Realistic skin blemish healing in portraits

[tomczak]

Blurring can be used to reduce skin imperfection in portraits (Bilateral Sharpen and Noise Reduction are especially useful for that), but the results could look 'plasticy' due to obliteration of high-frequency details, such as skin pores. One possible technique to avoid it is to:

1) Blur blemishes (e.g. with NR transform)
2) Composite the original with its blurred version, in Low Pass mode - increase the blur radius in Low Pass to preserve progressively courser textures from the original image.

A variation of this technique is to select the repair areas by opening interactive Mask Tool and painting the 'repair mask' on one of the input images, while keeping the Composite transformation dialog open and observing changes in Auto Preview. It's a bit akin to a magic brush and its kins.

Original

IMG_3320_Original.jpg (24.83 KiB) Viewed 4682 times

Blurred

IMG_3320_Blurred.jpg (12.15 KiB) Viewed 4681 times

Original + Blurred (Low Pass)

IMG_3320_LowPass.jpg (23.12 KiB) Viewed 4679 times

p.s. this image is oversaturated and has the red channel (inadvertently) blown in several areas - while not an ideal example, the technique seem to reduce the appearance of R-clipped areas somewhat as well.

[tomczak]

Somewhat similar results can be obtained in Bilateral Sharpen, with Sharpen Factor set to zero.

Use the Blur Threshold to limit blurring of hard edges - use Sharpen Threshold to prevent blurring of fine textures (e.g. skin pores).

Both techniques rely on smoothing mid-frequency blemishes, while using lower and upper thresholds to preserve both: major edges and high-frequency textures.

I find the appearance of the first technique (i.e. Lowpass Composite) more pleasing to the eye.