TLR Digital Noise Reduction is a set of Photoshop actions for reducing noise in digital images.
All digital cameras introduce noise into the images they record. Expensive DSLRs do a better job of processing noise than inexpensive digicams, but even images from the $8000 Canon 1Ds MkII sometimes show visible noise, especially when you shoot at higher ISO settings.
There are some well-known ways of handling noise. Most involve blurring the channels in the image or averaging pixel values. Photoshop also includes some Noise filters: Despeckle, Dust & Scratches, etc.
The actions in TLR Digital Noise Reduction use a more sophisticated method of noise reduction. The start with a mask to preserve image details. A duplicate of the image is converted to 8-bit grayscale to speed mask generation. The mask is used to preserve image detail. Everything else in the image gets an application of digital noise reduction.
There are ten progressive levels of digital noise reduction available in the TLR Digital Noise Reduction action set. There is also a manual action where you control the settings from mask generation to noise reduction parameters.
The image above is a 200% cropped portion of a Canon 10D RAW file of a water lily (Kanapaha Garden, Gainesville, FL). Water is an image feature that often shows noise. TLR Digital Noise Reduction removes the noise with appreciably softening image detail.
The perfect companion to TLR Digital Noise Reduction is the TLR Edge & Surface Masks action set (another free download). You can use the surface mask actions in TLR Edge & Surface Masks to further restrict noise reduction away from image details. The action sets use complementary techniques for generating masks that will provide excellent protection for image details.
Adding a surface mask will prevent fine image details from softening.
The actions in TLR Digital Noise Reduction work non-destructively with your images. All of their work is done on layers. You have lots of flexibility, too. The layers have less than 100% opacity. Yuo you can adjust the effect later - very handy for when you get ready to output your images.
The actions work with RGB, CMYK, L*a*b, and Grayscale images. They are compatible with Photoshop 7 and beyond. In Photoshop CS and beyond, the actions are placed in a Layer Set/Group to make them easier to manipulate.
Depending on the strength of digital noise reduction selected, there will be two layers or three. This is different than most noise reduction action sets, which reduce noise but do nothing to restore image details. Levels 3-4, 5-6, 7-8, and 9-10 are paired. They use the same sharpening settings. Levels 3, 5, 7, and 9 include a "Restore Fine Details" layer and Levels 4, 6, 8, and 10 do not. Including a "Restore Fine Details" layer will reduce the noise reduction slightly while preserving more of the original image sharpness.
The noise reduction layers have a default opacity of 85%. The layers for preserving image details have their opacity set to 65%. Feel free to adjust these settings to increase noise reduction or restore more of the original image.
Reduction of chroma noise is another sophisticated feature of the TLR Digital Noise Reduction actions. Three progressive strengths of chroma noise reduction are applied by making a duplicate image that is converted to L*a*b mode where chroma noise can be more effectively removed (and with less softening of image details).