Batch and Direction Sensitivity
Color Selection Tips – Why it is important to consider batch and direction sensitivity
Metal is a versatile roofing and siding material that offers a wide variety of vibrant color options. This color can be used for a vast range of purposes, from memorable design accents to elevated corporate identity. When selecting a color, an important element to consider is if it is batch or direction sensitive. Failure to properly manage these colors can lead to solution imperfections that may detract from the installed visual appearance of a structure.
Most solid metal colors do not exhibit batch or direction color sensitivity. Common colors are solid hues such as whites, browns, greens, and blues found on manufacturer standard color cards. Batch and direction sensitive products are primarily associated with premium or specialty products including micas or metallics, translucent resins and printed designs. Designers and specifiers may select these premium finishes for enhanced visual appeal, color depth, or design distinctiveness.
Why are these colors sensitive?
Batch or direction sensitivity can occur for several reasons, including pigment design, paint system composition, or the production process. Mica or metallic products use specially formulated pigments that are added to standard paints to create a light-catching effect. Individual mica pigment particles are flat, allowing for light to reflect at various angles, creating a distinctive visual appearance. This creates additional depth and dynamic interaction with light. Common micas include silver, bronze, champagne, and copper tones. As these pigments are flat, it is difficult to control the way they fall and appear within the paint. This leads to variations between batches and color which changes based on viewing direction.
Translucent resins provide additional color depth, as they allow the distinctive surface of the base metal to be somewhat apparent. These systems do not have a primer, and this makes them more sensitive to the composition of the base metal underneath, and the thickness of the resin applied. These properties vary slightly between batches.
Printed designs such as rust, copper patina, or woodgrain are used to evoke weathered metal or alternate materials, but with the reassurance of a traditional warranty. These products are manufactured by applying the print over the top of a solid base color using applicator rolls. This process is highly sensitive to production inputs, such as the pressure of the applicator roll, line speed, and paint viscosity, leading to slight batch-to-batch variation.
Metal finishes are produced using narrow production tolerances and must pass color-specific acceptance tests. As a result, the degree of color variation between these sensitive colors is relatively minimal. However, when installed directly next to one another or when illuminated by bright light, the color variance becomes pronounced. These sensitivities are most visible when the product is used on a flat surface such as a flush panel, or in a highly visible location that interacts with light. The two examples below demonstrate the visual impact of failing to account for this during installation.
Strategies for success
Validate if the desired color is batch or direction sensitive. Guidance is commonly published within product literature, or on a product manufacturers’ color card. If this is ambiguous, contact the manufacturer.
Overcome batch mixing by accurately estimating the amount of material required for the job. This may include holding surplus material for anticipated building additions or unforeseen trim pieces until the job is complete, ensuring the material (coil number) or batch number, is recorded when stored.
Ensure the installer appropriately stages material, and mounts panels in a singular direction. Many metal products feature asymmetric designs that make installation in a singular direction straightforward, but this does not apply to all products. Where this issue is most prevalent is when flat stock is used to manufacture trim and accessory pieces either by the roofer or on the job site. Some product manufacturers assist this process by providing directional arrows on the strippable film applied to the metal. Strippable film refers to a plastic film applied to the metal to prevent transport and installation damage. This film is removed once the metal is installed. Alternatively, some metal coaters can print directional arrows on the backside of the painted metal surface to provide additional directional guidance.
For additional information about managing batch and direction paint sensitivities, contact your metal product manufacturer, or metal coater. You can also contact Ask Steelscape with any questions you may have about Steelscape metals.
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