倾斜摄影的处理流程：_摄影：什么是色差，如何解决？
倾斜摄影的处理流程：
You may have heard photographers talk about “Chromatic Aberration” like it’s a disease. Today, we’ll give a explanation of what this term means, and share an advanced technique for removing it from photos, should the need arise.
您可能听说过摄影师说“色差”是一种疾病。 今天，我们将解释这个术语的含义，并分享在需要时将其从照片中删除的先进技术。
A function of light conditions or using a lens incorrectly, chromatic aberration can ruin a photograph and reduce the amount of detail captured by the camera. While lenses and cameras are developed with technology to reduce these glitches, the simple fact of the matter is they still pop up under the right (or wrong?) conditions. Keep reading to learn more, including how you can fix them with Photoshop or GIMP.
由于光线条件的影响或使用镜头的不正确，色差会破坏照片并减少相机捕获的细节量。 虽然镜头和相机采用减少这些毛刺的技术进行了开发，但问题的简单事实是它们仍然会在正确(或错误的)条件下弹出。 继续阅读以了解更多信息，包括如何使用Photoshop或GIMP对其进行修复。
在摄影中定义色差 (Defining Chromatic Aberration in Photography)
Here’s the image we found that’s a good example of chromatic aberration. Parts of the image appear soft, which could be partly from the lens being slightly out of focus, except that the aberration is almost certainly causing a loss of detail resolution. Notice the blue halo on the left hand side of the image and scattered throughout in various areas.
这是我们发现的图像，它是色差的一个很好的例子。 图像的某些部分看起来很柔和，这可能部分是由于镜头稍微失焦造成的，除了像差几乎可以肯定会导致细节分辨率下降之外。 请注意，图像左侧的蓝色光环散布在各个区域。
Lenses can change the speed light moves through it, and this is a function the frequency of that light. As the light travels through this lens, the different wavelengths (colors) move at different speeds and fall in different places on the sensor. Sometimes using a lens in a way it was not designed can cause an aberration—like this shot, using a lens that was possibly inappropriate such a extreme closeup. As a result, the red, green, and blue converge on different points and create image channels that don’t line up.
镜头可以改变光线穿过的速度，这是光线频率的函数。 当光线穿过此镜头时，不同的波长(颜色)以不同的速度移动并落在传感器的不同位置。 有时以非设计方式使用镜头可能会导致像差，例如这张镜头，使用可能不合适的镜头(例如极端特写)。 结果，红色，绿色和蓝色会聚在不同的点上，并创建不对齐的图像通道。
There are more technical descriptions of what a chromatic aberration is, but for our purposes, we’ll be focusing on this simpler explanation and how it relates to image files.
关于色差有更多的技术描述，但是出于我们的目的，我们将集中于这个更简单的解释以及它与图像文件的关系。
In this animation, it becomes more clear what all this means. You can see the image shift as it cycles through the red green and blue color channels. Each channel may be rendered reasonably sharply, but because they combine to create an image, the image quality is damaged. It is possible to repair that damage, and here’s a proper method, using an understanding of what a chromatic aberration is.
在此动画中，所有这些意味着什么变得更加清楚。 您可以看到图像在通过红色，绿色和蓝色通道循环时发生移位。 可以合理清晰地渲染每个通道，但是由于它们组合在一起会生成图像，因此图像质量会受到损害。 可以通过了解色差是什么来修复这种损坏，这是一种正确的方法。
修正色差的高级方法 (Fixing A Chromatic Aberration the Advanced Way)
Open the image afflicted with aberration. The appropriate way to fix an aberration is to simply adjust and align the channels to fit to one another. This can be a challenge, as light tends to speed up at different points in the lens, creating more distortion is some areas than others.
打开出现像差的图像。 修正像差的适当方法是简单地调整并对齐通道以使其彼此适配。 这可能是一个挑战，因为光线倾向于在镜头中的不同点加速，因此某些区域比其他区域产生更多的失真。
A note to readers: Our demonstration is done in Photoshop. But for those readers using other programs, like freeware GIMP, can also use this method, as we’ll be using techniques common to powerful image editing software. Readers working from RAW photographs have a quicker, more automatic method for reducing aberrations already existing inside camera raw. There’s also a specific kind of aberration sometimes called “purple fringe” that isn’t what we’re adjusting today. More information on all of that later.
敬告读者：我们的演示在Photoshop中完成。 但是对于那些使用其他程序(例如免费软件GIMP)的读者，也可以使用这种方法，因为我们将使用功能强大的图像编辑软件所共有的技术。 读取RAW照片的读者可以使用一种更快，更自动的方法来减少相机原始照片中已经存在的像差。 还有一种特殊的像差有时被称为“ 紫色条纹 ”，这不是我们今天要调整的。 稍后将提供所有更多信息。
Begin your work by making a copy of your image. We’ll be doing the majority of our adjustments on this copy, but we’ll also need our background image when we’re done.
通过复制图像开始您的工作。 我们将对此副本进行大部分调整，但是完成后还需要背景图片。
We’ll start by adjusting our green channel to fit our red channel. The frequency of the light speeds up as light moves from red to green to blue, so we’ll adjust green and blue to fit to slower frequency red. Select your green channel and make sure that your blue channel is turned off so you can see how your green and red channels overlap.
我们将从调整绿色通道以适合红色通道开始。 随着光从红色变为绿色再变为蓝色，光的频率会加快，因此我们将调整绿色和蓝色以适应频率较低的红色。 选择绿色通道，并确保关闭蓝色通道，以便您可以看到绿色和红色通道如何重叠。
With your green channel selected, press Ctrl + A to select all, then press Ctrl + T to do a free transform on that green channel.
选中绿色通道后，按Ctrl + A选择全部，然后按Ctrl + T对该绿色通道进行自由变换。
Carefully transform the channel to fit around the outside edges. When you’re done, press enter, then Ctrl + D to get rid of the marquee. Don’t worry if part of your image still appear have some aberration. We will fix these later.
小心地将通道变形以适合外部边缘。 完成后，按Enter键，然后按Ctrl + D摆脱字幕。 如果图像的一部分仍然出现畸变，请不要担心。 我们稍后会修复。
Same adjustment goes for the blue. Turn off the green channel, then select and turn on the blue channel as shown.
同样的调整也适用于蓝色。 关闭绿色通道，然后选择并打开蓝色通道，如图所示。
You’ll make a similar adjustment to your blue channel—select all with Ctrl + A, then transform the channel with Ctrl + T. When you’re done and your image fits around the outside edges, press enter to commit to the transformation.
您将对蓝色通道进行类似的调整-使用Ctrl + A选择所有通道，然后使用Ctrl + T转换通道。完成后，图像适合外部边缘，按Enter确认转换。
When you return to the combined RGB channels, you’ll find that this has repaired much of the obvious aberration in the photo. It’s probably impossible to perfectly repair aberration on every photo, so it’s not a perfect repair. Parts of the image are now somewhat blurry, so let’s take a moment to repair those.
返回组合的RGB通道时，您会发现这已修复了照片中的许多明显像差。 完美修复每张照片上的像差可能是不可能的，因此这不是完美的修复方法。 现在图像的某些部分有些模糊，因此让我们花点时间修复它们。
修复因通道移位而引起的模糊 (Repairing Blurs Caused by Shifting Channels)
You can easily spend an unnecessary amount of time tweaking out aberrations, but for the sake of demonstration, we’ll just eliminate the ones causing blur in the main focal point.
您可以轻松地花费不必要的时间来调整像差，但是为了演示起见，我们将消除那些导致主焦点模糊的像差。
Create a copy of your newly tweaked layer.
创建新调整的图层的副本。
Select the green channel and nudge it to fit in your focal point areas. You’ll have to select all with Ctrl + A before you can nudge the image in the green channel. Repeat with the blue channel, worrying only about your focal points.
选择绿色通道并将其微调以适合您的焦点区域。 您必须先按Ctrl + A选择全部，然后才能在绿色通道中微调图像。 重复蓝色通道， 只担心您的焦点。
Mask out the areas outside of your focal point. Use your brush tool to blend them together. When you’re done, group your two copies and create a layer mask for your group. Use it to revert any areas you care to to your original image.
遮盖住焦点以外的区域。 使用画笔工具将它们混合在一起。 完成后，将两个副本分组，并为您的组创建一个图层蒙版。 使用它可以将您关心的所有区域恢复为原始图像。
Create a small crop to remove the edges affected by the channels you’ve transformed.
创建一个小的裁切，以删除受转换通道影响的边缘。
Repeat this process as many times as you feel you need to to perfectly fix aberrations to the level you need. It may take multiple adjustments to channels to get the image perfect, or you may be satisfied with one simple adjustment.
您可以根据需要多次重复此过程，以将像差完美地校正到所需的水平。 可能需要对通道进行多次调整才能获得完美的图像，或者您可能对一种简单的调整感到满意。
Feeling a little bit more confident about how to deal with this sort of problem? Confused about the complexity of this how to? Have a better, simpler method for combatting chromatic aberration? Tell us about it in the comments, or send your suggestions to [email protected]
对如何处理此类问题更有信心？ 对此感到困惑的如何？ 有更好，更简单的方法来消除色差吗？ 在评论中告诉我们，或将您的建议发送至[email protected] 。
Image Credits: Daisy by Ivan T, Creative Commons.
图片来源：Creative Commons的Ivan T的雏菊。
翻译自: https://www.howtogeek.com/108321/what-is-a-chromatic-aberration-and-how-can-i-fix-it/
倾斜摄影的处理流程：