Glare Effecter is a computer graphics tool to express and render the brightness of the light source. It is consisted of flare and streak. Flare is diffusing light surround the light source and streak has a light trace. The purpose of this study is to confirm the glare effect of streak with luminance gradients. Our comparative experiments between flare image with diffusing luminance and streak with luminance gradients showed the amplifier effects of brightness. Streak amplified the glare effect of flare in both condition of back light, low luminance (#00) and high luminance (#5A). In former condition the contrast effect between light luminance and back luminance amplified the glare effects. In another case, the self luminosity of glare (Zavagno: 1999) occurred around the adjacent area of streak and flare affected brightness perception and made the glare more bright.