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Characteristics of Leneta Paint Charts and Cards

1. Characteristics of Charts and Cards

Technical Data
Lacquer Sealer:
Applied one side only; solvent resistant; non-migrating.
Black Areas: Printed one side only; non-bleeding, reflectance 1% max.1
White Areas: Color retentive; non-fluorescent; reflectance 80% min.1
Thickness2: Charts—11 mils (0.28 mm) / Cards—20 mils (0.5 mm)
Weightage2: Poundage lb/Mft2 56 charts 273 charts
Grammage g/m2 74 cards 361 cards
Hole Punching3: One hole—1/4" (6mm) diameter
Two holes—3/8" (9.5mm) diameter, 4-1/4" (108mm) between centers.
1 Measured per ASTM E1347
2 Approximate
3 Indicated by illustrations or in the test.




2. CIE-Y Reflectances of Grays

Technical Data
Form G %
5DX-GW 46±3
8H-GW 46±3
8K-GW 46±3
10H-BG 34±3
24B Gray Scale
CU-1 Gray Scale
M* 31±3
S* 31±3
*Represents additional letters and/or numbers to identify two or more related products.
Gray Scale Specifications1
Stripe Number Color Difference2 Ratio G/W3 Reflectance G%4
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
1 As stated for Form CU-1 in ASTM Method D 5150.
2 This is ΔE*ab, the color difference with respect to the white background, expressed in CIELAB units as defined in ASTM Method D 2244.
3 G/W = (1- ΔE*ab/107.7)3 This equation is derived from ASTM Method D 2244 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. Values shown here are calculated for W = 80%




3. U.S. - Metric Conversions

Technical Data
Length: 1 in = 2.54 cm = 25.4 mm
1 mil = 25.4 μm
1 mm = 39.37 mils
1 ft = 30.48 cm = 0.3048m
Area: 1 in2 = 6.4516 cm2
1 ft2 = 929.0304 cm2
1 m2 = 10.76391 ft2
Volume: cc ≈ cm3 ≈ mL; L ≈ dm3
1 in3 = 16.387064 mL
1 ft3 = 28.3168 L = 7.48052 gal
1 gal = 231 in3 = 128 fl.oz = 3785.412 mL
1 fl. oz = 29.5735 mL
Weight: 1 lb = 453.59237 g
1 av.oz = 28.3495 g
Density: 8.3454 lb/gal = 1g/mL = 1kg/L
Spreading Rate: 40.746 ft2/gal = 1 m2/L
4.8824 ft2/lb = 1 m2/kg
Weightage (Weight/Area): Poundage (lb/Mft2) x 4.8824 = Grammage (g/m2)
Temperature: °F = 1.8 x °C + 32
°C = 5/9 (°F -32)
Notes: (1) Relationships in bold type are exact. (2) 1 gal (Imperial) = 1.20095 gal (U.S.)




4. Spreading Rate vs Film Thickness

Technical Data

H = spreading rate (whole paint)

T = wet film thickness

t = dry film thickness *

D = whole paint density

d = dry film density *

N = nonvolatile fraction by weight

Nv = nonvolatile fraction by volume

* displacement basis

4.1 Metric Units

a) H(m2/L) x T(μm) = 1000

b) H(m2/L) x t(μm) = 1000 ND/d

c) H(m2/kg) x T(μm) = 1000/D(kg/L)

d) H(m2/kg) x t(μm) = 1000N/d(kg/L)

4.2 U.S. Units

a) H(ft2/gal) x T(mil) = 1604.2

b) H(ft2/gal) x t(mil) = 1604.2ND/d

c) H(ft2/lb) x T(mil) = 1604.2/D(lb/gal)

d) H(ft2/lb) x t(mil) = 1604.2N/d(lb/gal)

4.3 Dry vs Wet Films

a) ND = Nvd

b) t = NvT

c) td = NTD




5. Equations for Spreading Rate Charts

(Laboratory operations in grams and mL)

Technical Data

T = wet film thickness

V = volume applied

H = spreading rate

M = weight applied

D = Paint density

5.1 All Metric Units

a) V(mL) = T(μm) + 10

b) V(mL) x H(m2/L) = 100

c) T(μm) x H(m2/L) = 1000

d) M(g) = V(mL) x D(g/mL)

e) M(g) = T(μm) x D(g/mL) ÷ 10

f) M(g) = 100 D(g/mL) ÷ H(m2/L)

5.2 All U.S. Units

T(mils) x H(ft2/gal) = 1604.2

5.3 U.S./Metric Units

a) V(mL) = T(mils) x 2.54

b) V(mL) x H(ft2/gal) = 4074.6

Note: Equations above in standard type apply only to 0.1m2 (1000cm2) area charts. Those in bold type apply to test areas of any size.




6. General Hiding Power Methodology

Technical Data
6.1 Definitions

Hiding Power is defined as the Spreading Rate required for full hiding over a standard black and white substrate, which is specified in coatings technology to have CIE Y- reflectances of 0.01 (1%) max. and 0.80 (80%) respectively.* Sometimes substrates with other shades or color combinations are employed. Full hiding for visual observations means just short of total extinction of contrast. Photometrically it is defined as 0.98 Contrast Ratio, at which there is likewise a slight amount of visual contrast.

*Specular reflection excluded.

6.2 Film Application

The objective is to determine the spreading rate at a specified level of dry film opacity, which is usually full hiding as perceived visually or corresponding to the contrast ratio: C = Ro/R0.80 = 0.98. The basic experimental procedure is to apply a uniform film on a suitable test substrate, to observe its opacity either visually or photometrically, and to determine its spreading rate. Since it is not possible to apply a film with precision at a predetermined dry opacity, several such applications need to be made over a range of spreading rates and their results plotted graphically or otherwise interpolated to the desired spreading rate end point. A converse procedure is to apply coatings at a prescribed spreading rate or film thickness, and after drying to measure their contrast ratios or to compare their hiding visually.

The results are only comparative since true hiding power, as defined in 6.1, is a spreading rate. 6.3 Spreading rate (or film thickness) determination - In both visual and photometric hiding power methods, the procedures for observing film opacity are well defined and can be performed with dispatch. The experimental task that is most demanding on the operator’s time and ingenuity is to determine the spreading rate or film thickness of the applied coating with good precision. Although gages are available for measuring wet and dry film thickness directly, it is more accurate to determine the weight of dry paint film on a measured test area and then to calculate the spreading rate or film thickness from relevant portions of the following equations:

Spreading Rate Equations

Metric values thus calculated can be converted to U.S. common units via the following relationships:
H(ft2/gal) = 40.746 H(m2/L) (3)
H(ft2/lb) = 4.8882 H(m2/kg) (4)
T(μm) = 25.4 T(mils) (5)
D(lb/gal) = 8.3454 D(kg/L) (6)
Powder coatings are usually considered as being volatile-free, and their dry film and powder displacement densities (d and D) as equal. In that case Eq. 2 becomes: This less rigorous equation avoids the need to measure d or N.




7. Kubelka-Munk Hiding Power Calc

Ask For Details On (K-M) Hiding Power Calculator

Hiding Power Formula




8. Leneta Anti-Sag Meter

ASTM Method D 4400

Technical Data
A. Equipment
  1. The Anti-Sag Meter
  2. Adjustable Straight Edge
  3. Drawdown Plate - Regular
  4. Drawdown Charts* Form 7B black & white, for light colored paints. Form WB plain white, for dark colored paints.
  5. Catch-Papers, Form CP-1
  6. Pre-shear equipment
*With the Low Range Anti-Sag meter use glass or flat metal panels.
B. Preparation of Coating
  1. Stir well and adjust to 23°C (73.5°F)
  2. Pre-shear in accordance with one of the pre-shear methods (Pre-Shear by Rapid Mixing - Solvent Coatings; or Pre-Shear with Syringe and Needle - Aqueous Coatings), and test immediately thereafter.
C. Application of Coating
  1. Attach the straightedge to the drawdown plate in suitable position.
  2. Place a test chart on the drawdown plate under the clip.
  3. Place the Anti-Sag Meter on the chart, adjacent to the clip, with its open side toward operator and its shoulder against the straight edge.
  4. Position the Catch-Paper.
  5. Place a suitable quantity (8-10mL) of pre-sheared paint directly in front of the blade, and draw down uniformly at about 6 inches (150mm) per second.
  6. Promptly fasten the drawdown to a vertical surface, with stripes horizontal like rungs in a standing ladder, left edge (thinnest stripe) at the top, and allow to dry in that position.
D. Rating the Drawdown
  1. Note the notch numbers marked on the Anti-Sag Meter and identify the corresponding stripes accordingly.
  2. Ignore the leading and trailing edges, and observe only the central 5-1/2 inches (140mm) of blade path, corresponding to the black area of Form 7B.
  3. The lowest (thickest) stripe that does not touch the one below itself is referred to as the index stripe, and its notch number is the Anti-Sag Index of the paint.
  4. For a more precise Anti-Sag Index add to the index stripe number the product of the post-index clearance step and the fractional degree to which it has failed to merge with the next lower stripe. The fraction is estimated in accordance with the following table:
Degree of Merger
Fraction Unmerged
Somewhat more than half
Approximately half
Somewhat less than half
E. Practical Interpretation of Ratings

This is empirical and strongly subjective. It should be emphasized that the Anti-Sag Index is not a wet film thickness; it is the clearance of the index groove expressed in Mils, and as such approximately twice the wet film thickness of the index stripe with emphasis on approximate. Neither the Anti-Sag Index nor the estimated corresponding wet film thickness is to be construed as calling for a specific thickness in practice. It is solely a numerical comparator and acquires practical significance only on the basis of experience. When a coating is perceived to have optimum sag resistance by actual application testing, the Anti-Sag Index is then measured and thereafter becomes the sag control value for that particular formulation.

The correct Anti-Sag Index for one product might be quite different than for another. Latex paints, for example, would normally have much higher index values than solvent-borne coatings. The following qualitative judgments were based on observations of a series of trade sales type alkyd gloss enamels, and are given here as examples only. They are not to be considered as definitive.

Anti-Sag Index Sag Resistance
Very poor
Very good

The above indices cover the range of the Standard Anti-Sag Meter, but many coatings require lower or higher index measurements. These requirements are met with Low, Medium, and High Range instruments, making it possible to measure Anti-Sag Index values from 1 to 60.




9. Leveling Test Procedure

ASTM Method D 4062

Technical Data
A. Equipment
  1. The Leneta Leveling Test Blade
  2. Drawdown Levelness Standards
  3. Leveling Test Drawdown Plate
  4. Drawdown Charts
    Form WB, for light colored paints
    Form 7B for dark colored paints
  5. Catch-Papers
  6. Pre-shear equipment
  7. The Level Luminator
B. Preparation of Coating
  1. Stir thoroughly and adjust to 23°C (73°F)
  2. Strain, and adjust viscosity if and as necessary.
  3. Pre-shear in accordance with one of the pre-shear methods and test immediately thereafter.
C. Application of Coating
  1. Position a Catch-Paper on the drawdown plate.
  2. Place a chart on the drawdown plate against the left guide.
  3. Place the test blade at the top of the chart with its long arm against the left guide and toward the operator.
  4. Place 8-10 mL of pre-sheared coating in front of the blade and draw down rapidly at a uniform rate of approximately 60 cm (2 ft) per second.
  5. Allow to dry in a horizontal position at 23°C (73.5°F).
D. Rating the Drawdown
  1. After drying cut out a 3 x 5 inch (75 x 125 mm) section, with striations parallel to the long edge.
  2. Compare with Levelness Standards under suitable lighting (Level-Luminator oblique for white or light colors, ambient specular reflection for dark colors).
  3. The number on the matching standard is the Leneta Drawdown Leveling Value. Rate perfect leveling as 10 and less than 1 as 0.
E. Practical Significance of Numerical Values
This is based on subjective evaluations. The following table represents the collective judgment of an experienced laboratory group:
Drawdown Leveling Brushout Value
Very poor
Very poor
F. Topography of Leneta Drawdown Levelness Standards
The following wave amplitudes were measured with a Talysurf 4 profilometer. The data is of interest because it links an objective physical parameter to subjective visual impressions.
Standard Number Amplitude
Mils μm


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