ဓါတ္ပုံျပင္နည္း Noise reduction

Noise reduction

Some images may have a lot of noise, which causes them to look grainy. You can compensate for this by reducing the image noise, as in the example below:

Understanding noise reduction

When you apply noise reduction, you're actually removing information from the image. As a result, you'll need to use this feature carefully—removing too much noise can result in blurriness and a loss of detail. The goal of noise reduction is not to completely remove all noise from the image; instead, you're just trying to make the image look cleaner and clearer.
As with sharpening, you should always look critically at the image to see if you're getting the results you want. Losing a small amount of detail may be unavoidable when reducing noise, so you'll need to make careful adjustments to find the right balance. It's often better to remove less noise in order to preserve as much detail as possible.
When you use this tool, you'll be able to control many different settings, including:

• Strength: This setting controls the overall level of noise reduction that will be applied. We recommend starting with this setting at the maximum value (10) because it will make it easier to see the effect the other settings have. After you've adjusted the other settings, you can decrease the strength as needed to get the desired amount of noise reduction.
• Preserve Details: This determines how many details from the original image will be preserved. If you use a value that's too low, the image will lose a lot of detail. However, anything too high will cancel out the effects of noise reduction. You'll want to experiment with this setting until you're satisfied with the result.
• Reduce Color Noise: Sometimes noise will look like small patches of individual colors, which is known as color noise. Increasing the Reduce Color Noise setting will help to reduce this. However, taking this setting too high can cause the different colors in your image to bleed together, so we recommend using a relatively low value for most images.
• Sharpen Details: Reducing image noise also causes the image to lose some sharpness. This setting allows you to add sharpness back to the details of the image. However, just like with Preserve Details, this can cancel out the effects of noise reduction, so be careful not to set it too high.

Drag the slider in the interactive below to adjust the level of noise reduction. Remember, removing too much noise will cause the image to lose detail. Try to find a level that makes the image look clean without losing too much detail.

To apply noise reduction:

1. Right-click the desired layer, then select Duplicate Layer. You'll apply the noise reduction to this duplicate layer, which will prevent you from accidentally altering the original.
2. A dialog box will appear. Type a name for the duplicate layer, then click OK. In this example, we'll call it Noise Reduction.
3. With the new duplicate layer selected, go to FilterNoiseReduce Noise.
   
4. A dialog box will appear. Take some time to adjust each setting, following the guidelines above—you can look at the preview window to the left of the sliders to see the effect.
   
5. Click the preview window to toggle the preview off and on. This is an easy way to compare the noise reduction with the original. To view a different part of the image, you can click and drag within the preview window. Note that you'll also see the preview in the main document window.
6. Continue to adjust the settings until you're satisfied with the results, then click OK. The noise reduction will be applied.

Open the globe_building_fullsize.jpg example file, duplicate the background layer, and apply noise reduction. Adjust the settings to find a balance between noise reduction and a loss of detail.

ဓါတ္ပုံျပင္နည္း Sharpening tips-2

Sharpening tips

Here are a few tips for getting the best results with sharpening:

• If you increase the amount of sharpening that is added, there will usually be a point where the edges in the image will start to glow, causing them to look exaggerated. Whenever you see this happen, try decreasing the amount to make the sharpening look more natural.
• If the sharpening still looks a bit unnatural, you could try reducing the opacity of the sharpened layer to make the effect more subtle.
• Note that sharpening cannot fix an image that's very blurry or out of focus—it works best with images that are clear but have a slightly soft look.
• While unsharp mask is a useful tool, Photoshop also includes other sharpening filters, which can be found in the FilterSharpen menu. Some filters, such as Sharpen and Sharpen More, apply a preset amount of sharpening. Others, such as Smart Sharpen, give you even more ways to tweak the adjustments (although this also means it's even trickier to use than unsharp mask).

If you want to learn more about using Smart Sharpen, check out the Sharpen Your Photos with Smart Sharpen video on the Adobe website.

ဓါတ္ပုံျပင္ျခင္း Sharpening

Sharpening

Sometimes an image may not be as clear as you'd like it to be. Sharpening can help to make your images look crisp and clear by enhancing the edges of objects in the image. However, adding too much sharpness can actually make an image look worse, or it can lead to a loss in image detail. Take a look at the example below:

As you can see, the right amount of sharpness makes the photo look crisp—for example, in the center image, it's easy to see the edges of the bird's feathers. But adding too much sharpness can cause the edges to look exaggerated and unnatural (these are known as halos), as in the image on the right. You may have also noticed that the background in the oversharpened image has a lot of added image noise, or graininess. We'll talk more about reducing image noise on the next page.
Whenever you apply sharpening, you'll need to look critically at the image to see if you're getting the results you want. You'll often need to make careful adjustments to get the right amount of sharpening without introducing other problems like halos or noise.

Drag the slider in the interactive below to adjust the sharpness of the image. Try to make the image look crisp but not oversharpened.

Unsharp mask

The unsharp mask filter is a common way to sharpen images in Photoshop. When you use this tool, you'll be able to control a few different settings, including:

• Amount: The amount determines how much sharpness will be applied. The amount you'll need depends on several factors, including the overall image size, so it's good to experiment with this setting.
• Radius: The radius controls the size of the details that will be sharpened, so it's generally best to use a very low value for this setting. We recommend a radius between 0.3 and 0.5 for most images, although you may find it useful to use a slightly larger radius (between 1 and 1.5) for higher-resolution images.
• Threshold: Sharpening tends to make image noise more visible. Increasing the threshold can help to reduce this by telling unsharp mask to ignore certain parts of the image. However, this can also mean that different parts of the image are not sharpened consistently. This is why we recommend keeping this setting at 0 most of the time, unless the sharpening is creating a lot extra noise.

To apply an unsharp mask:

1. Right-click the layer you wish to sharpen, then select Duplicate Layer. You'll apply the sharpening to this duplicate layer, which will prevent you from accidentally altering the original.
   
2. A dialog box will appear. Type a name for the new layer, then click OK. In this example, we'll call it Sharpened.
   
3. With the new duplicate layer selected, go to FilterSharpenUnsharp Mask. If you're using Photoshop Elements, you'll need to go to EnhanceUnsharp Mask.
   
4. A dialog box will appear. Set the desired radius size, then choose the amount of sharpness to add. We recommend experimenting with different amounts of sharpening to see what looks best. You can look at the preview window above the sliders to see how sharpening is affecting the image.
   
   
5. Click the preview window to toggle the preview off and on. This is an easy way to compare the sharpened version with the original. To view a different part of the image, you can click and drag within the preview window. Note that you'll also see the preview in the main document window.
   
6. Continue to adjust the settings until you're satisfied with result, then click OK. The unsharp mask will be applied.

Open the hawk_fullsize.jpg example file, duplicate the background layer, and apply an unsharp mask. Adjust the settings to find a balance between sharpness and a loss of detail.

If you want to learn even more about sharpening, check out this tutorial from Cambridge in Colour.

ဓါတ္ပုံျပင္ျခင္း Sharpening and Noise Reduction

Introduction

Video: Sharpening and Noise Reduction

Photoshop includes several tools you can use to correct your images. In this lesson, we'll show you how to make the following corrections:

• Sharpening: If an image is less clear than you'd like it to be, you can sharpen it.
• Noise reduction: If an image has a lot of noise, or graininess, you can reduce the image noise.

We'll also talk about the importance of using these tools correctly. If they are misused, sharpening and noise reduction can actually cause problems with your images. However, if they are used with care, they are a great way to add polish to your images.

If you'd like to follow along, you can download some or all of our example images. Just click any of the images below to open a full-sized version. Then right-click the full-sized version and select Save Image As to save it to your computer.

ဓါတ္ပုံျပင္ျခင္း Auto-adjustment tools

Auto-adjustment tools

Some images may require more specialized corrections, which can be difficult to make if you don't have a lot of experience with Photoshop. Fortunately, there are several automatic adjustment tools you can use to improve your images. In the original image below, the snow has a blueish tint; after using the Auto Color command, the snow looks white:

You'll find a few auto-correction tools, including Auto Color, in the Image menu.

Many adjustment layers also have their own automatic adjustment option. To use this tool, create an adjustment layer, then click the Auto button in the Properties panel (if available).

Most of the time, these tools will improve the overall look of an image. However, you can always manually adjust an image afterward to get the image to look exactly the way you want. If the auto-correction goes too far, you could also try reducing the opacity of the adjustment layer to 50% to make the effect more subtle.

Open the dog_fullsize.jpg example file, add a Levels adjustment layer, and use the Auto Color command in the Image menu.

ဓါတ္ပုံျပင္ျခင္း Color Corrections

Color corrections

There will be times when you may want to adjust the colors in an image. For example, you may want to modify the color intensity or even change colors for artistic effect.

Saturation

If the colors in your image are dull or muted, you can increase the saturation to make them look more vivid. You can see an example of this in the images below:

On the other hand, you can reduce the saturation to make the colors less vivid. If you remove the saturation completely, it will produce a black-and-white, or grayscale, image. You can see an example of this in the images below:

To adjust saturation, add a Hue/Saturation adjustment layer. Then click and drag the Saturation slider in the Properties panel to increase or decrease the saturation.

Drag the slider in the interactive below to adjust the saturation of the image. Careful, though! Too much saturation will cause the image to lose detail.

Saturation adjustment tips

Here are a few recommendations for getting the best results with saturation adjustments:

• Be careful not to increase the saturation too much. This can cause the colors to look unnatural, as in the example below:
  
  
• Increasing the saturation may also create image noise. We'll talk more about removing noise in the next lesson.
• For some types of pictures, especially portraits, increasing the saturation can look unflattering. In these cases, you may want to decrease the saturation.
• The Hue slider changes all of the colors in the image at the same time. This will often result in an unnatural color combination, so we don't recommend adjusting the hue unless you want an unusual effect.
  
• Although you could use the Lightness slider to increase or decrease the image brightness, you'll probably want to add a Levels or Curves adjustment layer instead—these will give you more control over image brightness.

Vibrance

Increasing the saturation can sometimes look a bit unnatural. One solution is to use a Vibrance adjustment layer instead of Hue/Saturation. Vibrance lets you boost the saturation for the parts of the image that are less colorful without oversaturating the parts that are already colorful.

Open pink_fullsize.jpg, then add a Hue/Saturation adjustment layer. Take the saturation to the highest and lowest settings to see the effect. Try to find the setting that looks best for the image.

Converting to black and white

As we mentioned above, setting the saturation to -100 will create a black-and-white image. However, this method doesn't give you much control over how the black-and-white version will look. For better results, you can create a Black and White adjustment layer.
Because black-and-white photos don't have colors, the tones (the different shades of gray) are especially important. A Black and White adjustment layer allows you to control how the different colors are mixed to create specific tones, which can make a significant difference in how the final image looks.
We recommend trying different options from the Preset menu until you find one that works well for the image—you can then make small adjustments to the individual colors as needed.

ဓါတ္ပုံျပင္ျခင္း Curves

Curves

The Curves tool is similar to levels, but it gives you more power to control shadows, highlights, and midtones separately. Because it's a more advanced tool, you'll need to be careful when using it to adjust your images.
In the example below, you can see an image before adjusting curves. To the right, you can see the curve as it appears by default. Notice how the diagonal line is perfectly straight. When you make adjustments with curves, you're creating different curves with this line.

Increasing contrast

One of the simplest adjustment you can make with curves is to increase the contrast. To do this, you would drag the curve down in the shadows on the left to make them darker, and up in the highlights on the right to make them brighter:

Decreasing contrast

In this particular image, it might be better to decrease the contrast. To do this, you would drag the curve up in the shadows on the left to make them brighter, and down in the highlights on the right to make them darker. In the image below, you can see that this makes it easier to see details on the seagull's face:

Other adjustments

You could also increase the shadows without changing the highlights. To do this, you would drag up the curve in the shadows on the left. Notice how we used multiple points to gently bring the curve back to the default position; this helps to prevent the curve from affecting the highlights or midtones. This allows us to make the seagull brighter without darkening or lightening the clouds:

You'll want to avoid using big, steep curves—anytime the curve moves too far away from the diagonal line, it will usually create problems in the image. In the example below, notice how the curve dramatically changes direction near the middle. This causes a significant loss of detail in the midtones, giving the seagull a flat, unnatural look:

To adjust curves:

1. Add a Curves adjustment layer.
   
2. Click anywhere on the line in the Properties panel to create a new point, then click and drag the point to adjust the curve. Note: Be careful not to move the two points in the lower-left and upper-right corners. It is possible to adjust these, but we recommend keeping them in the corners until you gain more experience with curves.
   
   
3. Continue to adjust the points until you're satisfied with the result. You can also press the Delete key or click and drag a point off the line to remove it.

If you're new to curves, you may want to select one of the Preset options and then make small adjustments to the curve as needed. If you need to start over, you can select Default from the Presets menu.

Using Curves in Photoshop Elements

If you're using Photoshop Elements, you won't be able to create a Curves adjustment layer, but there is a similar tool you can use. To access this tool, select EnhanceAdjust ColorAdjust Color Curves. You can then click and drag the sliders to adjust the curve.

Open the seagull_fullsize.jpg example file and add a Curves adjustment layer. Try using some of the different options from the Presets menu, then move points on the curve to see the effect.

ဓါတ္ပုံျပင္ျခင္း Levels adjustmest tips

Levels adjustment tips

Here are a few tips for getting the best results with levels:

• If you're using multiple adjustment layers, you may need to readjust the levels after making changes to other adjustment layers.
• If you want to compare the levels adjustment with the original image, you can turn the adjustment layer off and on.
• Generally, you'll want to adjust the black and white sliders so they fit the data in the histogram. For example, in the image below, we adjusted the white slider so it aligns with the right edge of the data:
  
  
  
  
   
  If you move the white slider too far to the left, you will begin to lose detail in your image. This is known as clipping. In the image below, you can see that the clouds have lost a lot of detail, and the color of the sky has also changed. Both of these problems are caused by clipping:
  
  
  
  
   
  If you move the black slider too far to the right, you will begin to see clipping in the image's shadows. In this example, the bird and branches have lost almost all of their detail. The color of the sky has also changed to a darker blue:
  
  
  
  
   
  Remember, because you're using adjustment layers none of these changes are permanent until you export your image. So if you see any clipping in your image, don't panic! Simply look at your adjustment layers to find the source of the clipping, then readjust the levels as needed.

Note that the histogram will be unique for every image. If an image has the proper exposure, the histogram will be complete, with no data missing—moving the black and white sliders in this situation would cause clipping. Instead, you can use the middle (gray) slider to increase or decrease the overall brightness.