Techniques are disclosed for removing blemishes from a digital image by detecting pixels containing the blemishes and replacing or blending those pixels with other pixels in the image that have a relatively low probability of containing a blemish. A standard pixel mask includes a user-selected region of the image; an extended mask extends beyond the user-selected region; and a minimal output pixel mask corresponds to the user-selected region. The minimal mask increases the transparency of some regions in the standard mask while maintaining the opacity of the standard mask in the blemish areas. Colors in the extended mask are weighted and clustered, and pixels in the minimal mask are assigned varying shades of transparency as a function of the color frequency. A blemish removal algorithm is applied using the minimal mask, with semi-transparent regions receiving a blend of source and patch pixel colors according to the level of transparency.