Venus in Color. The bluish hue of Venus is an effect of the colorization technique used to enhance subtle contrasts in cloud patterns and indicates that this image was taken through a violet filter.Features in the sulfuric acid clouds near the top of the planet's atmosphere are most prominent in violet and ultraviolet light.he bluish hue of Venus is an effect of the colorization technique used to enhance subtle contrasts in cloud patterns and indicates that this image was taken through a violet filter.