|History Brush Tutorial:
Figure 1; Pierre and northern lights before history brush retouching.
Setting Photoshop Preferences:
Open Photoshop. Go to the pull-down menus at the top of the screen. Go to Edit/Preferences/Performance–the only preferences you really need to set are in this dialog box:
Figure 2; preferences dialog.
Set Memory usage to the top of the ideal range-if you have a lot of RAM you can set it as high as 80% provided you are not running other programs that require memory. Set your History & Cache to: History States-50, Cache Levels-4, you can set this to as low as 2 if you have a powerful computer with a great graphics card and lots of RAM. If you notice that your computer is running slowly or having trouble re-drawing the screen image you will want to go back and reset the Cache Levels back to the default level.
Ideally your Scratch Disk should be set to an entirely blank internal drive. A USB connected external drive is not be fast enough for this and is not recommended. If you don’t have a second internal drive your Scratch Disk will be the “C” drive. Ideally your “C” drive will only store your operating system and applications, all other data should be stored on external hard drives–more than one always back up! The Scratch Disk is the memory that Photoshop uses for mid-term memory while it works on your images. Depending upon the size of the image and functions you are performing Photoshop may require several Gigabytes or even a couple of HUNDRED Gigabytes of memory! Whatever disk you select for your Scratch Disk should be relatively free of data.
Setting up and using the History Palette:
When CS5 comes out of the box the palettes on the right side of the screen are: Navigator, Color, Adjustment Layers. Click the little gray x in the upper right corner of the “Color” palette-don’t worry as a photographer you will almost never need it, if you do want it back simply go to the pull-down menu Window and click on the “Color.” Now go to the little icon boxes just to the left of the “Navigator” palette.
Click on the top box which is the “History” palette. You can drag the History palette anywhere you want to put it on the screen. I place it just below the “Layers” palette. The History Palette records all actions that we complete on an open image. It is not save-able, once the image is closed and reopened the History States begin with “Open.” See Setting Up Photoshop Preferences above for setting the number of History States recorded on the Palette. To undo an action simply highlight or click on the action above the unwanted action in the History State.
History Brush tool:
I have found that the history brush tool is the most used function that I use in Photoshop. In fact if Lightroom was to incorporate a history brush tool I may never use Photoshop again. As noted above to use the history brush you must first set-up your history palette.
All history brush functions must be done on the image background not a layer.
Go to the pull-down menu and select: Image/Adjustments/Curves. I like to use curves for most of my image adjustments because as I noted earlier I believe it applies the changes in the most natural manner, you could use any of the adjustment options in the pull-down. Looking at just the area you want to lighten, darken, increase or decrease contrast, change color or whatever you want to do, make the necessary adjustments on the curve dialog box (or other dialog box you have selected.) Now go to the bottom of the History Palette, the middle icon on the bottom of the bar is a “camera” click on this icon. Scroll to the top of the History Palette, you will notice that a new icon layer has appeared titled “Snapshot 1”. Click on the blank box to the left of the icon, this sets the “History Brush Source.” Scroll to the bottom of the History Palette, highlight by clicking on the last action BEFORE you made the Image/Adjustment correction. Now select the History Brush from the tool palette. Adjust the size and feather of the History Brush on the menu bar just below the pull-down menus. On the toolbar across the top of your screen set the opacity of the history brush to aprox 25%. The opacity setting is simply a starting point; different situations will need more or less opacity to blend whatever change you are attempting, experimentation will determine the exact opacity setting for each instance you use the history brush. You can now apply the changes to the image by simply brushing the color or density changes onto the areas you want to apply it. Changing the brush size and opacity settings will need to be done for personal preference and individual need. Any number of changes can be applied to the image before the “Snapshot” is History Brush Source selected.
Figure 3 shows the History Palette with the appropriate icons set.
Figure 4 shows the History Palette after several “snapshots” have been history brushed into the image–sometimes there will be a dozen or more “snapshots” created during the retouching of an image.
Figure 5 shows Pierre and the northern lights after history brush retouching to bring out the northern lights more.