Luminance/chrominance threshold sliders allow you to adjust the way how plugin detects image details and discriminates them for noise. Higher values make plugin suppress more noise at the expense of losing some image details. Lower values leave all image details at the expense of some more noise left.

Luminance/chrominance suppression sliders tell plugin to leave some small amount of noise in the image. Completely noise-free image may look unnatural because all real world images contain some small amount of noise. Specifying maximal suppression for luminance and chrominance noise (in decibels) lets you to leave some noise to make the image more lively and possible to retain some details that could be lost in the process of denoising.

Light/dark areas correction sliders enable to separately tune noise reduction in highlight and shadow areas. It is known that typical digital photos have more noise in shadow areas and less noise in highlight areas. By setting light areas correction slider to negative values you can lower the noise detection threshold in highlight areas and leave more details there. By setting dark areas correction slider to positive values you can suppress noise in shadow areas stronger. If you set these sliders to positive values and the noise reduction is still not enough – try increasing the luminance/chrominance suppression sliders – they constrain the maximal amount of noise suppression and you may want to increase it.