After the last hard topics, Difference Mode is refreshingly easy in Photoshop to understand:
在最后一个困难的话题之后，差异模式在Photoshop中令人耳目一新，易于理解：
Difference Mode: Looks at the color information in each channel and subtracts either the blend color from the base color or the base color from the blend color, depending on which has the greater brightness value. Blending with white inverts the base color values; blending with black produces no change.
差异模式：查看每个通道中的颜色信息，然后从基色中减去混合色或从混合色中减去基色，这取决于哪个亮度值更大。 与白色混合会反转基本色值； 与黑色混合不会产生任何变化。
It’s easy for me to think about this when I consider RBG values. When you express a color in red-green-blue values, each color can have a value from 0 to 255. If you have red=0, green=0, and blue=0 (0-0-0), you end up with black. If you have 255-255-255 (red, green, and blue turned up all the way), you end up with white.
在考虑RBG值时，我很容易想到这一点。 当您用红色-绿色-蓝色值表示颜色时，每种颜色的值都可以在0到255之间。如果您有red = 0，green = 0和blue = 0(0-0-0)，则最终黑色。 如果您的像素为255-255-255(红色，绿色和蓝色一直都出现)，则最终会显示白色。
So let’s take a blue square with RGB value of 27-97-168 (you can tell from the numbers that it will be mostly blue, because red and green values are much lower) and put it on top of a white background. Let’s duplicate the blue square on another layer and set that one to Difference Mode and move it over. The white (255-255-255) will subtract the blue (27-97-168) and you’ll end up with an orange-ish color (228, 158, 87). Cool, huh?
因此，让我们以RGB值为27-97-168的蓝色正方形(您可以从数字中看出，由于红色和绿色的值要低得多，它将大部分为蓝色)并将其放在白色背景上。 让我们在另一层上复制蓝色正方形，然后将其设置为“差异模式”并将其移到上方。 白色(255-255-255)将减去蓝色(27-97-168)，最终会变成橙色(228、158、87)。 酷吧？
If you passed first grade math, like me, you’ve probably figured out by now that if you duplicate a layer and keep the two layers centered together, then set the top one to Difference Mode, you’ll end up with a black area. Since the layers are identical, the colors subtract to 0-0-0, resulting in black.
如果您像我一样通过了一年级数学，那么您现在可能已经知道，如果复制一个图层并将两个图层居中放置，然后将最上一层设置为“差异模式”，您将得到一个黑色区域。 由于图层相同，因此颜色相减为0-0-0，从而导致黑色。
A cool effect that you can achieve with Difference Mode is a black neon glow outline type effect.
使用“差异模式”可以实现的很酷的效果是黑色霓虹灯轮廓轮廓效果。
1. Take a picture, any picture. (I’ll use the standard yellow rose picture that I’ve got.)
1.拍摄一张照片，任何图片。 (我将使用获得的标准黄玫瑰图片。)
2. Duplicate the layer.
2.复制图层。
3. Set the top layer to Difference Mode. You’ll just see black at this point.
3.将顶层设置为差异模式。 此时您会看到黑色。
4. Go to Filter > Blur > Gaussian Blur (you can experiment with the other ones later, for fun) and play around with the radius. I set mine to 8 pixels, but it just depends on your picture.
4.转到“滤镜”>“模糊”>“高斯模糊”(您以后可以尝试使用其他模糊算法，以获取乐趣)并使用半径。 我将我的像素设置为8像素，但这仅取决于您的图片。
5. The picture will start to form a faint neon effect. You should be able to see this from the preview. Find a setting that suits you and apply the blur effect.
5.图片将开始形成微弱的霓虹灯效果。 您应该能够从预览中看到它。 找到适合您的设置并应用模糊效果。
Another neat application of this is the overlapping “cutout” effect, which can be used for a quick web graphic or logo.
另一个很好的应用是重叠的“抠图”效果，该效果可用于快速Web图形或徽标。
1. Create two layers with shapes or text on them. This works best with solid shapes. The bottom layer should be black, the top layer should be white, and they should both be on a white background.
1.创建两层带有形状或文本的图层。 这对实体形状最有效。 底层应为黑色，顶层应为白色，并且两者都应位于白色背景上。
2. Set the top, white layer to Difference Mode, and you’ll immediately get an overlapping cutout effect!
2.将顶部白色图层设置为“差异模式”，您将立即获得重叠的抠图效果！
Finally, one application that I hadn’t considered before is using Difference Mode to help you “stitch” two pictures together – like if you’re making a panorama, or if you’ve scanned a larger document by scanning smaller pieces of it. This web site describes it, but I’ll go over it briefly.
最后，我以前没有考虑过的一个应用程序是使用“差异模式”来帮助您将两张图片“拼接”在一起，例如制作全景图或通过扫描较小的文档来扫描较大的文档。 该网站对此进行了介绍 ，但我将对其进行简要介绍。
1. Let’s say that you have a large photo and a small scanner. You scan one side of the large photo, then the other side, with a small overlap in between.
1.假设您有一张大照片和一台小型扫描仪。 您先扫描大照片的一面，然后再扫描另一面，两面之间有很小的重叠。
2. In Photoshop, you make a new document big enough for the whole photo and drop in the two halves on their own layers. Recall that there is some overlap; you try to line them up painstakingly.
2.在Photoshop中，您要为整个照片制作一个足够大的新文档，并将其分成两半放在自己的图层上。 回想一下，有一些重叠。 您会尽力将它们排列起来。
3. Setting the top layer to Difference Mode can help you line up the pictures more easily. Remember that if the overlap part is lined up perfectly, then the colors will subtract from each other, leaving a black stripe. So nudge the layer with the move tool or arrow key until you get as much of a black stripe as you can get with your scan. Turn the top layer back to Normal Mode and see how it looks!
3.将顶层设置为差异模式可以帮助您更轻松地排列图片。 请记住，如果重叠部分排列整齐，则颜色将彼此相减，留下黑色条纹。 因此，使用移动工具或箭头键微调图层，直到获得尽可能多的黑色条纹为止。 将顶层返回普通模式，看看它的外观！
翻译自: https://www.sitepoint.com/making-a-difference/
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