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Color sheen chart


Types of Paint Finishes | Paint Sheen Guide

From Spotlight: Paint to Go from Blah to Ooh La La!

Choosing the wrong type of paint finish could mean a do-over that costs twice as much.

Image: boonchai wedmakawand/Getty

There’s a basic rule of thumb to follow when choosing paint sheens: The higher the sheen, the higher the shine -- and the higher the shine, the more durable it will be.

Flat paint has no shine; high-gloss is all shine. In between are eggshell, satin, and semi-gloss, each with its own practical and decorative job to do. 

Here’s how to choose the right paint sheen for your painting job.

Image: HouseLogic

High Gloss

The most durable and easiest to clean of all paint sheens, high-gloss paint is hard, ultra-shiny, and light-reflecting. Think appliance-paint tough.

High gloss is a good choice for area that sticky fingers touch -- cabinets, trim, and doors. High-gloss, however, is too much shine for interior walls. And like a Spandex dress, high gloss shows every bump and roll, so don’t skimp on prep work.

Semi-Gloss

Good for rooms where moisture, drips, and grease stains challenge walls. Also great for trim work that takes a lot of abuse.

Satin

Has a yummy luster that, despite the name, is often described as velvety. It’s easy to clean, making it excellent for high-traffic areas. Its biggest flaw is it reveals application flaws, such as roller or brush strokes. Touch-ups later can be tricky. 

Eggshell

Between satin and flat on the sheen (and durability) scale is eggshell, so named because it’s essentially a flat (no-shine) finish with little luster, like a chicken’s egg. Eggshell covers wall imperfections well and is a great finish for gathering spaces that don’t get a lot of bumps and scuffs.

Flat or Matte

A friend to walls that have something to hide, flat/matte soaks up, rather than reflects, light. It has the most pigment and will provide the most coverage, which translates to time and money savings. However, it’s tough to clean without taking paint off with the grime.

Tips For Choosing the Right Sheen

If your paint color is dark and rich but you don’t want a super shiny effect, step down at least one level on the sheen scale. That’s because the darker and richer the paint color is, the more colorant it has, which boosts sheen. Ditto if you’re painting a large, sun-washed, or imperfect wall. The higher the sheen, the more defects will show.

Adding sheen also adds to the cost, usually an extra dollar or two per gallon as you step up on the sheen scale.

Related:

More in Improve

Which paint sheen is the right paint sheen for your home painting project? -

At Mission Painting and Home Improvements, we not only strive for a hassle-free customer experience, but we also hope to provide our customers with some educational hints along the way.

After selecting a paint color, the next item to consider is what sheen is right for the project in your home.

Paint sheen refers to the luster, or brightness, of a specific paint finish.

Paint sheen is important to consider for both visual and functional reasons.

There are 5 paint sheens that you should be aware of: High Gloss, Semi-Gloss, Satin, Eggshell (or Matte in some products), and Flat.

A High Gloss finish provides a more durable finish that is great for higher traffic areas such as kitchen cabinets, front doors, trim and molding. A High Gloss finish works both on the interior and exterior of your home and is easily cleaned. One important thing to consider is that the higher the gloss the more imperfections will be visible.

A Semi-Gloss finish is a step down in luster but is incredibly useful in a different variety of spaces. Semi-Gloss finishes are perfect for spaces that take a lot of abuse, deal with moisture, or high traffic spaces. We recommend using a Semi-Gloss finish on bathrooms, kitchens, garage doors, and metal gutters. Similar to a high gloss finish you will find Semi-Gloss easy to clean while still showing imperfections in the paint and wall.

A Satin finish is highly versatile and has been described as velvety. It is highly durable and still very cleanable. Satin finish is perfect for active rooms like your family room, kid bedrooms, playrooms, window frames, and laundry rooms. You can also get these performance qualities by choosing a better-quality paint recommended to you by your Mission Painting team. Satin is Mission Painting’s preferred sheen for trim (baseboards, doors, cabinets, etc.).

Eggshell (or Matte in some products) is a sheen that has little shine but is much better at hiding imperfections. It is great for low-traffic areas in the interior of your home like your dining room, low traffic hallways, and adult bedrooms. Eggshell is not as easy to clean as glossier finishes. Eggshell or Matte is Mission Painting’s preferred sheen for walls. 

Flat is a completely no shine finish. It brings a soft look to walls and camouflages imperfections incredibly well. Flat finishes can be used in master bedrooms, offices, formal sitting rooms, or on ceilings. Cleaning a Flat finish is much more difficult. Any cleaners used may damage the paint. Flat is best used for ceilings.

There are many important decisions to be made in a painting project and selecting the right paint sheen should be near the top of your list. The experts at Mission Painting and Home Improvements are here to assist you in deciding not only the right color for you but also the right sheen for your painting project.

 

Grade of colored gemstones. Introduction to the "World of Color" by GemGuide - Workshop

08/24/2021 Gemology 3275

Alexey Lagutenkov

Website: Go to

Independent expert gemologist. Scientific titles: G.G. GIA (Chartered Gemologist, Gemological Institute of America), A.J.P. GIA (Gemological Institute of America Accredited Jewelery Professional), MBA Kingston University UK (Master of Business Administration from Kingston University UK). nine0006

Author of the bestselling book "Precious Stones".

Other expert publications:

There is nothing easier and more enjoyable than evaluating a certified colorless or nearly colorless diamond with a gemological report attached to it. The conformity of a stone with a document can be formally checked by simply looking at the girdle of the stone through a microscope. Does the number match the report? Corresponds! Then we get Rapaport's price list and make adjustments for cutting and fluorescence. No sorrows and doubts, in contrast to the assessment of a colored jewelry stone. nine0006

The problem of evaluation of colored gemstones is very old and very difficult. There are several reasons for this. "Closed market" and complex logistics, which involves many intermediaries - are not the most important. Most frustratingly, the industry lacks a well-established “standard of valuation” similar to diamonds.

Formalized assessment of the color of a stone, with reference to its current value on the market - several price aggregators are trying to solve this problem at once. Some of them use to a greater or lesser extent the GIA color notation for colored stones (Russian Ministry of Finance, Palmieri and GemVal), others use their own description of shades (Michelsen), and finally, others use the Munsell system. All of these systems use an incompatible color data format, as a result of which it is not possible to directly translate a hue description from one system to another. nine0006

Figure 1. GIA color system for grading colored gemstones.

Figure 2. Gemguide's World of Color color system based on the Munsell color space.

Gemological labs add to the complexity, as they do not use any of the above systems to describe color. The most authoritative gemological laboratories in the world issue reports on colored stones, as they say, “without details”. For example, Gubelin and GIA indicate the color of a sapphire simply: "Blue" (translated from English. "Blue"), ruby ​​"Red" (translated from English. "Red"), and emerald "Green" (trans. from English. "Blue"). "Green"). At the same time, no one specifies how exactly these shades are blue, red or green. This fact greatly complicates the assessment, since one of the most important characteristics of any gem, which determines its value, is its color. nine0006

One conclusion can be drawn from this: the laboratory report of the gemological laboratory on a colored stone, of course, is an important thing for understanding the nature of the origin of the gem and the degree of its refinement, but in order to get a specific figure, how much this stone costs in dollars or rubles, you will have to evaluate the color on your own or invite a specially trained specialist - a gemologist.

Of all the systems mentioned above, the most detailed and logical is the "World of Color" notation from GemGuide. This system allows you to determine the exact cost of more than 90 varieties of different jewelry stones. In addition, unlike other aggregators, World of Color is a turnkey, holistic gem valuation solution that does not require additional fuss. It is enough to buy their set of brochure and printed shade catalog, as well as subscribe to the magazine, in order to immediately receive all the necessary tools for evaluation. In this article I will try to explain the operation of this system as concisely as possible.

"World of Color" differs markedly from the GIA color notation. Compare Fig.1 and Fig.2. The GIA system has 31 colors, 7 tones and 6 saturations for warm and cold shades separately. In the "World of Color" GemGuide - 40 color shades, 9saturation (chrome) and 8 tones.

Photo 3. GemGuide, color catalog and main brochure of the World of Color system

The Gemguide themselves talk about World of Color like this:

World of Color is a stand-alone, portable color communication system . It is a loose-leaf album with 40 color pages, which represent the shades of colors in the Munsell system. Each page is complemented by a transparent overlay showing the corresponding color name for each Munsell notation. The set comes with a "Crown of Gems" designed to simulate color in a 3D gem using a flipbook. In the last section of our album, there are 50 tables for color evaluation and pricing of popular colored stones. GemGuide uses a quality rating scale from 1 (lowest quality) to 10 (highest quality) for all colored gemstones. nine0006

The World of Color book has been specially designed for use in evaluating colored stones. Although the basis of the system is the Munsell colors, in some areas a special color processing called the Pantone Matching System (trans. from the English “Pantone system”) is used, which allows you to connect complementary colors to those represented in the Munsell system. The result is a complete solution that includes a catalog of over 1500 colors, making the World of Color system useful for color grading of most gemstones. nine0006

Color observations should be made under standard lighting conditions using fluorescent lamps with a color temperature of 6500°K, which closely corresponds to the average daylight of the northern sky. For this system, it is recommended to use standard fluorescent lamps that emit light with a color temperature of 6200°K or higher.

The World of Color system uses a 1 to 10 gem quality rating system. Commercial grades 1 to 4 are designed to grade inexpensive gems commonly used in mass-produced jewelry. "Good" category from 5 to 6 quality groups (English Good) describes expensive stones of the premium segment. "Excellent" category 7 and 8 group is intended for evaluation of gems of the highest quality (eng. Fine). Finally 9and 10 groups (eng. Extra Fine) are extremely rare, exclusive stones of the highest quality. This price group of gems is so rare that it is unlikely that these stones will ever catch the eye of a “random” person.

For some gems, it is important to know the geography of their origin. This greatly affects the final cost of the stone. "Rubies" and "Burmese rubies", "emeralds" and "Zambian emeralds" or "Colombian emeralds" are valued according to completely different value tables.

The GemGuide themselves do not name their "assessments of the quality of stones" in any way. In Russian, this is long and inconvenient, so in this article I will call these grades “grades” so as not to completely get confused in all the numerous coefficients that will be discussed later.

Consider a small case in which a certain stone was brought to us for evaluation. At the exit, we must evaluate the gem using the World of Color system and name the price or range of prices, how much such a stone can cost in US dollars. We have at our disposal a qualified gemologist, a catalog of colors and the main brochure of the World of Color system, as well as one of the latest issues of the GemGuide magazine. nine0006

The most important step in assessing a stone is determining the color. The color determines the highest possible grade of the stone. Further, this grade is reduced, depending on certain imperfections of the gem. All characteristics of the stone in the World of Color system are assumed to be ideal and, if they are far from such, “discounts” are applied, which we will talk about.

Let's start in order. Suppose, with the help of a gemologist, we have determined that our appraised stone is an exotic natural apatite weighing 4.5 carats. How much can it cost? nine0006

As mentioned above, we first determine the color of the stone. To do this, open the catalog with color tables and begin to select a shade that matches our apatite. Let's say page 7.5BG fits perfectly, at the intersection of line number 5 and column number 8.

Photo 4. Color Chart 7.5BG World of Color

The color is called 7.5BG 5/8 "Strong Blueish" Green”, and its quality grade is 9 (see Table 1). This is very close to the maximum, which, as we remember, is 10 units. However, it's too early to rejoice! nine0006

7.5BG

9

nine0130

8

4

nine0135

7

nine0002

6

8

6

nine0130

6. 5

8.5

9.5

10

10

nine0126

5

7.5

9

10

10

10

4

nine0130

3

nine0135

2

nine0002

2

4

nine0130

6

8

10

12

14

16

18

Apatite purity is Type II in the GIA nomenclature. This means that very minor inclusions are acceptable for this stone. Our specimen has a subtle crack, and the gemologist rated the stone's clarity as "Lightly Included". According to the "World of Color" system, the discount for the LI attribute is 0.5 grade. So our apatite moves from 9th quality category in 8.5.

Purity grade

Translation from English

Downgrade

FI (Free of Inclusions)

Free from inclusions

0

LI (Lightly Included)

With small inclusions

-0.5

MI (Moderately Included)

Moderate inclusions

nine0002 -1

HI (Highly Included)

Large inclusions

-1.5

EI (Excessively Included)

With excessive inclusions

-2

The cut quality and color distribution are also not to our gemologist's liking. She says that she sees a small zoning in the form of a “window” and the shine of the stone is somehow “not so”, “muffled”, 70 percent of what it should be. Maybe this is due to the fact that the stone has a too “small” crown. Subtract half a grade for small zoning (see Table 3), half a grade for "so-so" shine (see Table 5) and half a grade for a shallow crown (see Table 6). There are no complaints about polishing and symmetry. nine0006

Table 3. Downgrade for color zoning. When the color is uneven throughout the stone, this is called zoning. Examine the stone from all sides in search of zoning.

nine0126

Zone group

Color zoning description

Downgrade

Z1

With complete absence or slight zoning score

0

Z2

If zonation is slightly visible

-0. 5

Z3

nine0135

If zoning is noticeable, score

-1

Table 4. Decrease in texture grade. Texture - areas of alternating normal and low transparency in a gemstone. It is understood that most of the stones evaluated are transparent.

nine0536

Description of texturing

nine0126

Texturing groups

Downgrade

1

The stone is transparent or has a slight texture

0

2

Moderate texturing

-0.5

3

Visible texturing

-1

4

Very strong texturing

-1. 5

Table 5. Gloss rating. If the stone has a moderate to noticeable texture, do not rate the brilliance as the deduction for the texture rating has already been made.

Gloss groups

Visual shine of stone

Downgrade

1

75 to 100%

0

2

60 to 70%

-0.5

3

40 to 55%

-1

4

5 to 35%

-1.5

Table 6. Visual assessment of the proportions of the stone. Evaluate each of the proportions by eye and, if necessary, make reductions in the grade. Please note that the maximum total deduction for symmetry cannot be more than 1.5 points.

nine0880

Unacceptable

Acceptable

Small

High

Crown height

0

-0.5

nine0135

-0.5

Acceptable

Small

High

Pavilion depth

0

-0.5

nine0135

-0.5

Acceptable

Unacceptable

Bulge

0

-0. 5

nine0002

Acceptable

Unacceptable

Girdle thickness

0

-0.5

Acceptable

Platform size

0

-0.5

Ex Excellent

VG Very good

nine0536

G Acceptable

F Bad

P Very bad

0

0

-0.5

-1

-1.5

nine0126

Ex Excellent

VG Very good

G Acceptable

F Bad

P Very bad

0

nine0135

0

0

-0. 5

-1

The final grade of our stone 7.0. See the section "Apatity" in the GemGuide. Stones weighing 3.00 - 4.99 carats grade 7 are valued at $115 per carat. It turns out that our stone costs $517.5. nine0006

Complaint to GemGuide about too high cost of gems - I was interested, and I decided to do my own little research. I want to bring the result of this work to your attention, and at the same time show a comparison with domestic Price Lists from the Ministry of Finance of the Russian Federation.

There are four Russian colored stone price lists for sapphires, rubies, emeralds and alexandrites that use the highly simplified GIA color notation. As I said above, it is almost impossible to establish a direct correspondence between the Munsell shades used in the World of Color and Russian verbal descriptions of color, partly based on the GIA color system. The problem lies in the difference in the definitions of the color spaces themselves. For example, if the GIA uses a "brownish" modifier for warm colors, and "grayish" for cool colors to describe the poor saturation of stones, then in the Munsell system, a brown tint is considered a variety of yellow and does not apply to modifiers. The description of the color tones of the Munsell space is directly opposite to the description of the GIA. This can be seen in tables 9and 10.

GIA Tone

2

3

4

5

6

nine0536

7

8

GIA verbal tone description

Very weak

weak

Medium weak

medium

Medium dark

dark

Very dark

Munsell value

9

7-8

6

5

4

nine0135

3

2

GIA "Saturation" Warm colors

1

2

nine0130

3

4

5

6

GIA "Saturation" Warm colors verbal description

Brownish

Slightly Brownish

nine0130

Very Slightly Brownish

Moderately Strong

Strong

Vivid

Chroma Munsell

In the Munsell system, shades of brown are treated as a separate color, darker than yellow, and do not serve to describe the low saturation of warm colors. nine0006

GIA "Saturation" cool colors

1

2

3

4

5

6

GIA "Saturation" of cool colors verbal description

Grayish

Slightly Grayish

Very Slightly Grayish

Moderately Strong

Strong

Vivid

nine0135

Chroma Munsell

2

4

6

8

10

12 and up

These two tables are given in the description of the "World of Color" and, although they do not allow you to directly compare the colors of Munsell and GIA, they can be used to establish an indirect correspondence between the intensity of the color of the stone. If we compare the stones specifically in terms of tone / saturation and tone / chrome, we can draw interesting conclusions. nine0006

The easiest way was with sapphires. You can compare the color description from the CTO “Blue or blue with a slight violet tint” with GIA “B” (English Blue) and “vB” (English violetish Blue), and the first quality group of “medium lightness and strong saturation” with GIA 5 /five. In literal translation, there is a slight discrepancy between quality categories. The highest color groups for sapphires using the GIA notation are B and vB 5/6 and 6/6, i.e. "medium lightness and bright saturation" and "medium-dark lightness and bright saturation". That is, our first group of sapphire colors corresponds to the second in the understanding of the GIA. Further conversion of lightness/saturation 5/5 to Munsell 5/10 (excluding color) gives us 6-8 GemGuide quality groups (2.5PB 5/10 - 6 group, 5PB 5/10 - 8 group). Comparing the rest of the tone / saturation, for sapphires, you can make the following correspondence table:

CTO 45866412-05-2008 RF

1

2

3

4

5

nine0126

GemGuide

Fine 6-8

Fine 5-7

Good 5-6, Commercial 4

Commercial 2-3

Commercial 1-2

As you can see, in this table there is no mention of the "highest" quality categories of GemGuide 9and 10, with saturation/chroma values ​​of "4/12" to "4/14".

Comparison of rubies and emeralds proved to be more difficult than sapphires. Here it turned out to be much more difficult to establish any correspondence between color and value groups. If for rubies the main difficulty was the discrepancy between “saturation” and “chroma” for warm colors, then for emeralds the main obstacle is a superficial description of colors, in accordance with the TU, developed already in 1988 and valid to this day. The comparison resulted in two tables below. nine0006

STO 45866412-06-2008 RF

1

2

3

4

5

nine0126

GemGuide

Good 6

Good 5

Commercial 4

Commercial 3

--

0011

TU 95 1647-88 RF

1

2

3

4

5

GemGuide

Good 6

nine0135

Good 5

Commercial 4

Commercial 3

Commercial 1-2

As you can see, when comparing rubies, I was not able to match the characteristics at all. Neither the color description nor the tone/chrome description have anything to do with domestic counterparts. Nevertheless, let me suggest that rubies of our 5th color should be evaluated according to the Gemguides 1-2 commercial categories. With emeralds, too, not everything is unambiguous, and in many respects this comparative table is based on assumptions and assumptions. nine0006

Let's try to make a small comparison of prices to make sure that the resulting tables work.

Take the following stones:

Price according to RF Price List

Gemguide price

Note

Ruby 2/1, weight 1.5 ct, heat treated

$1725

$892 - $1170

Sapphire 1/3, 0.26 ct, heat treated

$44. 2

nine0002 $41.6 – $62.4

"3" purity quality group - we lower the purity rating by 1 grade to Moderately Included

Emerald 1/G1, weight 0.75 ct

$573.75

$262.5 – $412.5

It can be seen that Russian price lists, based on a rather vague definition of color, give completely unambiguous conclusions about the cost of a stone. Gemguide's approach is exactly the opposite: an accurate description of the shade of the gem according to the accompanying color standards and a price range that allows the appraiser to take into account the nuances of the quality of the stone. nine0006

Of course, the issue of valuation of gems is very complex and it is hardly possible to offer a quick and unambiguous solution to it. The advantage of Gemguide's World of Color gem valuation system is that it is the most comprehensive and consistent nomenclature available today, allowing you to judge the value of more than 90 types of gems, as well as diamonds, opals and pearls of all kinds. The absolute advantage of the system is ease of use. The GemGuide price catalog comes out once every two months, which is very timely for the amount of information they provide. Unlike other gem valuation tools, there are no software licenses to purchase, and no compatibility issues or upgrades. nine0006

Gallery

Coating gloss measurement (theory and practice). Glitter TQC.

Reliability of accuracy of brightness measurements.

The aesthetic properties of products are becoming increasingly important in modern production. In the 20th century, gloss measurement became one of the standard control parameters for evaluating the appearance of coatings. The specifications currently in use were developed based on the criteria for gloss sharpness and the numerical value of gloss obtained by a gloss meter. nine0006

Coating manufacturers, instrumentation manufacturers and standards makers are striving to achieve or maximize gloss requirements.

But how feasible are all these aspirations?

Gloss measurement became popular in the 1970s, when German test equipment manufacturers mastered the mass production of inexpensive gloss meters, the development of relevant standards and introduction into production lines began. The first gloss meters copied the principle of operation of the laboratory equipment used at that time for the paper industry. As technology improved and stricter requirements for appearance and gloss emerged, the tolerance value rapidly decreased. But while some gloss meter manufacturers were trying to achieve a convergence of 0.1 GU (Gloss Units), in practice, an accuracy of only 1 GU was often sufficient for end users. nine0006

Is this really accurate enough?

To answer this question, let's consider what the requirements of international gloss measurement standards are based on and how these measurements are made.

To numerically estimate the magnitude of the brightness, an appropriate scale and reference points are needed. Current standards define breakpoints of 0 GU and 100 GU. In this case, a value of 0 GU corresponds to a matte surface with zero reflection, and a value of 100 GU corresponds to a black glossy surface. Based on the intensity of light of a certain wavelength, reflected from the measured surface and depending on the angle of incidence and reflection, the reflection index is calculated. Calculations are made according to the Fresnel formulas for reflection and refraction of light. At first glance, this approach seems to be quite thorough, but due to the mismatch between ASTM and ISO specifications, it leads to different results. The fact is that according to the ASTM standard, the spectral line of helium (d) is used to measure the reference point of 100 GU, and according to the ISO standard, the spectral line of sodium (d1). The difference between these wavelengths is only 1.7 nm, but when it comes to international standards, even such a slight difference can lead to undesirable results. nine0006

First, it should be noted that the use of only two reference points is fundamentally insufficient to create a Standard. Moreover, the scale between these points is considered linear only conditionally. While there are, of course, tools to enforce and control this linearity, current standards do not provide for their use.

Secondly, non-specific factors also affect the measurement accuracy. So, for example, the surface roughness of the calibration plate is not taken into account either by the Fresnel formula or in the relevant standards. A number of standards regulate even the plane of the plate surface, but the roughness is defined only descriptively as “polished” (how polished?). However, the roughness of the plate has a direct effect on the reflection of the surface. Calibration plates from different manufacturers are made from the same material, but they have different roughness and surface textures. And despite the fact that the Fresnel formulas and the current standards assume that they have the same magnitude of brilliance, when measured in certifying laboratories, it is not possible to find two identical ones. nine0006

Thus, the question arises: “Does the surface roughness affect the gloss?”. And the answer is unambiguous: "Yes, it does, and this influence is significant."

Table 1.

Standard Wavelength, nm Multiplier Spectral line Finishing GU
ISO 2813 587. 6 nm 1.567 d (helium) Less than 2 interference rings per see 100
ASTM D523 589.3 nm 1.567 D1 (sodium) Polishing 100
ISO 7668 Not specified 1.567 Not specified Less than 2 interference rings per see 100
JIS Z8741 Visible spectrum 1.567 helium Not specified 100
ASTM C584 Not specified 1.540 Not specified Polishing 94
ASTM D1455 Not specified 1.567 Not specified Polishing 100
ASTM D2457 Not specified Fresnel Not specified Polishing 100

Table 1 shows the main parameters used in several leading standards. Minor inconsistencies between these parameters are responsible for the difference in brightness by several GU units. nine0006

As shown in Graph 1, the higher the surface roughness, the lower its gloss.

Graph 1 shows gloss versus roughness. The change in the light curve is correlated with the Ra value curve (roughness). All data were obtained on black calibration plates made from the same material and marked with the same reflectance index.

Both reasons, the surface roughness and the wavelength of the spectrum line used, for a long time are constant obstacles that violate the unity of international specifications, which makes it impossible to use several standards simultaneously, although the design and geometry of gloss meters in all modern standards are the same and allow this. This is the price of the significant discrepancy in the graphs shown in Table 1. This discrepancy is observed even in the data of the world's leading certifying laboratories NIST and BAM, since NIST relies on the ASTM standard, and BAM on ISO. nine0006

The problem is compounded by the fact that in this case it is difficult to get a direct benefit from achieving harmony between standards. Ideally, the benefit would be a positive result of the experiment, science in its purest form. The technical literature does not present any significant studies on the effect of surface roughness on gloss and reflection. Although, of course, there are several important and similar measurement parameters, but what serves as a standard for them? Haze, distortion (DOI) and orange peel are both relative and have no international standards. Theoretically, they could be used in the gloss standard, but at the moment they raise more questions than answers. nine0006

A number of scientific studies have been carried out using the Beckmann-Kirchhoff theory of light scattering on a rough surface, but the lack of a mathematical model does not allow linking this theory with the Fresnel formula. It is expected that further research will lead to a single system that will combine existing standards and create a definitive and unambiguous definition of the gloss calibration plate that meets both the ISO standard and the ASTM standard. nine0006

However, in addition to the uncertainty in the use of standards, there is another important cause for concern. We are talking about the possibility of periodically monitoring the accuracy of measurements. It is very important for all certified laboratories to regularly check their calibration plates. In this case, it is desirable that the accuracy of the value of the calibration plates is an order of magnitude higher than the accuracy of the one being checked. This, in turn, also implies an annual check of the condition of the calibration plates themselves. nine0006

Many ISO 17025 certified calibration laboratories calibrate custom plates supplied with conventional gloss meters by measuring them with the same conventional gloss meters. These gloss meters are calibrated against certified BAM plates, which have an accuracy of ±1 GU in the 100 GU range. This spread of accuracy adds up to the convergence and reproducibility of conventional gloss meters used for the verification process, resulting in a total error of just a few gloss units (GU). nine0006

Now is the time to return to the question of the credible accuracy of existing standards!

Primary verification standards from BAM and NIST must be verified according to their reflectance indices. But over the past 15 years, there has never been a cross-check of standards between these leading institutions. Many aspects related to the measurement of gloss, such as the relationship between roughness and gloss, the wavelength of the spectral line, the apparent linearity of the gloss scale, have not yet been clarified and need to be worked out. nine0006

The current situation has become one of the reasons for changing the ISO standard for gloss - ISO 2813. In order to improve the quality of work, the ISO charter provides for an algorithm for the cyclic distribution of tasks between departments or “inter-laboratory exchange of experience”. In this case, conventional gloss meters from leading manufacturers are used. In the course of these works, it was found that the convergence and reproducibility indicated in the documentation of the devices is far from reality. Moreover, this discrepancy increases over time. Based on these studies, it was decided to revise the requirements of the ISO standard for convergence and reproducibility, which was reflected in the new edition of ISO 2813. They show the real level of modern professional gloss meters of the highest accuracy class (table 2). nine0006

Table 2

Angle Convergence Reproducibility
20° 3GU 4GU
60° 2GU 3GU
85° 1GU 2GU

Table 2. Recommended in the new edition of ISO 2813, the accuracy and reproducibility of measurement data of gloss meters

Terminals

The ISO commission took the first step by updating the ISO 2813 standard. However, this solved only part of the issues. The core of the problem lies in the primary standard itself. All measurement data is based on a single reference point obtained on a glass plate, with an unconfirmed linearity of the scale. Ideally, it is desirable to develop several materials that have the required reliability and choose additional intermediate points on the scale. On the basis of these materials, it is also desirable to confirm or refute the assumption that the light scale is linear. There is an urgent need for an exhaustive scientific study of the influence of roughness and wavelength on gloss, in order to develop a detailed, unquestionable description of the primary gloss standards for ISO and ASTM. These primary standards should have an accuracy an order of magnitude higher than the accuracy of the verified gloss meters. nine0006

Such scientific research would have a huge impact on the industry. All gloss specifications would be changed to be more realistic and correct. Despite the fact that for most industries, the criterion for the quality of the appearance of a product is the amount of gloss, the realization of the fundamental imperfection of the existing concept requires a radical revision of the evaluation criteria and the accuracy of the data obtained.

Choice of gloss meter

At the moment, a large number of gloss meters of domestic and foreign production are presented on the Russian market. If you look at them from a technical point of view, you can say: "They are all the same and use the same principle of operation." But if you look at them from the side of functionality, it can be noted that each manufacturer is trying to add some kind of “zest” to their devices. Often this leads to a significant increase in the cost of devices. Also, some manufacturers, in pursuit of "beautiful numbers", try to indicate such accuracy that can only be obtained in ideal and theoretical situations that cannot be reproduced in real conditions. The reader who has read this article, when choosing a gloss meter, will be able to independently analyze the characteristics of the considered gloss meters, accept or doubt the parameters declared by the manufacturer. nine0006

As a recommendation, I would like to mention gloss meters from TQC, the Netherlands. TQC has been manufacturing laboratory testing equipment for over 30 years and is actively involved in the development and revision of international standards. TQC employees are members of the current ISO committees, so we can safely say that it is TQC devices that meet modern standards. The rich functionality of gloss meters and European quality distinguish TQC gloss meters from many other devices. And due to the fact that TQC itself produces these gloss meters and all their accessories, the price of these gloss meters compares favorably with the prices of other European, American and Japanese manufacturers. nine0006

There are 3 modifications of gloss meters on the Russian market:

  • Single Angle TQC SoloGloss (60°)
  • Dual angle DuoGloss (20°,60°)
  • Three-angle PolyGloss (20°, 60°, 85°)

Specifications of TQC Gloss Meters:

nine1756 85
20 60
Measuring range 0 – 2000 GU
Convergence 0.

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