As one becomes more experienced in the use of Photoshop for practical retouching one will realize the need and the advantage of one tool over another.
When I first introduce my students to the spot healing brush they think of it like its God’s finger coming down and magically fixing all of the problems they have on an image. It is not till the student learns the disadvantage of the spot healing brush and its club-like use as a tool that they begin to want more control and precision of something like the clone stamp. Lets explore the pros and cons of the different retouching tools.
The Spot-Healing Brush: brush based tool that will sample (do not use Option-Click, just click) pixels within proximity to the spot you wish to remove, and is best used for small dots, dust and micro blemishes.
Advantage: quick and simple, very easy to use when cleaning a scan or when getting rid of tiny black heads and white heads.
Disadvantage: can not be used on large areas because with will mush the texture together and create an odd dappled effect across your image. Can not be used near points of high contrast because it will bleed the texture together.
Tip: the size of the brush tip should be only slightly larger than the spot you are removing. Too large a brush tip and you will damage essential texture.
The Healing Brush: brush based tool that allows the user to choose specifically (by Option-Clicking) which texture is sampled and blended into the spot that you wish to remove. Works much like the clone stamp, but will blend pixel texture with current luminosity.
Advantage: allows you to choose a specific area that you wish to sample from for more control over blending. Can be used for a larger area of the image than spot-healing brush.
Disadvantage: Should not be used for very large areas because texture will take on an inconstant look and not flow well. Can not be used at points of high contrast, can not preserve sharp edges.
The Patch Tool: lasso based tool allows one to select a large area of texture and either drag that selection from one place to another to either relocate the texture to that spot or to use that spot as the source of the texture for the selection. The tool will then blend the texture with the edges of the selection and keep the luminosity of that area selected.
Advantage: can be used to blend texture of very large areas, helps maintain large areas of pixel texture.
Disadvantage: must be used upon an island of texture and tone, and can not be used upon an area of multiple tonal ranges that intersect with the marching ants of your selection, i.e. you can patch-tool a tree that lays on a blue sky, only if you first remove the bottom of the tree where the sky merges with the ground. If you do not, the color and tone will bleed from the ground into the sky.
Tip: before deselecting, use the quick keys Command-Shift-F to bring up the Fade option so that you can fade the blend to something that may be more pleasing.
The Clone Stamp: brush based tool that allows one to sample (using Option-Click) a specific area of pixels. The sample can be used for a 100% 1-to-1 copy of pixels that will fade onto the spot where the brush is clicked based upon the softness or hardness of the brush edges. The tool can also be controlled by the opacity of the brush or the blending mode of the brush.
Advantage: is used for making very specific and controlled retouches. Greatest advantage is that the user can use it to copy/clone edge texture and maintain a sharp edge and or edge contrast. Also that it can be used to blend and smooth texture by controlling the blending mode or opacity.
Disadvantage: takes more user control and one can easily damage texture and pixels with this tool.
Tip: try using a low opacity and soft brush to get used to using the tool
Dodge / Burn: brush based tool that allows the user to brighten or darken the tone of pixels with out destroying pixel texture. You can size down the brush to effect a specific pixel or small group of pixels, and adjust them here and there over the expanse of the image to have an impactful, yet subtle change of the image.
Advantage: can be used to effect subtle change and maintain pixel texture
Disadvantage: can effect color and saturation when used heavily in a specific area. To use effectively the tool must be used at very low exposures (1-8% exposure) so not to damage the image. The result is that it is a very slow tool to use.
Tip: (see my previous blog entry on Burn and Dodge - http://housetribeca.tumblr.com/post/77174506688/photoshop-tool-burn-dodge)
- Jeremiah Dart