亮度和对比度

In this lesson, you'll reuse the image, "05_PalmTrees1.jpg." If you don't have it saved in its unedited version from the previous lesson, you can download it again as "05_PalmTrees1a.jpg." You'll also use the image, "06_PalmTrees2.jpg." Before continuing, click on the Resources tab and download these images.
::在此课中, 您会重新使用图像, “ 05_ PalmTreees1. jpg ” 。 如果您没有在未经编辑的版本中保存上一个课, 您可以再次下载它为“ 05_ PalmTreees1a. jpg ” 。 您还将使用图像“ 06_ PalmTreees2. jpg ” 。 在继续之前, 请点击资源标签并下载这些图像 。

Like Exposure , if an image is underexposed or overexposed, you can adjust it using Brightness & Contrast . However, unlike Exposure , Brightness & Contrast tends to keep the highlights (brights) unchanged while adjusting the midtones and shadows (darks). It also provides an additional slider for adjusting contrast – the amount of difference between the shadows and highlights.
::像曝光一样,如果图像暴露不足或过度,你可以使用亮度和对比度来调整图像。 但是,与曝光不同,亮度和对比度往往保持亮度(brights)不变,同时调整中点和阴影(darks ) 。 它还为调整对比度(阴影和亮度之间的差异)提供了额外的滑动器。

Open the image “05_PalmTrees1.jpg” again in Pixlr Editor. As you may recall, this image is underexposed. This time, you’ll use Brightness & Contrast to fix the image.
::在 Pixlr 编辑器中再次打开图像“ 05_ PalmTreees1. jpg ” 。 您可能记得, 此图像曝光不足。 这次您将使用 Brightness 和 Contrast 来修正图像 。

Click on the Adjustment menu and choose Brightness & Contrast .
::点击调整菜单并选择亮度和对比度 。

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1. Click and drag the Brightness slider to the right to make the image lighter.
   ::单击并拖动“亮度”滑块到右边使图像更轻。
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2. This will wash out the image. Wash out describes the appearance when an image with little difference between the darks and highlights. This difference is called contrast .
   ::这将冲洗图像。 洗掉描述图像的外观, 当图像在黑暗和亮点之间几乎没有区别时。 这个差异被称为对比 。
播放段落
3. Drag the Contrast  slider to the right to increase the contrast.
   ::将对比度滑动器拖到右侧以增加对比度。
播放段落
4. When you have the brightness and contrast adjusted, click the OK button.
   ::当您调整了亮度和对比度时,请单击“确定”按钮。

Now, the image is more balanced – not too dark, with enough contrast to give it depth.
::现在,图像更加平衡 — — 不是太暗, 有足够的对比度来给它带来深度。

Save and share the Brightness & Contrast -adjusted image with your teacher, and be prepared to discuss how it shows what you’ve learned.
::并准备讨论它如何显示你学到的东西。

Now, find the image “06_PalmTrees2.jpg” and open it in Pixlr Editor. The image is a little overexposed - too bright. Note that any areas in a photo that are completely overexposed can’t be darkened. These areas are referred to as blown out . One of these areas is the beach sandbar in the middle right area of the image. The sand is very bright, there is no detail available in the pixels, and darkening can't create something that isn't there.
::现在, 找到“ 06_ PalmTreees2. jpg” 图像, 并在 Pixlr 编辑器中打开它。 图像有点太暴露了 - 太亮了。 请注意, 照片中任何被完全过度曝光的区域都不会被暗淡。 这些区域被称为被吹灭。 其中之一是图像右侧区域的沙滩沙滩。 沙子非常亮, 象素中没有细节, 更暗无法创造不存在的东西 。

Again, click on the Adjustment menu and choose Brightness & Contrast .
::再次单击调整菜单并选择亮度和对比度。

播放段落
1. Since the image is too bright, click and drag the Brightness slider to the left to darken it.   This will wash out the image.
   ::由于图像太亮, 请单击并拖动“ 亮度” 滑块到左边, 使其变暗 。 这将冲刷图像 。
播放段落
2. Drag the Contrast  slider to the right to add contrast. You can also click into the number fields and change the numbers – negative for darker/less contrast and positive for lighter/more contrast.
   ::将对比度滑块拖到右侧添加对比度。您也可以单击数字字段并更改数字-暗/无对比度为负数,较轻/更对比度为正数。
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3. When you have the brightness and contrast adjusted, click the OK button.
   ::当您调整了亮度和对比度时,请单击“确定”按钮。

Save and share this Brightness & Contrast -adjusted image with your teacher, and be prepared to discuss how it shows what you’ve learned.
::并准备讨论它如何显示你学到的东西。

RECORD YOUR FINDINGS
::记录你的调查结果

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• What does it mean when an area of an image is blown out?
  ::当一个图像区域被炸毁时,这意味着什么?
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• Describe what an image looks like when it is washed out.
  ::描述图像被冲走时的外观。
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• How is Brightness & Contrast different from Exposure ?
  ::亮度和对比度与曝光有何不同?