Dust & Scratches

Fixing them

Clive R. Haynes FRPS

Using the Rubber Stamp / Clone Stamp Tool.

The most frequent method for dealing with dust, scratches and blemishes is by means of the Rubber Stamp / Clone Stamp tool.

It's advisable to create a new layer upon which to make the corrections as this keeps the original image intact.
To create a new layer (click on the New Layer icon at the base of the Layers palette or via Layer > New > Layer).

A useful tip is to tick 'Use All Layers' in the Options for the Clone Stamp tool. This, when you're using the newly created layer, enables you to directly clone upon this new layer without constantly having to activate the original image layer. If you wish, create additional new layers as and when needed. Additional layers give you the advantage of being able to dispose of them if errors are made.

Changing the Cloning Blend Mode Another useful tip is to change the 'blend mode' of the Clone Stamp as you work to suit the type of blemish you're dealing with. 'Darken' and 'Lighten' blend modes can assist with different sorts of blemish. Using 'Darken' the Clone Stamp tool darkens as it 'clones' into light areas image and therefore useful to darken a light toned scratch. Conversely, the 'Lighten' blend mode lightens as it 'clones' into dark areas of the image and so lightens a dark toned scratch.

Note: However, changing the 'Blend Mode' for the tool usually works best when 'cloning' on the same layer. The 'blend Mode' will not operate on a separate, empty layer (until it 'clones' over pixels on the layer), even if the 'Use all Layers' box is ticked as the blend mode needs something to blend with.
The technique is worth experimenting with as for the right image, this is a speedy solution.

Alternatives:
Blemishes can be sometimes difficult to fix with 'Clone Stamp' alone. Admittedly the 'Healing Brush' and the 'Patch Tool' introduced in Photoshop 7 are frequently better and speedier than the straightforward 'cloning'. However not everyone posses Version 7, so for 'non - V7' users, the alternatives described below may prove of interest:

These two methods, by using the 'Dust & Scratches Filter', work best when removing blemishes from areas of near non-texture - such as a cloudless blue or grey sky.

1 A Quick Method (Using the 'History Brush')

Open the image with the offending marks.

Enlarge/magnify a relevant area of the picture.

Go to Filter > Noise > Dust & Scratches

Select a Radius and Threshold level that just removes the blemishes > OK

Go to Filter > Noise > Add Noise > Gaussian > Monochromatic

Simulate the grain of the original image > OK

Go to the 'History' palette and click the box to the left of the 'Add Noise' history text - a brush and circular arrow icon appears. This creates a 'History Snapshot'.

Remaining in the History palette, return to 'Open' and click this section.

With the 'original' (blemishes and all) image displayed, go to the History Brush in the Tool Box (RH side, four down) and 'paint' over the blemishes with a suitable brush size - they will be 'filled' with the 'History Snapshot' you created.

2 A More Flexible Method

This is a slightly longer but preferred method which offers the advantage of being able to be ‘undone’ and set at different levels.

Open the image with the offending blemishes

Copy it to a new layer (above the original)

Switch off the layer you've just copied (click the 'eye' icon)

Make the lower layer (with blemishes and all) 'active'

Enlarge / magnify the relevant area to be treated

Go to File > Noise > Dust & Scratches

Adjust the sliders to make the blemishes disappear - the whole image will become blurred but only concentrate upon the blemishes

Return to the upper layer and make 'active'

Create a 'Layer Mask' for this layer - by clicking on the Layer Mask icon at base of layers palette (white circle in small grey square) - or go via Layer > Add Layer Mask > Reveal All route

Click in the layer mask rectangle (the white box to the right of the layer thumbnail image) to activate the layer mask function

Note re above step: If you don't activate the Layer Mask, you'll paint black on the image! When the Layer Mask is 'active' the paintbrush icon to the right of the eye icon on this layer will be replaced by a mask icon (white circle in small grey square). To come out of Layer mask operation to perform some other function on this layer, click the image thumbnail on this same layer and the brush icon returns

With the foreground colour set to black and the background set to white, choose a suitable brush and size and using 'black paint', paint over the blemishes. As you 'paint', the underlying layer will magically be revealed and this will fill the space with the blemish free image.

The new blemish-free areas so revealed may look 'too clean' and lack 'filmic quality'- to correct this add some noise to simulate grain. Of course, if you're using a digital camera then 'film grain' is not a problem you need to deal with.

With the lower layer (the one you 'removed the blemishes on) active, go to Filter > Noise > Add Noise > Gaussian (or 'uniform', if preferred) and adjust the noise level until it matches the granular structure of the original image

That's it!

This method has three big advantages over method 1

By using a Layer Mask, the strength of the effect can be varied by both brush pressure and layer opacity

It allows you to 'undo' the correction/painting that you've made at any time by swapping to white as the foreground

It allows you to set the amount of noise to more accurately match the grain of the film

CRHfoto@aol.com