An intensity filter for deep UV lithography enhances contrast and also therefore increases the resolution of patterned images by passing only intensities that fall within a specific minimum threshold value, resulting in a more exact aerial image replicating the mask image. The two fin groups cooperate to define a central hole in a center thereof and have a plurality of fins extending radially and outwardly from the central hole. The method comprises providing a sample, a culture medium, and the latent effervescent body. A fan wheel with a plurality of fan blades is associated with the lower frame.