Gray Scale Hiding Power Paint Chart
Article No. 12737
Leneta 24B Opacimeter Chart 250/Bx
The Gray Scale Hiding Power Paint Chart is a sealed paint test chart with six stripes on a white field, ranging in shade from light to dark gray and black. The stripes are numbered from 1 to 6 with increasing darkness and provide contrast steps suitable for demonstrating the hiding power of typical trade sales coatings.
Features
The reflectance values of the numbered stripes are selected with the objective that their color differences with respect to the white surround will be in the geometric sequence: 2, 4, 8, 16, 32 and 64 CIELAB units. The defining variable for the gray stripes is not reflectances as such, but the ratio of the gray to white reflectance, G/W. The table gives their specifications and tolerances, which are the same as stated in ASTM Method D5150 for Form CU-1.
- Size: 7-5/8 x 11-3/8 inches (194 x 289 mm)
- Thickness: 12 mils
Technical Attributes
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- Data
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Stripe No. Color Difference2 Ratio G/W3 Reflectance G%4 1. As stated in ASTM Method D5150 for Form CU-1.
2. This is ΔE*ab, the color difference with respect to the white background, expressed in CIELAB units as defined in ASTM Method D2244.
3. G/W = (1 - ΔE*ab/107.7)3. This equation is derived from ASTM Method D2244 and assumes that for neutral gray versus white, the values ΔE*ab and ΔL* are sufficiently close to be considered equal for the purpose of this test method.
4. These values vary somewhat with the reflectance W of the white area, which is normally 80 ± 2% inter-batch and ± 0.5% intra batch. Values shown here are calculated for W = 80%.1 2 ± 12.5% 0.945 ± 0.007 75.6 ± 0.6 2 4 ± 12.5 0.893 ± 0.013 71.4 ± 1.0 3 8 ± 12.5 0.793 ± 0.024 63.5 ± 1.9 4 16 ± 12.5 0.617 ± 0.042 49.4 ± 3.4 5 32 ± 12.5 0.347 ± 0.055 27.8 ± 4.4 6 64 ± 12.5 0.067 ± 0.037 5.3 ± 3.0
Standards
Conforming with ASTM Method D 5150
Procedure
- Apply the paint with a 6 mil clearance (nominal 3 mil wet) film applicator and allow the film to dry.
- Report the hiding power as the number of the stripe that is almost but not completely obscured.
- For a more accurate hiding end point use a visual comparison standard (Contrast Ratio: 0.98).
- If the hiding end point falls between two consecutive stripes, add a fractional estimate.
- If a hiding power end point is not observable because the film hides too well or too poorly, reapply the paint with an applicator of higher or lower clearance as required to obtain an end point.
- The complete hiding power report should state the applicator clearance along with the shade number of the hiding end point.
Delivery Content
Includes 250 per box