The desired appearance of powder coated film depends upon the specific industrial application. While a glossy, mirror-like finish with a high distinctiveness of image (DOI) is required for automotive clear coat applications, much outdoor equipment and many household appliances require smoothly textured finishes that hide surface irregularities, fingerprints, and surface markings. This textured finish of powder coated film, often termed orange peel appearance, can be controlled by adjusting the chemical formulation and the physical properties of the powder and by optimizing the electrostatic application process. These adjustments allow a wide-ranging control of gloss and orange peel texture. The chemical formulation of the powder is often determined by the functional needs of the coatings: providing protection against corrosion, heat, UV radiation, and physical impact. In many cases where the formulation cannot be changed, the electrostatic spraying process for the powder can be adjusted to achieve the desired gloss and texture. In electrostatic powder coating, back corona on the deposited powder layer often causes defects in the film. However, if the electrical field intensity inside the powder layer is below the breakdown level, the adverse effect of back Corona can be avoided, thus improving the uniformity of the deposited powder layer. In the absence of back corona, increasing the high voltage applied to the corona gull improves both the smoothness and the glossiness of cured films. Back corona can be reduced by increasing the surface conductivity, of the powder. Increasing the relative humidity during spraying also decreases the roughness, since the augmented surface conductivity allows the powder layer charge to decay faster. The optimal relative humidity value for applying powder for uniform film thickness was found to be 60%; increasing humidity beyond that point led to surface degradation, possibly due to excess moisture trapped in the powder layer. While the surface smoothness increased, the glossiness did not vary significantly with the change in relative humidity. Another factor for film surface properties is the "hiding power" of the unevenness of the substrate surface. A rough substrate call be responsible for a rough film surface when film thickness is less than 25 mum. It was found that films 40 to 50 pin thick can successfully cover scratches of about 20 mum depth on the substrate. Typical values of film waviness varied from 1.5 to 3 mum, and film roughness varied from 0.2 to 0.4 mum for epoxy film with 60 to 65 mum thickness.