This week we are covering some of the filters. Over one hundred filters come pre-installed within Photoshop, and there are hundreds more that are available from commercial and free sources. Here are a few things that I would like to emphasize about filters:

The best way to work with most filters is by applying them to a Smart Object (Photoshop 2 course). The resulting Smart Filter is non-destructive and adds a lot of flexibility and capability. However, since in this course our use of filters is destructive and can only be applied to a single layer at a time, you typically want to apply it on a composite layer (or duplicate layer if the image has only one layer). Applying a filter on one of these layers has the additional advantage of allowing you to reduce the filter’s strength at any time by dropping the layer’s opacity. I also like the technique that we learned in Tutorial 12 of using the History Brush to selectively paint a filter effect onto a layer.
Be familiar with the Filter Guidelines at the beginning of Tutorial 14. Note that a selection can be used to control where a filter will be applied. When the textbook says that filters are typically resolution-dependent, it is referring to pixel dimensions, not ppi.
The Filter Gallery (not in the textbook)
- The Filter Gallery is available in the Filter menu. Select one of its 47 filters by clicking on a category, e.g. Brush Strokes, and then a thumbnail OR by clicking a filter name from the alphabetical list (no categories) in the pop-up menu located in the upper-right of the Filter Gallery dialog box. The thumbnails are useful for giving you an idea of what the filter will do. Once selected, the filter is applied in the large preview area and appears in the applied filters list on the right. The preview area can be enlarged by enlarging the Filter Gallery dialog box.
- Drag sliders and/or select options for the filter you selected. As you make changes, the image will update in the preview area. The Neon Glow filter and all of the Sketch filters except for Chrome and Water Paper are affected by the foreground and background colors in the Tools panel, which must be selected before entering the filter gallery.
- Do any of the following:
  - Choose another filter to apply. The effect from the previous filter will be replaced by this new filter.
  - Click the New effect layer button in the lower-right. It will duplicate the selected filter layer (highlighted in gray) and add it to the top of the applied filters list. You may then choose a filter to replace the duplicated filter. Repeat this procedure to keep adding filters. Only the Filter Galley lets you preview the result from applying multiple filters.
  - To rearrange applied filters, drag a filter layer to a new position in the applied filters list. Rearranging filters can dramatically change the results. The filter at the top of the list has the most effect.
  - To remove an applied filter, select it in the applied filters list and click the Delete effect layer icon in the lower-right.
  - To hide the effect of a filter, click on its eye.
  - When you’re satisfied with the results, click OK. Hidden filters are not applied.
The Clouds, Difference Clouds, and Lens Flare filters are available in the Render category of the Filter menu and are fairly straightforward. They can create some interesting effects that come in handy in certain situations, such as those described in the textbook.
Both the Clouds filter and the Difference Clouds filter randomly generate an interesting cloud-like pattern using the foreground and background colors in the Tools panel. Keep pressing Ctrl/Command-F until you get a pattern that you like. You can return to a previously-generated pattern by using the History panel.

The Difference Clouds filter is unlike the Clouds filter in the following two ways:
- It blends its cloud-like pattern with the pixels in the active layer using the Difference blending mode, which basically inverts the colors.
- Since it needs to use the pixels in the active layer as the base color for the blending mode, nothing appears in transparent areas. You’ll get error message if the active layer is entirely transparent.
The Lens Flare filter simulates the refraction caused by shining a bright light into the camera lens. A lens flare can occur naturally in such situations as the sun shining directly into the lens or the light from a camera flash reflecting off some glass and back to the camera. Although photographers often try to avoid such glares, adding a lens flare can make the image look more realistic or dramatic. This “flaw” can add interest, make an image have a certain believable imperfection, or be an interesting addition to a graphic design.
Blurring provides the opposite effect to sharpening. It smooths transitions at edges by averaging the pixel colors along defined lines in an image. Therefore, a blur filter can be used to smooth facial skin in a portrait or to apply the Tone and Sharpen design principle by softening the background.
The Motion Blur filter can be used to make it look like the camera or the subject was in motion when the picture was taken. The filter's effect is analogous to photographing a moving object with a long exposure The filter is particularly useful if you first select the moving object or its background.
The Liquify filter makes it easy to hand-manipulate areas of an image in some interesting ways. It is one of my favorite filters since it can make very practical improvements as well as create some really weird stuff. Therefore, on a portrait, you can use it for either good or evil. You’ll make use of Liquify in the last homework assignment for your You Look Marvelous Project. Microsoft Word wants to spell it Liquefy, but Adobe thinks otherwise.
Some Liquify tools
- Forward Warp tool pushes pixels forward as you drag the mouse. It is good for such things as lifting the corners of someone's mouth into a smile, reducing ear lobes, reducing a nose profile, etc.
- Reconstruct tool is similar to the History Brush tool. Use it to paint over an area that you want to revert to its original state or where you want to reduce the effect of previous changes. It doesn’t work on frozen areas.
- Smooth tool removes the waviness in the mesh without affecting its overall shape. It works in a similar way to the Reconstruct tool, but it averages out the unsightly artifacts rather than reverting to the original image.
- Twirl Clockwise tool rotates pixels clockwise as you hold down the mouse button or drag. To twirl pixels counter-clockwise, hold down the Alt or Option key. It continues to work as you hold down the mouse button. It can be useful for a graphic design.
- Pucker tool moves pixels toward the center of the brush area as you click the mouse button or drag. When the mouse is held stationary, use a series of single mouse clicks; otherwise, it works too fast if the mouse is held down. This tool is useful for reducing the size of ears, lips, and noses.
- Bloat tool moves pixels away from the center of the brush area as you click the mouse button or drag. It works like the Pucker tool, but with the opposite effect. It is useful for enlarging eyes, lips, and balloons.
- Push Left tool is good for body sculpting, such as reducing a waist or adding It pushes pixels left in relation to the direction of the brush movement. So if the brush stroke is from left to right, it pushes pixels up. Keep the crosshairs (+), the center of the brush, just outside of the pixels that you want to push. It helps if the background pixels are nondescript since they tend to get distorted.
- Freeze Mask and Thaw Mask tools – the former will freeze an area of the image to protect it from further changes, while the latter will unfreeze anything frozen.
- Face Tool automatically identifies faces, eyes, noses, mouths, and the face shape and gives two methods for adjusting them. It works best on facial features facing the camera.
- One method lets you manipulate the facial features directly on the canvas. When you hover the mouse pointer over the eyes, nose, mouth, and the face outline, it displays handles that can be dragged to change the size and shape of that feature. For example, you can increase the distance between the eyes or make the person smile more.
- The second method uses the sliders in the Face-Aware Liquify area of the Properties panel. Expand this area and select the face with which you want to work. Expand the categories, such as Eyes, that you want to adjust and drag the sliders.
- Most changes to the facial features are applied symmetrically so if one side of the mouth is widened the other side widens automatically. However, changes made to an eye are applied independently if the appropriate link icon is not clicked in the Eyes section.
- For more information, visit the Use the Liquify filter topic in the Photoshop User Guide.
Brush Tool Options
As with the tools in the Photoshop Tools panel, each Liquify tool remembers how its options were set in its previous use.
- Size (1-15000)
  It sets the width of the brush
- Density (0-100) (not in textbook)
  It controls how strongly the tool works near the edge of the brush. It is analogous to Hardness for the Brush tool - a harder Brush applies more paint at its edge.
- Pressure (1-100)
  It sets the strength at which a distortion is made. Using a low brush pressure makes the tool easier to control, but then you may need to repeat the stroke multiple times to get the effect that you want.
- Rate (0-100) (not in textbook)
  For the Smooth, Reconstruct, and Twirl Clockwise tools, it is used in conjunction with Brush Pressure to set the speed at which the tool works when the tool is stationary. When the tool is moving, Brush Rate has less effect on the result.
  For the Bloat and Pucker tools, there is no Brush Pressure so it alone determines how fast the tool works. It has a stronger affect when the tool is stationary.
  It is not available with Forward Warp, Push Left, Freeze Mask, and Thaw Mask tools.
- Pin Edges (not in textbook)
  When checked, pixels will not pull away from the outer edge of the image. Generally, a good choice.
Several choices are available for reversing changes made with the Liquify filter:
- Ctrl/Command-Z - to undo the last image change
- Alt/Option-Ctrl/Command-Z - undo step by step
- Reconstruct tool - to selectively paint away changes to the degree specified by Brush Pressure. It doesn’t reconstruct totally frozen areas or changes made with Face-Aware Liquify.
- Brush Reconstruct Options – they don't reconstruct changes made with the Face tool or to Face-Aware Liquify sliders
  - Restore All button - undoes all brush changes including frozen areas. Ctrl/Command-Z will undo this restore – therefore, it’s a good way to see the before and after results.
  - Reconstruct button – The Amount slider lets you specify the amount of restoration, where 0 means that everything not frozen goes back to the way it was at the beginning of this Liquify session.

Additional resources

Add Lens Flare To Your Image The Right Way by Thomas Ingersoll – a fairly advanced article on how to better use the Lens Flare filter.

Filter Gallery - a video (3:46 minutes, closed captioned) and written tutorial on using the Filter Gallery