Sometimes an image suffers from staircasing edges or the jaggies, as in Figure 1. There are two methods I use to fix this. The first is using the Smudge tool at 50% opacity and drawing around the staircased edges, as in Figure 2.
Figure 1. The image before the Smudge tool
Figure 2. Using the Smudge tool to smooth out the staircasing edges
If the object lines are straight, I use my Shift key and mouse clicks to make my way around the object. You may have to use the Smudge tool and go back and forth over the area edge until the desired effect is created. Play around with your opacity settings on the Smudge tool. I usually start off with 50% opacity and go from there. The Smudge tool softens the edges of the object. You may want to add some noise to these areas when you have completed the Smudge tool corrections.
Another option is to use the Clone tool to fix jagged edges, like the ones in Figure 3. Set the tool to a very low opacity, typically 20 or 30%, and then brush along the edge of the object and massage the area back and forth until the area loses the jaggedness, as shown in Figure 4.
Figure 3. The area with jagged edges before the Clone tool brushing
Figure 4. The area after the jagged edges have been cloned and massaged with the Clone tool brushing
When employing this technique, change the position of the brushes often so you don't get any repeat patterns. Again, as with other methods described here, add noise to the area to break up the extreme, unnatural smoothness of the brushing.
Fixing a Grainy Image
One option for dealing with a grainy image is to look at the various color channels and see if one of the channels is causing more noise then some of the other channels. The yellow channel is not typically anything to worry about because it is so light; it's the other channels you have to worry about.
For example, the image in Figure 5 has a very grainy area. It turns out much of that graininess is in the cyan channel. If you display the cyan channel, as in Figure 6, and add a Gaussian blur to that channel only, it dramatically helps the graininess. (You could also clone or brush only that one channel to get rid of the blur). This way, you don't soften the whole image by blurring all channels, just one channel. This effect can make a big difference and is worth a try, because you are blurring only one or two channels and you are not diminishing the quality of all channels. It also makes the blurring effect less noticeable. Figure 7 shows the final results of this technique.
Figure 5. Here is a grainy-looking area of an image
Figure 6. The cyan channel has the bulk of the grain
Figure 7. Final result of blurring the cyan channel only
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Note: Don't be afraid to soften or fix a second channel if blurring only the cyan channel doesn't quite do the trick.
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Figure 8. Draw a mask around poor-looking areas and shapes
Another technique I use to clear up grainy or blotchy areas is to redraw the area. I start this process by masking off the area that needs to be repaired, as in Figure 8.
Figure 9. I don't want to paint directly on my image, so I'll create a new layer for each newly painted section
Note: Take constant readings of the original color with the Eyedropper tool to ensure that you are brushing in the right color.
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Add a new layer and set its attributes to normal, as in Figure 9.
With your Brush tool, begin by brushing in color in an attempt to replicate what was there before. With my Eyedropper tool, take readings of the current shades of color that make up the area you wish to repaint. The idea is not to change the color or the way the area is shaded or shaped, just repaint it so that it appears smooth and looks as though it has a higher resolution. Think of it as repainting that old bicycle or car with a fresh coat of paint! Nothing nicer than a snazzy-looking fresh coat of paint!
With the Brush tool, repaint the area shape. Continue this process of making shapes with the Pen tool, making selections, and creating new layers. Take readings of the original color that makes up the shape, and then brush it in to try and match the original shape, but of course with a much smoother, refined look to it.
Figure 10. The original unpainted look of the image
An image that started out like Figure 10, when you have brushed the entire area, should look something like Figure 11.
This is a great way to fix an area that is in rough shape. It does take some practice, though, and you must constantly take readings to change the color that you are brushing in. Solid objects are easier to fix than complex shapes; you'll have to work up to them. As with any brushed-in surface area, you should add a small amount of noise to these areas. Adding noise helps break up any banding that may occur and reduces the overly smooth surfaces you have just created.
Figure 11. The final look of the painted-in shapes on the image
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