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Robert D Feinman

Using Blur for Creative Adjustments



In most cases I try to make adjustments to an image that correct for deficiencies caused by the limitations of exposure, scanning or the film characteristics.

Sometimes, however, there is a need to capture the intent rather than a literal image.

The image shown is the original scan. This is a picture of a very old stone cross in front of the chapel at the English estate, Lanhydrock.

The coloration makes it blend into the church and it is hard to see. The motivation for taking the pictures is unclear.

original
  Original Image
This version shows the image after applying some perspective adjustment to correct for the camera tilt.

In addition curves was applied to brighten the image foreground and to darken the sky using masks.

These techniques are discussed in the linked tips.
after perspective
After Perspective and Brightness
Using the magnetic lasso we selected just the cross and copied it to a new layer.

In other cases it might be easier to select by color range or by use of the magic wand.
just cross
Selecting the Cross
We next duplicate the background image and apply a Gaussian blur. The amount is determined by eye taking into account the size of the final image.

For this image a print of about 11x14 inches (about A3) was the goal so the blur radius was about 50 on a 300 dpi image. This gives a radius of about 1/6 inch (4mm). This is quite blurry if seen in a photographic enlargement.

We fix this in the following steps.

gaussian blur
Gaussian Blur
This shows the layers after the addition of a masked curve at the top to make some extra brightness adjustments to just the cross.

Notice the mask on the top layer so that the associated curves adjustments do not affect anything else in the image.
screen shot
The Arrangement of Layers
In this view we have moved the editing focus to the blurred layer. Notice that the Opacity is set to 55% at the top of the panel.

By keeping the sharp version below the blurred copy and changing the opacity we can control the degree of the effect.

Small changes are immediately visible on the full-size image. Just having one layer and blurring would require a lot of trial and error to get the desired effect.

opacity change
Adjusting the Opacity
This is the final image. The cross is sharp and stands out as intended.

The blurred background lends a dreamy quality that is in harmony with the English Victorian countryside.

Click here for a larger view.

This technique of mixing sharp and blurred parts of an image is very popular with portraitists. Commonly the eyes are kept sharp and the rest of the face is blurred slightly. This flatters the sitter and obscures wrinkles and other skin problems.

Other ideas are blurring using a gradient mask which would simulate the effect of the Scheimpflug rule used with view cameras.

You can find many examples in advertising to direct the viewer to the product. In most cases the blurring is much more subtle.
final image
Final Image
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© 2005 Robert D Feinman