From Manufacturer
The 4 x 5.65" Cinema Black Alchemy Filter from Tokina is a diffusion filter designed to affect resolution and contrast with a slight boost of halation to light sources. This is a combination of the Black Supermist 1/2 with a variable strength of SoftRes filter depending on the strength selected. Black Alchemy diffuses in a pleasing manner by reducing high frequency details like wrinkles and blemishes in skin, while raising black levels slightly and adding halation bloom to light sources. Black Alchemy is made of fine black and white color particulate that is bonded between two pieces of Schott B270 Optical Glass which exceeds 4K resolution capability. The particulate ranges in size from slightly smaller than a pixel to slightly larger than a pixel size, to alter incoming light, which creates the pleasing reduction in resolution and a slight raise in contrast with bloom to highlights. The 1/2 strength is reserved for a strong dramatic effect or dream sequence type scene.