Filters and their Uses

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The aim of the tutorial is to:
Is to give you an introduction to Filters. Filters are similar in all versions of PhotoShop.

Choosing a filter effect
The built-in filters are grouped into 14 submenus. In addition, any third-party filters installed appear at the bottom of the Filter menu.
Artistic filters
Choose a filter from the Artistic submenu to achieve a painterly or special effect for a fine arts or commercial project. For example, use the Cutout filter for collages or type treatment. These filters replicate natural or traditional media effects.

Colored Pencil Draws an image using colored pencils on a solid background. Important edges are retained and given a rough crosshatch appearance; the solid background color shows through the smoother areas.
For a parchment effect, change the background color just before applying the Colored Pencil filter to a selected area.
Cutout Portrays an image as though it were made from roughly cut-out pieces of colored paper. High-contrast images appear as if in silhouette, while colored images are built up from several layers of colored paper.

Dry Brush
Paints the edges of the image using a dry brush technique (between oil and watercolor). The filter simplifies an image by reducing its range of colors to areas of common color.

Film Grain
Applies an even pattern to the shadow tones and midtones of an image. A smoother, more saturated pattern is added to the image's lighter areas. This filter is useful for eliminating banding in blends and visually unifying elements from various sources.

Fresco
Paints an image in a coarse style using short, rounded, and hastily applied dabs.

Neon Glow
Adds various types of glows to the objects in an image and is useful for colorizing an image while softening its look. To select a glow color, click the glow box and select a color from the color picker.

Paint Daubs
Lets you choose from various brush sizes (from 1 to 50) and types for a painterly effect. Brush types include simple, light rough, light dark, wide sharp, wide blurry, and sparkle.

Palette Knife
Reduces detail in an image to give the effect of a thinly painted canvas that reveals the texture underneath.

Plastic Wrap
Coats the image in shiny plastic, accentuating the surface detail.

Poster Edges
Reduces the number of colors in an image (posterizes) according to the posterization option you set, and finds the edges of the image and draws black lines on them. Large broad areas of the image have simple shading, while fine dark detail is distributed throughout the image.

Rough Pastels
Makes an image appear as if stroked with colored pastel chalk on a textured background. In areas of bright color, the chalk appears thick with little texture; in darker areas, the chalk appears scraped off to reveal the texture. For more on the filter options, see Using texture and glass surface controls.

Smudge Stick
Softens an image using short diagonal strokes to smudge or smear the darker areas of the images. Lighter areas become brighter and lose detail.

Sponge
Creates images with highly textured areas of contrasting color, appearing to have been painted with a sponge.

Underpainting
Paints the image on a textured background, and then paints the final image over it. For more on the filter options, see Using texture and glass surface controls.

Watercolor
Paints the image in a watercolor style, simplifying details in an image, using a medium brush loaded with water and color. Where significant tonal changes occur at edges, the filter saturates the color.

Blur filters
The blur filters soften a selection or an image, and are useful for retouching. They smooth transitions by averaging the pixels next to the hard edges of defined lines and shaded areas in an image.
Note: To apply a Blur filter to the edges of a layer, be sure to deselect the Preserve Transparency option in the Layers palette.

Blur and Blur More (Photoshop)
Eliminate noise where significant color transitions occur in an image. Blur filters smooth transitions by averaging the pixels next to the hard edges of defined lines and shaded areas. The Blur More filter produces an effect three or four times stronger than that of the Blur filter.

Gaussian Blur
Quickly blurs a selection by an adjustable amount. Gaussian refers to the bell-shaped curve that is generated when Adobe Photo-shop applies a weighted average to the pixels. The Gaussian Blur filter adds low-frequency detail and can produce a hazy effect.

Motion Blur (Photoshop)
Blurs in a particular direction (from -360º to +360º) and at a specific intensity (from 1 to 999). The filter's effect is analogous to taking a picture of a moving object with a fixed exposure time.

Radial Blur
Simulates the blur of a zooming or rotating camera to produce a soft blur. Choose Spin, to blur along concentric circular lines, and then specify a degree of rotation; or Zoom, to blur along radial lines, as if zooming in or out of the image, and specify an amount from 1 to 100. Blur quality ranges from Draft for the fastest but grainy results; or Good and Best for smoother results, which are indistinguishable except on a large selection. Specify the origin of the blur by dragging the pattern in the Blur Center box.

Smart Blur
Precisely blurs an image. You can specify a radius, to determine how far the filter searches for dissimilar pixels to blur; a threshold, to determine how different the pixels' values should be before they are eliminated; and a blur quality. You also can set a mode for the entire selection (Normal), or for the edges of color transitions (Edge Only and Overlay). Where significant contrast occurs, Edge Only applies black-and-white edges, and Overlay Edge applies white.

Brush Stroke filters
Like the Artistic filters, the Brush Stroke filters give a painterly or fine-arts look using different brush and ink stroke effects. Some of the filters add grain, paint, noise, edge detail, or texture to an image for a pointillist effect.

Accented Edges
Accentuates the edges of an image. When the edge brightness control is set to a high value, the accents resemble white chalk; when set to a low value, the accents resemble black ink.

Angled Strokes
Repaints an image using diagonal strokes. The lighter areas of the image are painted in strokes going in one direction, while the darker areas are painted in strokes going the opposite direction.

Crosshatch
Preserves the details and features of the original image while adding texture and roughening the edges of the colored areas in the image with simulated pencil hatching. The Strength option controls the number of hatching passes, from 1 to 3.

Dark Strokes
Paints dark areas of an image closer to black with short, tight strokes, and paints lighter areas of the image with long, white strokes.

Ink Outlines
Redraws an image with fine narrow lines over the original details, in pen-and-ink style.

Spatter
Replicates the effect of a spatter airbrush. Increasing the options simplifies the overall effect.

Sprayed Strokes
Repaints an image, using its dominant colors with angled, sprayed strokes of color.

Sumi-e
Paints an image in Japanese style, as if with a wet brush full of black ink on rice paper. The effect is soft blurry edges with rich blacks.

Distort filters
The Distort filters geometrically distort an image, creating 3D or other reshaping effects. Note that these filters can be very memory intensive.

Diffuse Glow
Renders an image as though it were viewed through a soft diffusion filter. The filter adds see-through white noise to an image, with the glow fading from the center of a selection.

Displace filter
Uses an image, called a displacement map, to determine how to distort a selection. For example, using a parabola-shaped displacement map, you can create an image that appears to be printed on a cloth held at its corners.
This filter creates displacement maps, using a flattened file saved in Adobe Photoshop format (except Bitmap mode images). You can also use the files in the Plug-Ins/ Displacement Maps folder in the Photoshop program folder.
To use the Displace filter:
1. Choose Filter > Distort > Displace.
2. Enter the scale for the magnitude of the displacement.
When the horizontal and vertical scale are set to 100%, the greatest displacement is 128 pixels (because middle gray produces no displacement).
3. If the displacement map is not the same size as the selection, choose how the map will fit the image--Stretch to Fit to resize the map, or Tile to fill the selection by repeating the map in a pattern.
4. Choose Wrap Around or Repeat Edge Pixels to determine how undistorted areas of the image will be treated. (See Defining undistorted areas.)
5. Click OK.
6. Select and open the displacement map. The distortion is applied to the image.

The Displace filter shifts a selection using a color value from the displacement map--0 is the maximum negative shift, 255 the maximum positive shift, and a gray value of 128 produces no displacement. If a map has one channel, the image shifts along a diagonal defined by the horizontal and vertical scale ratios. If the map has more than one channel, the first channel controls the horizontal displacement and the second channel controls the vertical displacement.

Glass
Makes an image appear as if it is being viewed through different types of glass.You can choose a glass effect or create your own glass surface as a Photoshop file and apply it. You can adjust scaling, distortion, and smoothness settings. When using surface controls with a file, follow the instructions for the Displace filter. For more information about Glass filter controls, see Using texture and glass surface controls.

Ocean Ripple
Adds randomly spaced ripples to the image's surface, making the image look as if it were under water.

Pinch
Squeezes a selection. A positive value up to 100% shifts a selection toward its center; a negative value up to -100% shifts a selection outward.

Polar Coordinates
Converts a selection from its rectangular to polar coordinates, and vice versa, according to a selected option. You can use this filter to create a cylinder anamorphosis (art popular in the 18th century) in which the distorted image appears normal when viewed in a mirrored cylinder.

Ripple
Creates an undulating pattern on a selection, like ripples on the surface of a pond. For greater control, use the Wave filter. Options include the amount and size of ripples.

Shear
Distorts an image along a curve. Specify the curve by dragging the line in the box to form a curve for the distortion. You can adjust any point along the curve. Click Default to return the curve to a straight line. In addition, you choose how to treat undistorted areas. (See Defining undistorted areas.)

Spherize
Gives objects a 3D effect by wrapping a selection around a spherical shape, distorting the image and stretching it to fit the selected curve.

Twirl
Rotates a selection more sharply in the center than at the edges. Specifying an angle produces a twirl pattern.

Wave
Works in a similar way to the Ripple filter, but with greater control. Options include the number of wave generators, the wavelength (distance from one wave crest to the next), the height of the wave, and the wave type: Sine (rolling), Triangle, or Square. The Randomize option applies random values. You can also define undistorted areas. (See Defining undistorted areas.)
To replicate wave results on other selections, click Randomize, set the Number of Generators to 1, and set the minimum and maximum Wavelength and Amplitude parameters to the same value.

ZigZag
Distorts a selection radially, depending on the radius of the pixels in your selection. The Ridges option sets the number of direction reversals of the zigzag from the center of the selection to its edge. You also choose how to displace the pixels: Pond Ripples displaces pixels to the upper left or lower right, Out From Center displaces pixels toward or away from the center of the selection, and Around Center rotates pixels around the center.



Defining undistorted areas

The Displace, Shear, and Wave filters in the Distort submenu and the Offset filter in the Other submenu let you treat areas undefined by the filter in the following ways:

• Wrap Around fills the undefined space with content from the opposite edge of the image.
• Repeat Edge Pixels extends the colors of pixels along the image's edge in the direction specified. Banding may result if the edge pixels are different colors.
• Set to Background (Offset filter only) fills the selected area with the current background color.

Using texture and glass surface controls

The Conté Crayon, Glass, Rough Pastels, Texturizer, and Underpainting filters have texturizing options. These options make images appear as if they were painted onto textures such as canvas and brick or viewed through glass blocks.

To use texture and glass surface controls:
1. From the Filter menu, choose Artistic > Rough Pastels, Artistic > Underpainting, Distort > Glass, Sketch > Conté Crayon, or Texture > Texturizer.
2. For Texture, choose a texture type or choose Load Texture to specify a Photoshop file.
3. Drag the Scaling slider to enlarge or reduce the effect on the image surface.
4. Drag the Relief slider (if available) to adjust the depth of the texture's surface.
5. Select Invert to reverse the surface's light and dark colors.
6. For Light Direction, indicate the direction of the light source on the image.

Noise filters (Photoshop)

The Noise filters add or remove noise, or pixels with randomly distributed color levels. This helps to blend a selection into the surrounding pixels. Noise filters can create unusual textures or remove problem areas, such as dust and scratches, from an image.

Add Noise
Applies random pixels to an image, simulating the effect of shooting pictures on high-speed film. The Add Noise filter can also be used to reduce banding in feathered selections or graduated fills or to give a more realistic look to heavily retouched areas. Options include noise distribution: Uniform distributes color values of noise using random numbers between 0 and plus or minus the specified value for a subtle effect; Gaussian distributes color values of noise along a bell-shaped curve for a speckled effect. The Monochromatic option applies the filter to only the tonal elements in the image without changing the colors.

Despeckle
Detects the edges in an image (areas where significant color changes occur) and blurs all of the selection except those edges. This blur-ring removes noise while preserving detail.

Dust & Scratches
Reduces noise by changing dissimilar pixels. To achieve a balance between sharpening the image and hiding defects, try various combinations of radius and threshold settings. Or apply the filter on selected areas in the image.

To use the Dust & Scratches filter:
1. Choose Filter > Noise > Dust & Scratches.
2. If necessary, adjust the preview zoom ratio until the area containing noise is visible.

Drag the Threshold slider left to 0 to turn off the value, so that all pixels in the selection or image can be examined.

The Threshold determines how different the pixels' values should be before they are eliminated.

Note: The Threshold slider gives greater control for values between 0 and 128--the most common range for images--than for values between 128 and 255.

3. Drag the Radius slider left or right, or enter a value in the text box from 1 to 16 pixels. The radius determines how far the filter searches for differences among pixels.

Adjusting the radius makes the image blurry. Stop at the smallest value that eliminates the defects.

4. Increase the threshold gradually by entering a value or by dragging the slider to the highest value possible that eliminates defects.
Median

Reduces noise in an image by blending the brightness of pixels within a selection. The filter searches the radius of a pixel selection for pixels of similar brightness, discarding pixels that differ too much from adjacent pixels, and replaces the center pixel with the median brightness value of the searched pixels. This filter is useful for eliminating or reducing the effect of motion on an image.

Pixelate filters
The filters in the Pixelate submenu sharply define a selection by clumping pixels of similar color values in cells.
Color Halftone
Simulates the effect of using an enlarged halftone screen on each channel of the image. For each channel, the filter divides the image into rectangles and replaces each rectangle with a circle. The circle size is proportional to the brightness of the rectangle.

To use the Color Halftone filter:

1.Choose Filter > Pixelate > Color Halftone.
2. Enter a value in pixels for the maximum radius of a halftone dot, from 4 to 127.
3. Enter a screen-angle value (the angle of the dot from the true horizontal) for
one or more channels:

• For Grayscale images use only channel 1.
• For RGB images, use channels 1, 2, and 3, which correspond to the red, green, and blue channels.
• For CMYK images, use all four channels, which correspond to the cyan, magenta, yellow, and black channels.
• Click Defaults to return all the screen angles to their default values.

4. Click OK.

Crystallize
Clumps pixels into a solid color in a polygon shape.

Facet (Photoshop)
Clumps pixels of solid or similar colors into blocks of like-colored pixels. You can use this filter to make a scanned image look hand painted or to make a realistic image resemble an abstract painting.

Fragment (Photoshop)
Creates four copies of the pixels in the selection, averages them, and offsets them from each other.

Mezzotint
Converts an image to a random pattern of black-and-white areas or of fully saturated colors in a color image. To use the filter, choose a dot pattern from the Type menu in the Mezzotint dialog box.

Mosaic (Photoshop)
Clumps pixels into square blocks. The pixels in a given block are the same color, and the colors of the blocks represent the colors in the selection.

Pointillize
Breaks up the color in an image into randomly placed dots, as in a pointillist painting, and uses the background color as a canvas area between the dots.

Render filters
The Render filters create 3D shapes, cloud patterns, refraction patterns, and simulated light reflections in an image. You can also manipulate objects in 3D space, create 3D objects (cubes, spheres, and cylinders), and create texture fills from grayscale files to produce 3D-like effects for lighting.

3D Transform
Maps images to cubes, spheres, and cylinders, which you can then rotate in three dimensions.
Transforming objects in three dimensions
The 3D Transform filter lets you manipulate a flat, two-dimensional image as if it were a solid, three-dimensional object. Take, for example, a perspective photograph of a cereal box. You specify the corners of the box using a wire frame, and you can then manipulate the box as if it were a three-dimensional object. You can reposition the box, turn or rotate it, shrink or enlarge it, and change its field of view.

Transforming and manipulating objects
You can transform a two-dimensional object into a cube, sphere, or cylinder and manipulate it using wire frames based on that shape. Cylinders can include anything from simple objects, such as a can of soup, to shapes whose sides are lathed, such as a bottle or a lamp.
You can create and manipulate any grouping of cubes, spheres, and cylinders in the same image. For example, you can create and rotate a box, two balls, and a bottle together in the same image.

To add a wire frame:
1. Choose Filter > Render > 3D Transform.
2. Select one of these tools in the dialog box:

• Cube to map the image (such as a file cabinet) to a cubic surface.
• Sphere to map the image (such as a globe or ball) to a spherical surface.
• Cylinder to map the image (such as a can or bottle) to a cylindrical surface.

3. Drag to create a cubic, cylindrical, or spherical wire frame over the image preview.
Note: The anchor points should line up with the corners of the box, or the top and bottom of the sphere or cylinder you want to manipulate.

To move or reshape the wire frame:
1. Select the selection tool or direct selection tool in the 3D Transform dialog box.
2. Do either of the following:

• Drag an edge of the wire frame to move the entire frame.
• With the direct selection tool, drag an anchor point on the wire frame to move that anchor point.
Note: The wire frame turns red if you try to make a wire frame that would be impossible to re-create in three dimensions.

3. If you are creating a complex cylinder, do any of the following:

• To add an anchor point to a cylinder, select the add anchor point tool in the dialog box, and click the right side of the wire frame. For example, you can add an anchor point to more closely fit the cylindrical wire frame to a picture of a bottle.
• To change an added anchor point from a smooth anchor point to a corner anchor point and vice versa, select the convert anchor point tool , and click the point. A smooth anchor point creates a gentle curve when you adjust it; a corner anchor point creates a sharp corner.
• To delete an added anchor point, select the delete anchor point tool , and click the point.

4. For Field of View, enter a value between 1 and 130. Alternatively, drag the slider to the left to increase the apparent field of view, right to decrease it. This can make the wire frame fit the image better. If you know the field of view angle used to photograph the image, you can enter it here.

To delete a wire frame:

1. Select the selection tool in the 3D Transform dialog box.
2. Select the wire frame, and press Backspace (Windows) or Delete (Mac OS).

To manipulate the object in three dimensions:
do any of the following in the 3D Transform dialog box:

• To move the object, click the pan camera tool in the dialog box, and drag the object.
• To rotate the object in any direction, click the trackball tool , and drag the object.
• For Dolly Camera, enter a value between 0 and 99. Alternatively, drag the slider to the left to magnify the transformed object, right to shrink it. This has the same effect as if you were dollying, or moving, the camera further from or closer to the image.
• For Field of View, enter a value between 1 and 130, or drag the slider to the left to increase the apparent field of view, right to decrease it.

The 3D Transform dialog box previews only the active layer. As you manipulate an object in three dimensions, you can align it with the contents of underlying layers.
To align an object with an underlying layer:
1. Duplicate the layer with which you want to align.
2. Within the existing stacking order, place this duplicate layer directly under the layer you are transforming.
3. Merge the layer to be transformed with the duplicated layer.
4. With the Display Background option enabled in the 3D Transform options, manipulate the object on the layer.
5. When the layer is aligned, disable the Display Background option, and click OK.

Setting 3D rendering options
You can set the resolution and anti-aliasing of rendered images and specify whether to show the background from the original image in the 3D preview.

To set 3D rendering options:
1. Click Options in the 3D Transform dialog box.
2. Do any of the following:

• For Resolution, choose the quality of the rendered image. The setting has little effect on the image quality of cubes, but will produce smoother curved surfaces in cylinders and spheres.
• For Anti-aliasing, choose the level of anti-aliasing to apply to the rendered image.
• Select Display Background to include the portions of the original image outside of the wire frame in the preview and with the rendered image. Turn this option off to separate the transformed object from the original background.

Clouds
Generates a soft cloud pattern using random values that vary between the foreground and the background colors. To generate a more stark cloud pattern, hold down Alt (Windows) or Option (Mac OS) as you choose Filter> Render > Clouds.

Difference Clouds
Uses randomly generated values that vary between the foreground and back-ground color to produce a cloud pattern. The filter blends the cloud data with the existing pixels in the same way that the Difference mode blends colors. The first time you choose this filter, portions of the image are inverted in a cloud pattern. Applying the filter several times creates rib and vein patterns that resemble a marble texture.

Lens Flare
Simulates the refraction caused by shining a bright light into the camera lens. Specify a location for the center of the flare by clicking anywhere inside the image thumbnail or by dragging its cross hair.

Lighting Effects
Lets you produce myriad lighting effects on RGB images by varying 17 light styles, 3 light types, and 4 sets of light properties. You can also use textures from grayscale files (called bump maps) to produce 3D-like effects and save your own styles for use in other images.

Texture Fill
Fills a selection with a grayscale file or part of a file. To add the texture to the document or selection, you open the grayscale document you want to use as the texture fill.