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How to Evaluate Coating Quality Using Distinctness of Image (DOI) Index

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A highly glossy and smooth finish is what consumers look for in a high quality product and one barrier to achieving such finish is the orange peel effect. Orange peel is caused by incorrect formulation or poorly applied coating and reflected images viewed in such coating appear distorted. Orange peel reduces the quality of a product appearance and to reduce the amount of orange peel in high gloss coating, stringent evaluation is necessary.

Traditionally, orange peel is visually evaluated using panels with varying degrees of orange peel.  This method is time consuming and are subjected to individual judgment. To achieve an objective coating quality evaluation, the use of instruments such as Rhopoint IQ  and IQ Flex with measurement parameter like Distinctness of Image (DOI) would be helpful.

DOI is a measurement parameter developed to express orange peel numerically. It measures the clarity of the reflected images produced on a highly glossy coated surface by quantifying the way light is reflected around the specular angle. A coated surface and its reflected image get smoother and clearer as the DOI value increase.

To understand more about appearance measuring, write or contact us at 6563 5533 for a free consultation.

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