Everyone knows that 2 x 2 =4.
每个人都知道2 x 2 = 4。
How about: red x green = ?
怎么样：红色x绿色=？
Well, the answer actually depends on the value (lightness/darkness) of the red and green used, when you’re dealing with Multiply Mode in Photoshop.
嗯，答案实际上取决于在Photoshop中处理“ 乘以模式”时使用的红色和绿色的值(明暗度)。
Multiply Mode, according to Photoshop help:
乘模式，根据Photoshop帮助：
Looks at the color information in each channel and multiplies the base color by the blend color. The result color is always a darker color. Multiplying any color with black produces black. Multiplying any color with white leaves the color unchanged. When you’re painting with a color other than black or white, successive strokes with a painting tool produce progressively darker colors. The effect is similar to drawing on the image with multiple magic markers.
查看每个通道中的颜色信息，然后将基础颜色乘以混合颜色。 结果颜色始终是深色。 将任何颜色与黑色相乘会产生黑色。 将任何颜色与白色相乘将使颜色保持不变。 当您使用黑色或白色以外的颜色进行绘画时，使用绘画工具进行的连续笔触会逐渐产生较深的颜色。 效果类似于在带有多个魔术标记的图像上绘制。
Let’s get to some examples.
让我们来看一些例子。
When you have a grayscale layer set to Multiply, the results are pretty predictable. Black areas will remain black; white areas will be transparent and allow the base layers to show through; grey areas will have partial opacity. In this example, I’ll start with a greyscale pawprint, then set the layer to “Multiply” over another image:
当您将灰度图层设置为“乘”时，结果是可以预测的。 黑色区域将保持黑色； 白色区域将是透明的，并允许基础层显示出来； 灰色区域将具有部分不透明度。 在此示例中，我将从灰度脚印开始，然后将图层设置为在另一幅图像上“乘以”：
Now, I don’t pretend to fully understand exactly how the Multiply Mode works when it comes to blending colors — I kind of get it, but I wouldn’t be able to predict what the end result of blending two images or colors would look like to great detail. You’ll probably find as well that it’s just going to take some experimentation. Maybe this example will help:
现在，我无法假装不完全了解乘法模式在混合颜色时的工作原理，虽然有点理解，但我无法预测将两个图像或颜色混合后的最终结果喜欢细节。 您可能还会发现，这将需要进行一些实验。 也许这个例子会有所帮助：
Take the original image of the dog, plus a rainbow pawprint. Set the pawprint to Multiply mode, and here’s the result — kind of like a “clear rainbow plastic” effect, but that the result colors are slightly darker, as well:
拍摄狗的原始图像，再加上彩虹脚印。 将脚印设置为“乘以”模式，结果如下—有点像“透明的彩虹塑料”效果，但结果颜色也略深：
Okay, now for the practical applications. I have two:
好的，现在用于实际应用 。 我有两个：
1. Darken pictures.
1.使图片变暗。
This application is sometimes useful. In particular, when you have a slightly overexposed photo (think “washed out”), you can duplicate the photo on a new layer and set it to multiply, then play with the opacity level of the new layer until you feel the darker values are adequately … dark.
该应用程序有时很有用。 特别是，当您的照片稍微曝光过度(认为是“冲洗掉”)时，可以将照片复制到新图层上并将其设置为倍增，然后使用新图层的不透明度级别，直到感觉到较暗的值为止。足够……黑暗。
Here’s my original dog picture:
这是我的原始狗图片：
I’ll duplicate the layer, set it to Multiply mode, and change the opacity to 40 or 50%:
我将复制该图层，将其设置为“乘法”模式，并将不透明度更改为40或50％：
Here’s the result; while the light areas haven’t been too affected, the darker areas are definitely a little darker:
结果是这样； 虽然亮区域并没有受到太大的影响，但是较暗的区域肯定要暗一些：
(download example .psd file for dog examples)
( 下载用于狗示例的示例.psd文件 )
(Side note: I would probably play with the Saturation, Levels, or Curves to put more “oomph” into the final image.)
(旁注：我可能会使用“饱和度”，“色阶”或“曲线”来为最终图像添加更多的“变幅”。)
On to the next practical application…
继续下一个实际应用…
2. Color line drawings.
2.彩色线条图。
This is probably one of my most-used blending mode applications. Because Multiply Mode works where black areas are black, and white areas transparent, it is ideal for “coloring” black and white line drawings.
这可能是我最常用的混合模式应用程序之一。 由于乘法模式适用于黑色区域为黑色而白色区域透明的情况，因此非常适用于“着色”黑白线条图。
I’ll start with a scanned line drawing:
我将从扫描线图开始：
I’ll set that layer to Multiply Mode, then add another layer underneath. As I paint (in color) on the bottom layer, the colors show through!
我将该层设置为“乘法模式”，然后在下面添加另一层。 当我在底层绘画(用彩色)时，颜色会透出！
The beauty of this method is that you don’t have to worry about losing detail on the line drawing, as you don’t touch that layer at all. (Contrast this with using the paint bucket or paintbrush tools, where inevitably some of the pixels will be lost from the line drawing.) As you can see from this snapshot of the bottom layer, I wasn’t overly careful with the color edges:
这种方法的优点在于，您不必担心会丢失线图上的细节，因为您根本不需要触摸该层。 (与使用油漆桶或画笔工具进行对比，不可避免地，某些像素会从线条图中丢失。)正如您从底层快照中看到的那样，我对颜色边缘不是很谨慎：
Here’s my final image, in color:
这是我最终的彩色图片：
(download example. psd file)
( 下载示例.psd文件 )
Now, I bet you can think of more ways to use Multiply Mode to your advantage. For example, the line art technique would work just as well with “colorizing” black and white photos. Feel free to share other neat ways of using Multiply Mode by adding a comment!
现在，我敢打赌，您可以想出更多的方式来使用乘模式以发挥自己的优势。 例如，线条艺术技术对于“彩色化”黑白照片同样适用。 通过添加评论，随时分享使用乘法模式的其他巧妙方式！
翻译自: https://www.sitepoint.com/multiply-mode-in-photoshop/
