How to Apply a Smart Filter to Multiple Layers in Photoshop

Every beautiful Adobe Photoshop effect is the result of editing magic on multiple layers. Layers, like simple transparent sheets, can be shuffled and shaped together. But did you know you can use a smart filter, instead of a regular filter, on multiple layers for even more interesting effects?

A regular filter alters the pixels in a layer permanently. A smart filter applies a filter effect to layers non-destructively. This is a huge time-saving step. Let's see how you can use a smart filter on multiple layers and retain the power to make edits at any time.

How to Apply a Smart Filter to Multiple Layers in Photoshop

Go to the Layers panel and select all the layers you want to apply a filter to. Go to Filter in the menu. You will notice that none of the filters are available to you -- except one. Choose Convert for Smart Filters. Photoshop will tell you that smart filters are re-editable and the layers will become a smart object. Click OK and choose any filter. For instance, I selected "Oil Paint" from the Filter Gallery. If you need to change something in one of the layers before or after applying the filter, click on the thumbnail of the smart object layer. The group of images opens in a second window. Each image is back in its own layer. Select the layer you want to edit. Press Ctrl + S (Windows) or Command + S (Mac) to save the change. Close the second window. You will notice that the smart object in the first window has been updated with your edits.

The Smart Filter allows you to apply a filter in one step as if the selected layers are all flattened. The Smart Filter considers the grouped photos as one image and applies the filter to the pixels accordingly.

Smart Filters are non-destructive. You can adjust, remove, or hide a Smart Filter any time. But Adobe does say this:

"You can apply any Photoshop filter (that has been enabled to work with Smart Filters) — except for Lens Blur, Flame Picture Frame, Trees, and Vanishing Point—as a Smart Filter. In addition, you can apply Shadow/Highlight as Smart Filters."

Smart filters are really simple but powerful. You can change blend modes, use filter masks, or just tweak the filter settings for cool effects. And you won't lose any pixels!

What is your favorite way to use smart filters?

Basic Sharpening in Photoshop

Basic Sharpening in Photoshop

Unsharp Mask

There are several ways to sharpen in Photoshop, the most useful of which is usually the Unsharp Mask filter (Filters, Sharpen, Unsharp Mask.)

Threshold

The unsharp mask tool has three parameters, Amount, Radius and Threshold. The threshold setting is used to set where in the image the sharpening will occur. At zero the whole image will be sharpened. Otherwise the value sets a minimum level between adjacent pixels; if the difference in values is less than this, sharpening will not occur. For most purposes a value 0-10 is used, but higher values will help to avoid the creation or emphasis of unevenness in smooth areas of tone.

Radius

Radius is used to set the amount and extent of the sharpening. We can set decimal fractions values, such as 0.3, in this box, although when sharpening an image for print output, rather larger values will be needed. Overlarge values will give visible halo effects around edges. A small degree of halo formation is essential to get the sharpest possible effects in print (either from inkjet printers or from repro) but should be avoided if possible for work on screen.

Amount

The Amount setting largely seems to act as a multiplier for the radius. If you are using the Unsharp Mask filter for 'creative sharpening' it will most normally be in the range 60-150%, but when applying 'output sharpening' for print you may need rather higher values.

Unsharp Mask: Luminance

Some people prefer to use unsharp masking not on the RGB image, but to convert this to a LAB image and sharpen only the lightness channel. The image is then converted back to RGB. This can avoid the problem of colour artifacts which are sometimes generated when sharpening.

Unsharp Mask with Edge Mask

Even with careful tweaking of the Threshold value, unsharp masking tends to increase noise in areas of relatively smooth tone. Generally you want to sharpen the edges while leaving these areas unchanged. This can be achieved by selecting the edge areas with a suitable selection mask before applying the unsharp mask filter.

1. Duplicate the image, using 'Image', 'Duplicate', accepting the default file name.

2. Change the duplicate to Gray Scale, using Image, Mode, Grayscale

3. If the image is 16 bit, change to 8 bit, using Image, Mode, 8 bit

4. Find the edges using Filter, Stylize, Find Edges.

5. Open the levels dialogue (Ctrl+L) and shift the white-point marker at the right under the histogram to the left until only edges are shown. You can also move the black point marker to the right to make the black edges more definite. The OK to apply

6. Use Filter, Blur, Gaussian Blur, adjusting the radius to keep the edges clearly visible but with soft edges - typically around 2 pixels, OK to apply.

7. Invert the image using Ctrl + I

8. Open the Levels dialogue (Ctrl+L) and again shift the white point marker to get clear whites, OK

9. Return to the original image, and 'Select, Load Selection' accepting the default name as a new selection.

10. Press Ctlr+H to hide the 'marching ants' and then use Filters, Sharpen, Unsharp Mask. For 'Creative Masking' choose relatively small values of radius, perhaps around 0.5-2 pixels, keep the threshold at zero and adjust the amount to get sharpness without significant halos. For Output sharpening for printers, try values of 1.5-4 pixels for the radius, viewing the image at 25% and making the effect slightly too noticeable on screen. OK to apply.

It would be better practice to carry out the sharpening on a layer, but this would double the final file size.

Unsharp Mask Filter

About the Photoshop sharpening filters

Use the Unsharp Mask (USM) filter to sharpen your images. The controls provided by this filter make it the best choice for sharpening. Although Photoshop also has the Sharpen, Sharpen Edges, and Sharpen More filter options, these filters are automatic and do not provide controls and options. You might use these filters for producing creative effects in your image.

Photoshop lets you sharpen your entire image or sharpen part of your image by using a selection or mask. Since the Unsharp Mask filter can only be applied to one layer at a time, you might need to merge layers or flatten your file to sharpen all image layers in a multilayered file.

Note: The name, Unsharp Mask, makes the filter seem like an unintuitive choice for sharpening an image. The term comes from a darkroom technique used in traditional film-based photography. The effect of a sharpened edge can be produced by sandwiching a photographic negative and a slightly blurred and underexposed copy negative in the enlarger. Then the photographic paper is exposed through the sandwiched negatives.

Using the Unsharp Mask filter

The Unsharp Mask does not detect edges in an image. Instead, it locates pixels that differ in value from surrounding pixels by the threshold you specify and increases the pixels' contrast by the amount you specify. So, for neighboring pixels specified by the threshold, the lighter pixels get even lighter and the darker pixels get even darker based on the specified amount.

In addition, you specify the radius of the region to which each pixel is compared. The greater the radius, the larger the edge effects.

Original image and Unsharp Mask applied

The degree of sharpening applied to an image is often a matter of personal choice. However, over-sharpening an image produces an unattractive halo effect around the edges.

Over-sharpening an image produces a halo effect around the edges.

The effects of the Unsharp Mask filter are more pronounced on-screen than in high-resolution output. If your final destination is print, experiment to determine what settings work best for your image.

To use Unsharp Mask to sharpen an image:

(Optional) If your image is multilayered, select the layer with the image you want sharpened. The Unsharp Mask can only be applied to one layer at a time, even if layers are linked or grouped. You can merge the layers before applying the Unsharp Mask filter.

Choose Filter > Sharpen > Unsharp Mask. Make sure the Preview option is selected.

Click the image in the preview window and hold down the mouse to see how the image looks without the sharpening. Drag in the preview window to see different parts of the image, and click + or - to zoom in or out.

Although there is a preview window in the Unsharp Mask dialog box, it's best to move the dialog box so you can preview the effects of the filter in the document window.

Drag the Radius slider or enter a value to determine the number of pixels surrounding the edge pixels that affect the sharpening. The greater the radius value, the wider the edge effects. And the wider the edge effects, the more obvious the sharpening.

Adjusting the Radius value depends on the subject matter of the image, the size that the image will be reproduced at, and output method. For high-resolution images, a Radius between 1 and 2 is usually recommended. A lower value sharpens only the edge pixels, whereas a higher value sharpens a wider band of pixels. This effect is much less noticeable in print than on-screen, because a 2-pixel radius represents a smaller area in a high-resolution printed image.

Do one of the following:

Drag the Amount slider or enter a value to determine how much to increase the contrast of pixels. For high-resolution printed images, an amount between 150% and 200% is usually recommended.

Drag the Threshold slider or enter a value to determine how different the sharpened pixels must be from the surrounding area before they are considered edge pixels and sharpened by the filter. For instance, a threshold of 4 will affect all pixels that have tonal values that are different (on a scale of 0 to 255) by 4 or greater. So, if adjacent pixels have tonal values of 128 and 129, they will not be affected. To avoid introducing noise or posterization (in images with fleshtones, for example), use an edge mask or try experimenting with Threshold values between 2 and 20. The default Threshold value (0) sharpens all pixels in the image.

If applying Unsharp Mask makes already bright colors appear overly saturated, convert the image to Lab mode and apply the filter to the Lightness channel only. This sharpens the image without affecting the color components.

Selective sharpening

You can sharpen part of your image instead of the entire image by using a mask or a selection. This is useful when you want to prevent certain parts of your image from being sharpened. For example, you can use an edge mask with the Unsharp Mask filter on a portrait to keep the facial skin soft looking but sharpen features like the eyes, mouth, nose, and outline of the head.

Using an edge mask to apply the Unsharp Mask only to specific features in a portrait

To sharpen a selection:

With the image layer selected in the Layers palette, draw a selection.

Choose Filter > Sharpen > Unsharp Mask. Adjust the options and click OK.

The image area within the selection will be sharpened, leaving the rest of the image untouched.

To selectively sharpen an image using an edge mask:

Create an edge mask.

There are many ways to create an edge mask. Experiment with the following method:

Open the Channels palette and select the channel that displays the grayscale image with the greatest contrast in the document window. Often, the green or the red channel will be the one you select.

Showing a channel with the greatest contrast

Duplicate the selected channel.

With the duplicate channel selected, choose Filter > Stylize > Find Edges.

Choose Image > Adjustments > Invert to invert the image.

Find Edges filter applied and image inverted

With the inverted image still selected, choose Filter > Other > Maximum. Set the radius to a low number and click OK to thicken the edges and randomize the pixels.

Choose Filter > Noise > Median. Set the radius to a low number and click OK. This averages the neighboring pixels.

Choose Filter > Blur > Gaussian Blur to feather the edges.

Note: The Maximum, the Median, and the Gaussian Blur filters soften the edge mask so the sharpening effects will blend better in the final image. Although this procedure recommends using all three filters, you can experiment using only one or two.

Choose Image > Adjustment > Levels and set the black point high to get rid of random pixels. If necessary, you can also paint with black to retouch the final edge mask.

Set the black point high in Levels to eliminate random pixels in the edge mask

In the Channels palette, Ctrl-click (Windows) or Command-click (Mac OS) the duplicate channel to make the edge mask a selection.

In the Layers palette, select the image layer. Make sure the selection is visible on the image.

Choose Select > Inverse.

With the selection active on the image layer, choose Filter > Sharpen > Unsharp Mask. Set the desired options and click OK.

Note: You can create an action to conveniently apply all the steps in the procedure.

Sharpen a photo

How To Tip:

Sharpen a photo using the Unsharp Mask filter.

In the Layers palette, select the layer containing the image you want to change.

If you want to sharpen only a specific element or area in the image, create a selection marquee around the area you want to sharpen using the selection tools. The selection marquee limits the changes to that area. To soften the edge of the selection so the changes blend in more naturally with the unselected areas, use the Feather command (Select > Feather).

Choose Filter > Sharpen > Unsharp Mask.

In the Unsharp Mask dialog box, make sure Preview is selected. Then position the Unsharp Mask dialog box so that you can see most of the image.

Drag the Amount slider to the right to increase the contrast of the edge. For high-resolution printed images, an amount between 150% and 200% is usually satisfactory. Grainy images usually require a lower setting.

Drag the Radius slider to the right to increase the width of the edge created by sharpening. If you set this too high, the edges will acquire obvious halos. A setting between 1 and 2 is often adequate.

Drag the Threshold slider to the right to increase the difference needed between shades before the filter sharpens the edge between them. A threshold of zero sharpens all pixels in the image. A high threshold number sharpens the edges only between significantly different shades. Values between 2 and 20 are usually acceptable.

Experiment with these three controls until you are satisfied with the results, and then click OK.

You can let Photoshop sharpen the image for you using the three other Sharpen filters. Choose Filter > Sharpen, and then choose one of these filters from the submenu: Sharpen, Sharpen Edges, or Sharpen More.

Retouching for Good or Evil with Photoshop’s Liquify Filter

Retouching for Good or Evil with Photoshop’s Liquify Filter

The fashion industry has long laid claim to Photoshop’s Liquify filter as its staple of image manipulation, but like many tools in post, it can be used for either good or evil. While it’s true there’s no end to the fun that can be had adjusting your buddy’s face or physique in post, the Liquify filter can also be used to nudge, exaggerate, or diminish selected features of underwater photos for surprisingly realistic results. Before we begin, let me add a disclaimer – these aren’t techniques I recommend for everyday use. Use them sparingly, and don’t let Liquify’s mad powers lure you to the dark side!

Select the layer you want to edit, and open the Liquify panel by choosing Filter>Liquify from Photoshop’s top menu bar.

Once in the Liquify panel, set some brush options.

Liquify Brush Options

Brush Size

Sets the width of the brush you’ll use to adjust the image. Always select a brush size that’s slightly bigger than you think you need, and change the brush size often. Different parts of the image will need different brush sizes.

Brush Density

Controls how a brush feathers at the edge. An effect is strongest in the center of the brush and lighter at the edge. Use high density to get more bang for the buck out of the brush.

Brush Pressure

Sets the speed at which distortions are made when you drag a tool in the preview image. Using a low brush pressure makes changes occur more slowly, so it’s easier to stop them at exactly the right moment.

Brush Rate

Sets the speed at which adjustments are applied when you keep a tool stationary (click and hold) in the preview image. The higher the setting, the greater the speed at which distortion is applied.

Stylus Pressure

Uses pressure readings from a stylus tablet. (This option is available only when you are working with a tablet.)

Before you start to Liquify, protect any areas that should remain undistorted.

Protecting Selected Pixels

The Freeze Mask Tool and Thaw Mask Tool Work in tandem throughout the Liquify process. You can freeze areas that you don’t want to modify or thaw frozen areas to make them editable again. By freezing areas of the preview image, you protect those areas from changes. Frozen areas are covered by a red mask that you paint using the Freeze Mask tool. Painting with the Thaw Mask tool unfreezes them.

Liquify away!

Need-to-Know Distortion Tools

Though the Liquify filter offers an array of tools, you really only need to know a few for underwater photography. These tools mash the pixels around, letting you push, pull, pucker or bloat specific areas of your image.

The Forward Warp Tool

Lets you “fingerpaint” pixels into place, by clicking and dragging in the desired direction. In this shot of a grouper, I’ve used the Forward Warp tool to open the mouth, emphasize the eye, and pull the dorsal fin upright.

The Pucker Tool

Sucks pixels inward toward the center of the brush as you click and hold or drag in the desired area of the image. It’s not unusual to get a somewhat comedic “sock puppet” effect when shooting sharks or other large critters close up with a fisheye lens. Since “sock puppet” isn’t exactly the phrase you want springing to mind when looking at sharks, the Pucker tool is a great way to address fisheye distortion locally (on specific areas of the image).

The Bloat Tool

Expands pixels outward from the center of the brush as you click and hold or drag in the image. In this jawfish shot, I was able to widen the already open mouth and emphasize the eyes. The Bloat tool is also great for slightly enlarging the eyeballs of critters like shrimp and crabs, where sometimes they’re hard to discern.

Finesse your edits using reconstruction tools. Less is more!

Reconstructing Distortions

The Reconstruction Tool reconstructs specific areas of your editing. Brushing over an edit gradually backs off the original intensity.

Clicking the “Reconstruct” button in the Brush Reconstruct Options panel reveals a Revert Reconstruction slider that lets you gradually modify edits across the entire image. Move the slider to the left to incrementally walk back all your edits at once.

Clicking the “Restore All” button in the Brush Reconstruct Options panel completely undoes all changes.