Photo Retouch

Image Sharpening Using the Unsharp Mask Filter

noreply@blogger.com (Anonymous) — Fri, 19 Jul 2013 05:32:00 +0000

The Unsharp Mask, contrary to its name, actually sharpens your photo by elevating the contrast along the image’s edges. It’s pretty heady stuff that we don’t need to go into, all we need to know is that it works!

Step 1

Open up the image you want to work on, press Command-1 (PC: Control-1) or double-click the Zoom Tool to bring the image to 100%. You want the image to be at least 100%, so you can accurately and effectively see what the sharpening is doing, and know the threshold of the dreaded “halo effect.”

Step 2

Next click on the background layer, Right Click (or hold down command to bring up the Menu) and zip over to Convert to Smart Object. Then dive in to FILTER> SHARPEN> UNSHARP MASK. In the Unsharp Mask preview window, reposition your image so you can see the most prominent details.

Step 3

You have three variables to manipulate: Amount, Radius and Threshold. “Amount” is how much sharpening you’re doing, “Radius” is the reach of the filter, in terms of how far from an edge the sharpening extends. The value determines the number of pixels surrounding the edge pixels that get affected by the sharpening. So remember, the larger the Radius value, the wider the edges and the more obvious the sharpening… which is a big no-no. “Threshold” is the Strong Safety, so to speak, as in it protects you from other miscalculations or overzealousness!

Step 4

Set the Amount slider to a value to determine how much you want to increase the pixel contrast, between 100 and 200. The actual Amount of sharpening depends on the size and resolution of your image; so you can get away with an Amount of 100% on most images, but for hi-resolution images, you might want to try more than 130% to get a noticeable effect. Next increase your Radius to somewhere between 1 and 2 pixels, so you just start to see the halo around the edges (the telltale sign of manipulation… which you don’t ever want), then dial Radius back so the halo magically fades away… that’s your boundary, your sweet spot.

Step 5

Now that you have the sweet spot, lower the Amount by around 20 to 30 percentage points. For the final tweak, use the Threshold slider. Threshold sets a frontier in which the sharpening takes hold or doesn’t, and that’s based on the tonal value of the pixels that you’re looking to affect. The value establishes how different the sharpened pixels will be from the surrounding area before those pixels are affected by the filter. This is one of those “seeing is believing” options, so try between 2 and 20 for starters and then raise the Threshold to soften the sharpening until the image looks fabulous. Next, click on the Preview to see the before and after images. Since sharpening brings out some noise in the photo, you’ll want to change the blend mode to counteract this side effect; so change the Blend Mode on the layer you’re sharpening to Luminosity. This projects the image’s value, which is all important when looking to get rid of noise.

Before & After Image Sharpening

Background Changing

noreply@blogger.com (Anonymous) — Thu, 18 Jul 2013 05:24:00 +0000

Step 1

The first step is to switch to quick mask mode by pressing Q, and then select the Quick Selection tool by pressing W. In the Option bar, you’ll want to select Subtract From. Then change the tool’s brush tip size in the Options bar by using the Diameter slider or typing in a pixel size. You can always use the right bracket ] to increase the size, or the left bracket [ to decrease the size of the brush tip.

Step 2

You can choose "Sample All Layers” which generates a selection based on all the layers in the stack, instead of the currently selected one. Or choose Auto-Enhance, which reduces the jagged edges of the selection boundary. You can customize the edge refinement in the Refine Edge dialog box, which has options for Smooth, Contrast and Radius.

Step 3

Select the Brush tool in the Toolbox, and then press X to switch the paint output to Black. Since you're in Quick Mask mode, as you paint the rubylith overlay begins to cover the sky. Make sure that you paint out all the sky (zoom in and reduce the brush size if you need to for fine detail work); you might need to switch back to white paint to add back any portion of the Mask that you might have removed by mistake.

Step 4

Next press Q to exit Quick Mask. You'll have to invert the selection to finalize the extraction. You do this by pressing Cmd-Shift-I (PC: Control-Shift-I). Now you’re ready to replace the background. So just choose EDIT > CUT on the selection and it’s removed from the image. Now that you've cut out the overexposed sky, you need to bring the house to a new layer. So press Cmd-J (PC: Control-J) to copy the Extraction to a new layer, and then you can delete or just hide the original sky.

Step 5

Now here's where the magic happens. You need to open up your new background, in this case the vivid blue sky. Select the entire image then cut and paste it onto the house image. In the Layer Stack drop the Sky layer beneath the house, and without further ado, the picture has a new background (you can flatten the layer stack at this point to merge the foreground and background). The serious trick at this point is matching the lighting dynamics of the background with the foreground. You’ll need to make all manners of adjustments to make it look seamless.

Before & After Background Changing

Conclusion

Changing backgrounds is not a technique for the faint of heart, because it requires adjusting both the foreground element and the background element. It’s done more often than you think to put people in front of famous backdrops or on solid color backgrounds for editorial photography. It’s useful to know how to do this so you can “create” images and compositions. Think of all the fun you can have.

source : www.exposureguide.com

4 Fundamental Photoshop Skills

noreply@blogger.com (Anonymous) — Wed, 17 Jul 2013 04:03:00 +0000

Learn these essential tools and techniques and you'll be equipped for most common image enhancements

Text And Photography By Wes Pitts

Photoshop and other sophisticated image-editing applications can be overwhelming at first. The surest way to get comfortable working with them is to begin by mastering a few of the techniques you'll use most often. Once you've achieved some success with them, you'll have a solid foundation for exploring the rest of the software's tools. We've chosen four key skills that you'll need for the most common image enhancements to help you get started.

Make Selections
Making a good selection is more art than science, but you'll need both halves of your brain to master this fundamental Photoshop skill. Selections are essential for controlling which parts of your image are affected by the adjustments you make.

There are many tools and techniques for making selections in most image-editing applications. Photoshop offers a broad range of tools, from color selection to freehand tools and semi-automatic selectors.

Which Do You Choose?
I typically find I'll use several different selection tools to make a single selection, using each to add or subtract pixels to get the exact selection quickly. In this example, I wanted to see what my photo would look like if everything was black-and-white except for the stop sign. To do this, I needed to select the stop sign to isolate it from the rest of the image.

If the object or area you want to select is all one color, the fastest tool may be the Magic Wand. This tool selects all pixels of the sampled color, within a tolerance that you specify. The Magic Wand tool can be quick, but it takes some practice and it's not the fastest when you want to select an object that's multicolored or varied in tonality. Select > Color Range is a similar tool that lets you use eyedroppers to create selections by sampling colors.

Most often, I use the Lasso tools to make selections. The Freehand Lasso is just that, and follows your cursor wherever it goes. The Magnetic Lasso tries to find edges and snap to them as you trace around an object. This tool can be helpful when there's a clear, high-contrast edge around the area you're selecting. My favorite of the Lassos is the Polygon, which works in angles and creates a new anchor every time you click. It's fast for selecting an area that's angular with lots of straight lines, as in this example.

Feathering
Feathering a selection softens its edge, blending the transition of effects you apply to your selected area and its surroundings. There will be times when you'll want a hard edge, but usually a slight feather smoothes the transition and makes the edge less jarring to the eye. The amount of feather depends on the size of your selection and the size of the overall image. For best results, start with a small feather of a few pixels and be ready to go back in the History palette and increase or decrease the feather-trial and error pays off.

Adjusting Selections
If you make a mistake and need to adjust your selection, switch your mode. Additive mode lets you start a new selection that will be added to your current one; Subtractive mode lets you remove areas of the current selection.

With the Polygon Lasso set to additive mode and a feather of 5 pixels, I clicked at the top-left corner of the one-way sign, which created the first anchor point of my selection. I then worked my way clockwise around the signs, clicking to create a new anchor each time I wanted to start a new angle until I had completely enclosed the signs and post. As I had already set my feather in the tool properties, there was no need for the Select > Feather command.

Next I used the Select > Inverse command to change my selection from the stop sign to everything else, as it was the background that I wanted to desaturate. To finish the effect, I created a new Hue/Saturation Adjustment Layer, which was automatically masked based on my selection and reduced the saturation to -100%. That removed all color information from the background without effecting the stop sign.

Text And Photography By Rob Sheppard

Adjust Tonality And Color

Want better color? A lot of photographers go right to Hue/Saturation, but often too early. For us to see color at its best in a photograph (and to use Hue/Saturation properly), we need to also see strong blacks and whites in the image. They create a visual reference for the eye to allow us to interpret color well.

In Photoshop, use Levels to set black and white as soon as your photo is open (you can do the same with RAW files using a similar technique in Camera Raw as noted below). I recommend you use a Levels adjustment layer rather than adjusting directly into the photo's pixels because adjustment layers let you adjust and readjust with no change in image quality.

You don't need to understand all the parts of the Levels dialog box in order to use Levels to set blacks and whites. You only need to know the black and white sliders under the histogram. Here's how to use them:

1. Set blacks. Hold down the Alt/Option key as you click on the left, black slider. As you move the slider, the screen will change to a black-and-white threshold screen that shows where blacks are appearing in the image. You can move the slider until blacks just start to appear or you can be more interpretive and extend the blacks into larger areas of the photo (be aware that these areas are pure black without detail). Colors on the screen are showing the RGB channels as they max out. In Camera Raw, use Alt/Option with the Shadows slider for the same threshold screen.

2. Set whites. Hold down the Alt/Option key as you click on the right, white slider. As you move the slider, the screen will change to a black-and-white threshold screen that shows where whites are. Most of the time, you'll move the slider only until whites just start to appear. Colors on the screen are showing the RGB channels as they max out on the bright side. In Camera Raw, use Alt/Option with the Exposure slider for the same threshold screen.

3. Fix Midtones. A photo can look under- or overexposed, depending on midtones. Curves are the best way to adjust midtones, but you can use the middle gray slider of the Levels control, too (do it as a separate adjustment, however, from the blacks and whites to give you more flexibility, especially if you use adjustment layers). With Curves, just click on the center line and drag it up slightly for a brighter image, down for darker (you really don't have to move this a lot). The Tone Curve in Camera Raw is a Curves adjustment (the Brightness slider can also be used for midtones).

This simple adjustment will often give a solid boost to the colors in your photo. At the minimum, it will make the image have good contrast that will give prints some snap and life and make other color adjustments more reasonable. Keep in mind that this adjustment must fit the photograph. It won't work on foggy scenes, for example, because there should be no pure black or white in such an image.

Remove Imperfections

Photoshop provides lots of great retouching tools, including some introduced with the most recent versions, such as the handy Spot Healing Brush. But for general retouching versatility, you can't beat the trusty Rubber Stamp, a.k.a., the Clone tool.

Text And Photography By Mike Stensvold

Basically, the Rubber Stamp samples (copies) an area of an image, then pastes it over another area of the image. You select the area to be sampled and the area(s) over which to paste the sampled area. The most common use for the Rubber Stamp is to remove unwanted objects from an image, but you can also use it to add objects.

Using Rubber Stamp
The basic operation consists of two steps. While holding down the Alt/Option key, click on the area you wish to sample; this will copy that area. Then release the Alt/Option key and click on the area of the image where you want to paste the sampled area. To paste the sampled area over a larger area, you can either click repeatedly across that area, or click and drag across the area. To remove a dust spot from the sky area of a landscape image, click in the sky near the dust speck to copy the sky, then click and drag across the dust speck to paste sky over it.

Adjusting Stamp Behavior
You can adjust the diameter of the brush to match your needs. Generally, a brush size slightly larger than the size of the area you want to retouch is best. There's a brush-size slider on the Options bar above the image window, which allows you to set any brush size from 1 to 2500 pixels. You can quickly adjust brush size in 10-pixel increments by pressing the bracket keys ( [ to decrease brush diameter, ] to increase it). You can also adjust the brush's hardness or softness, a soft-edged brush generally being the better choice (a hard-edged brush is good for hard-edged areas such as the edge of a building).

The Options bar also provides controls to adjust opacity, blending mode and more. Higher opacities obscure more of the underlying area; lower opacities allow more of the underlying area to show through your cloning. There are too many blending modes to cover here, but two useful ones are Lighten and Darken. Lighten causes your cloning to affect only underlying pixels that are darker than the sampled data; Darken causes your cloning to affect only underlying pixels that are lighter.

If you check the Aligned box on the Options bar, the Clone tool will resample pixels each time you click the mouse button—handy when you're cloning a large or variable area. If you uncheck the Aligned box, the tool will continue to paste the originally sampled area each time you click and drag. If you check the Sample All Layers checkbox, the tool will copy from all visible layers; if you uncheck the box, the tool will copy from only the active layer.

It takes practice to master the Rubber Stamp, but put in the practice and you'll soon have one of Photoshop's most valuable tools at your disposal. A final tip: Don't be afraid to zoom the image up to 100% or even more to get a good view of the area you're working on. With the zoomed image on screen, press the space bar, and the cursor will change to a hand icon; click while holding down the space bar and you can move the image around in the window to access any desired portion of it.

Sharpen Details

Every image that comes out of a digital camera requires sharpening. That's because as light passes through a lens to the sensor and the data is converted from analog to digital, some "softening" occurs. Though digital cameras apply in-camera sharpening, additional global and selective sharpening is usually needed. The Unsharp Mask tool provides the greatest level of control.

Text And Photography By Ibarionex R. Perello

Configuring Unsharp Mask
There are three controls available in the Unsharp Mask dialog box: Amount, Radius and Threshold. The Amount value, which ranges from 0% to 500%, determines the intensity of the sharpening effect. The resolution of the image will largely influence your Amount setting, with higher-resolution cameras allowing for Amounts as much as 200% and sometimes even higher.

Radius affects the scope of the sharpening, with higher numbers increasing the impact. Typically, the Radius is small, from 0.3 to 2.0. You know your Radius is too big if you begin to see a halo effect around the edges of objects in your image.

Threshold controls which pixels will or won't be sharpened based on the difference in brightness between a pixel and its neighbor. If the Threshold is set for 3, this means that if two adjacent pixels have a value of 100 and 102, they will be unaffected by sharpening because the difference is less than the Threshold amount of 3. This helps prevent areas of uniform color or tones from being sharpened, such as a sky.

When And Where To Sharpen
Usually, it's best to sharpen last, after you've made your other adjustments and resized your image for the intended output. Reducing or increasing your file size after sharpening can adversely affect image quality.

Sometimes, you want to limit the effects of sharpening to a specific area. For example, when working on a portrait, I don't want everything in the image to be sharpened-the eyes, nose, mouth and hair are most important. So, while I apply a small amount of global sharpening to the image, I want the greatest amount isolated to those facial features. You can isolate the effect with a feathered selection or by applying the sharpening to a duplicate layer and erasing the effect in unwanted areas with a soft-edged eraser.

source : www.dpmag.com

Black & White Basics

noreply@blogger.com (Anonymous) — Tue, 16 Jul 2013 03:36:00 +0000

What you need to know to make the best black-and-white images

FINAL

original

Making black-and-white images is easier than ever, thanks to black-and-white adjustments in Adobe Lightroom and Photoshop, as well as black-and-white plug-ins like Nik Software's Silver Efex Pro, Perfect B&W from onOne Software and Topaz Labs' B&W Effects.

Sure, you can play around with the sliders in the programs and plug-ins, and you may wind up with a cool-looking image. With an understanding of the basics of black-and-white imaging, however, you can create a more powerful, more dramatic and even more artistic image. I'll cover those basics in this column. I'll use some of the recent photographs that I've taken in Death Valley to illustrate my points.

Before we get going, however, here's an important thing to think about when it comes to creating a great black-and-white image. As you're composing your image, you need to learn to see in tones, rather than seeing colors, and to envision how shadows and highlights will "play" in your black-and-white images. How will the scene look without color? After a while, you'll be able to visualize the final image more easily in black-and-white.

Here's the color file from which I created the black-and-white image that opens this column. It's nice enough, but I thought a black-and-white image would have more impact. Why? Because when you remove the color (or true color) from the scene, you're removing some of the reality, and when you remove some of the reality, an image can look more creative and artistic.

I created the opening image using Nik Silver Efex Pro, paying close attention to the basics of black-and-white photography: adjusting Levels, understanding the effects of filters and controlling contrast. These are the black-and-white basics you need to consider when working with software to convert an image.

Basic #1: You need the blacks to be black and the whites to be white. You can accomplish that goal by checking the Levels of your color file. If there are gaps at either end of the histogram, as there were here, simply move the triangle sliders inside both ends of the "mountain range." After you click OK, your Levels will be adjusted, and the blacks will be black and the whites will be white. Of course, this is a basic Levels guideline to follow. It worked for this image because I didn't want my shadows to be blocked up or my highlights to be overexposed.

Basic #2: Learn about color filters. Understanding the effects of color filters is very important in creating the black-and-white effect that you desire. You'll find many articles online that show you the benefits of filters like red, orange, yellow, green, blue and more. [Editor's Note: See our guide to the effects of color filters for black-and-white at tinyurl.com/black-white-filters.]

After you learn about the effects of filters, click on a filter in your black-and-white software (or adjust that color slider in Lightroom or Photoshop) to see the effect in action. You'll be surprised at how your image changes as you move from filter to filter. I used a red filter in Topaz Labs' B&W Effects to create this black-and-white image. Red is a popular filter for landscape photography, as it makes a blue sky dramatically black. Yellow is popular for people photography, as it adds a smooth look to skin tones.

Basic #3: Consider contrast. This image has strong contrast, one of the elements that contributes to strong black-and-white images. When composing an image for black-and-white, strong contrast is often desired, which is one reason to shoot in the early morning or late afternoon (as I did here) when long and strong shadows add contrast to a scene.

One method for increasing contrast is simply to use the Contrast slider. A better way is to create an "S" curve in Curves, adding and adjusting the anchor points as shown here in this screenshot of the Curves dialog in Photoshop. The point of moving the bottom-most anchor point inward is to protect the shadows. The point of moving the uppermost anchor point inward is to protect the highlights.

Well, my friends, I hope these examples inspire you to create some cool black-and-white images. Experiment and have fun, which is what photography is all about.

By Rick Sammon

source : www.dpmag.com