The term "Opacity Chart", as used in this catalog, refers to charts on which the test pattern is a simple combination of black and white areas, large enough for wide aperture reflectance instruments, as well as for visual opacity and color observations. Leneta opacity charts comply with all test methods specifying charts of such design. Such charts are sometimes refered to as "drawdown" or "hiding power" charts.
An important characteristic of architectural finishes is the ability to maintain a uniform appearance on surfaces of varying porosity. This ability, of which gloss and color uniformity are specific aspects, is referred to as penetration resistance. The adjacent sealed/unsealed areas of Leneta Form HB present severe conditions of varying porosity for testing penetration resistance. In addition to qualitative visual observations, photometric measurements on the two areas provide objective numerical values.
These combine the test areas and functions of a penetration and an opacity chart. They can be considered as universal test charts for research, development and quality control. The choices offered in size and design are responsive to individual laboratory needs and preferences.
These charts employ time-tested diagonally striped patterns, having a strong visual impact that emphasizes variations in film opacity. They are therefore frequently used for hiding power display purposes, by means of drawdowns or brushouts. Gray stripes in Form 8H-GW provide reduced substrate contrast for use with low hiding power coatings. Spreading Rate Charts (Forms 8H and 8H-GW) are accurately 0.1 square meters (approximately one square foot) in area, and are used in brushout hiding tests at specified spreading rates as described in ASTM Method D 344.
Charts of this type combine the large, unbroken areas that are characteristic of Opacity Charts, with the striped design of a Display Chart. The larger areas permit wide aperture photometric measurements and visual color comparisons, while the striped area is uniquely effective for hiding power comparison and display. Spreading Rate Charts (Forms 12H and 13H) are accurately 0.1 square meters (approximately one square foot) in area, and are designed for brushout application at specified spreading rates.
One of the earliest hiding power test surfaces was linoleum with a black and white checkerboard pattern. This was soon replaced by sealed paperboard charts of which Forms 10H and 10H-BG Spreading Rate Charts are typical examples. Designed for brushout tests at specified spreading rates, such as in ASTM Method D 344 and Canadian 1-GP-71, they are also used for drawdown applications like their smaller counterparts, Forms 10A and 10B. Black and gray squares in Form 10H-BG provide reduced contrast for testing coatings with lower hiding power.
These plain white Leneta Cards & Charts are sealed on one side so they are compatible with waterborne and most solvent based coatings. Plain white cards and charts are frequently used to produce true color samples, without the influence of a black substrate.
Plain white cards and charts are available in a variety of standard sizes. Special sizes are available upon request.
This unique drawdown blade applies a series of stripes with thicknesses in equal percentage steps, to permit single-drawdown exploration of the widest practicable application range. In addition to the hiding level of the coating, it also facilitates examination of the effect of film thickness on drying speed and surface uniformity, allowing a quick characterization of the essential features of the coating. The individual stripes are identified by "INDEX" numbers (20 to 48) engraved on the instrument, and also printed on the Form 23B Logicator Chart designed for use with this applicator. The Index Numbers are in equal numerical steps corresponding to increments of approximately 20% in notch clearance, film thickness and spreading ...