To always remove stains or dust from the exact same areas of several images the following workflow using Gimp may lead to satisfactory (but not perfect) results.

###Obtain despeckle mask

1. Take an image from an even grey background to reveal artifacts

^{Source: Wikimedia}

2. Select artifacts (using Select by Color-tool or manually)

The more you select here the more is going to be repaired later.

3. Convert selection to a path
4. Save this path as .SVG

###Despeckle from mask

1. Load image to enhance

2. Load path from above
3. Convert path to selection

4. Apply Heal Selection tool

_{Heal Selection: 10 px | All around | Random}

To always remove stains or dust from the exact same areas of several images the following workflow using Gimp may lead to satisfactory (but not perfect) results.

###Obtain despeckle mask

1. Take an image from an even grey background to reveal artifacts

^{Source: Wikimedia}

2. Select artifacts (using Select by Color-tool or manually)

The more you select here the more is going to be repaired later.

3. Convert selection to a path
4. Save this path as .SVG

###Despeckle from mask

1. Load image to enhance

2. Load path from above
3. Convert path to selection

4. Apply Heal Selection tool

_{Heal Selection: 10 px | All around | Random
To avoid artifacts from healing (see bottom right) deselect areas from step 3.}

To always remove stains or dust from the exact same areas of several images the following workflow may lead to satisfactory (but not perfect) results.

###Obtain despeckle mask

1. Take an image from an even grey background to reveal artifacts
2. Select all artifacts (using Select by Color-tool or manually)
3. Convert selection to a path
4. Save this path as .SVG

###Despeckle from mask

1. Load image to enhance
2. Load path from above
3. Convert path to selection
4. [Optional] feather selection
5. Apply Heal Selection tool

Work in progress - Screenshots will follow

To always remove stains or dust from the exact same areas of several images the following workflow using Gimp may lead to satisfactory (but not perfect) results.

###Obtain despeckle mask

1. Take an image from an even grey background to reveal artifacts

^{Source: Wikimedia}

2. Select artifacts (using Select by Color-tool or manually)

The more you select here the more is going to be repaired later.

3. Convert selection to a path
4. Save this path as .SVG

###Despeckle from mask

1. Load image to enhance

2. Load path from above
3. Convert path to selection

4. Apply Heal Selection tool

_{Heal Selection: 10 px | All around | Random}