ASTM C609-07(2014)
Standard Test Method for Measurement of Light Reflectance Value and Small Color Differences Between Pieces of Ceramic Tile

Standard No.
ASTM C609-07(2014)
Release Date
2007
Published By
American Society for Testing and Materials (ASTM)
Status
Replace By
ASTM C609-07(2019)
Latest
ASTM C609-23
Scope

5.1 This test method describes the means of determining the LRV of a tile specimen. Certain building codes require the use of materials rated by LRV. Application of this test method provides the means for rating ceramic tile. LRVs reported for ceramic tile should include reference to the observer and illuminant for which the rating is valid.

5.2 LRV is a property dependent on the overall color of a tile specimen. Control of LRV is achieved through control of color and adherence to color specifications will govern the acceptability of a product with respect to LRV. Therefore, a product cannot be judged as having an unacceptable LRV unless the color of the product is found to be unacceptable.

5.3 Mixtures of several tile products are commonly installed on a surface, requiring a means to calculate LRV for a product mix. The rating obtained for an individual tile product can be used to calculate the LRV for a product mix using the following equation:

Equation C0609-07R14_2
where:

n   =   number of products included in the mix
p1 to n   =   the proportion of the surface area taken up by each product, the sum of p1 to pn must equal one
LRV1 to n   =   the LRV for each product used
For example, a mixture of two products is used on a surface. Two thirds of the surface area is covered by product A with a LRV of 758201;%, and one third of the surface is covered by product B with an LRV of 608201;% (see Fig. 2). Using the equation, the product mix is found to have an LRV of 708201;%.
Example of a Product Mix Used on a Surface

FIG. 2 Example of a Product Mix Used on a Surface

5.4 The test method described herein provides instrumental means as the basis for judging color difference. Magnitude of color difference between pairs of ceramic tile can be determined and expressed in numerical terms.

5.5 Based on interlaboratory investigation,3 color difference ΔE of plain-colored tile, if determined according to this test method, should give excellent reproducibility with a standard deviation of not more than σ8201;=8201;±0.15 units. LRV should also give excellent reproducibility when used for solid colored tile based on the relationship between LRV and either the Y tristimulus or L value. However, LRV reproducibility for multicolored, speckled, or textured surface tile will be dependent upon the degree of variation of the tile specimen, and will require a different measurement procedure to minimize the impact of the variation.

5.6 The test method requires the use of multiple illuminants for the determinati......