the other. For example, many times, tinting to deep and accent colors can increase sheen in latexes while decreasing sheen in alkyds.

Further complicating this common confusion, is the paint applicator who chooses the lowest sheen "eggshell" available to hide drywall finishing (or other) defects, while still meeting the spec. The use of this lowest sheen "eggshell" may not now meet the specifiers requirements for washability and abrasion and/or mar resistance. And, it certainly won't meet the specifiers requirements if the color consultant chose deep or accent colors requiring the addition of substantial amounts of "tinters" or colorants.

Two e-mails to our website this past month demonstrate the frustration felt by many in the industry. The first is from a professional specification writer with a significant architectural firm in a major market. "We are having difficulties in defining gloss and sheen terms in our specifications. It appears that not all manufacturers use the same definitions when it comes to gloss and sheen terms, and there is no consensus among the ASTM and CGSB standards. Can you help in providing a set of definitions based on 60 degree and 85 degree head metering?"

The second is from a professional specification writer with a supply and services department of a major government. He notes that he is responsible for maintaining master painting specifications and has a direct interest in the "quality of paint, its technical aspects and application on construction projects". Among other performance requirements, "I would like to see the industry adopt a standard gloss range classification."

Here are two specification professionals, both with a substantially better-than-average understanding of this aspect of coatings and their application. Both share the frustration caused by the lack of industry standards.

The manufacturing and marketing of premium paints is a very complicated process, and the industry is unlikely to soon change either its established manufacturing formulas or its marketing. Until then, confusion is sure to continue.

In the meantime, The Master Painters Institute has established standards for gloss reflectance. While not yet perfect, these standards begin to provide further information to the specifier and applicator as to 'apples-to-near apples' comparisons. ["Gloss/Sheen Description" from Products - Chapter 5, Section 1, Appendix B of one of the MPI Technical Manuals]

The March 2004 MPI Approved Products List will take another step toward standard classification with new performance requirements for categories and with new published exceptions to MPI gloss reflectance (i.e. finish) standards.

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