(译自Tony Kuyper Luminosity Masks)
译者:陈晟尧
前言:
现在的国内的摄影爱好者以及部分“资深”摄影师(当然基本都是老头)都对PS后期处理照片持极端的看法。有人过度追求PS的创造效果,本末倒置,其代表为HDR的泛滥使用。诚然,HDR能够解决图片的动态范围问题,但过于虚假的表现力和夸张的色彩依然使其偏离摄影本质,跟何况HDR如今已经成为了后期快餐,“只要HDR就是好图”的概念成为了定式。还有人对于PS后期嗤之以鼻,他们都是保守派,有可能都是玩胶片出身。他们的观点是:摄影是纯粹的,任何后期手段都是画蛇添足,很假。但他们殊不知胶片时代的暗房技术也在左右着图片的好坏。
因此,任何一种极端的观点都是片面的。后期,或者更具象地说:PS,是还原现场体验的重要手段,是弥补相机成像缺陷的重要手段,可以说,好的PS是在弥补照片的缺陷,不会使图像看起来很假,也不是给照片做加法。在我看来,数码时代,一张好的照片,前期占6分,后期占4分。前期再好,也只是及格;后期再好,也不一定能及格。
有了这样的观念铺垫来看PS,我们就能分辨什么是好的后期,什么是不好的。换句话说,好的后期是不会留下过重的痕迹的。而对于后期本身,唯一的目的就是还原现场,附加的目的才是讨喜的颜色和风格。
就如今的数码相机技术来看,宽容度成为了是之与视觉所不同的最大难题。在光比过大的环境之下,我们所拍摄的照片往往不尽如人意,其关键原因在与相机宽容度与视觉比起来太低了,不符合我们的视觉习惯。为了解决这样的问题,胶片时代就有了使用渐变灰镜来压低天空曝光,保持画面曝光平衡的做法。而渐变灰镜的价格不菲,如果要购买一片没有偏色的灰镜,价格动辄上千,更何况是多片?同时在镜头之前附加渐变灰镜也会引起画质下降。可幸的是,我们身处数码时代,后期PS成为了我们廉价、优秀的选择。运用PS来解决宽容度问题,优势很大:
1、避免损害画质
2、可以对任意细节进行局部调整,避免了GND的山体压暗老大难问题
3、廉价,预算瞬间少了几千
而它的最大缺点,也只是对于后期PS技术有着很高的要求。
PS后期曝光对于前期拍摄有一定的前提,就是要包围曝光——再各种曝光值下拍摄相同的照片,期间不能有任何抖动,要保证各照片的构图完全相同。由于是后期技术的探讨,我就不多提及前期拍摄的部分了。
我从国外网站上翻译了这篇教程——亮度蒙版。这是Tony Kuyper系列教程中的一部分,也是一切的基础。它能够更自然地处理曝光合成,使得画面更加柔和,接近视觉。学习教程的前提是你要有一定的PS和摄影基础,要理解Raw图像的特点,然后,不断尝试。
Luminosity Masks
亮度蒙版
Tony Kuyper 2006
引言
note:最近我做了一个 【PS的自定义面板】,能够更简单地实现创建和使用亮度蒙版,还有网站上的其他后期技巧。访问这个链接来了解面板的更多信息,同时了解工作原理。
亮度蒙版是影调调整的基石。它提供了一个简便的方案,即选取某图像的个特定的影调,在合适的条件下,对它进行单独调整。这个方法可以解决相机感光元件或胶片所拍摄的图像的宽容度局限,还可以纠正在图像转换当中的偏移影调。除了简化这些基本的画面调整之外,亮度蒙版也在以一种独特的角度来阐释光线。亮度蒙版使捕捉到的光线更加灵活多变,从而提供给摄影师更大的空间来使用Photoshop来进行个人风格的摄影创作。
我的每张照片都使用了亮度蒙版来制作,并且每张图常常使用多次。在过去几年里,我尝试了许多不同版本的蒙版,并且把他们变得越来越实用。虽然亮度蒙版是PS里创建出来的,但你在下拉菜单或者是工具栏里是找不到他们的。在这个教程中,我将会阐述这些蒙版的概念,教你如何用PS来创建他们,以及展示基本的使用技巧。其中,亮部和暗部作为两个基础蒙版,制作相对简单,但当许多影调混合的时候,就会随之变得复杂。在教程里,所有步骤都会解释清楚。虽说理解如何去制作亮度蒙版和所选择的影调非常重要,但它确实相当繁琐。所以,要在PS的工作流程中高效地使用这些蒙版,最好能创建一些宏来简化他的关键步骤。这些宏大大地简化了生成蒙版的步骤,省去了大量时间。在这个教程的最后一部分,我列出了我自己亮度蒙版的宏设置。不过我还是得敦促你花一点时间来好好理解这些蒙版是怎么制作的,同时,请务必动手操作。学习这网站上的其他教程对你也会很有用,这会让你形成自己的一套实用蒙版的思路,最后使你的照片独树一帜。
网站上的一些其他教程是影调调整概念的延伸,而亮度蒙版使得影调调整变成了可能。这第一个教程虽然只是在讲述一个基本的概念,但它所涵盖的内容却蕴含着无限的可能性。而其他的教程将会注重于蒙版可以用到的其他方面以及探索影调调整的其他技巧。
深入学习之前,我想提一下,我用的是Windows版的Photoshop CS。教学里的每一步指示所给的参数和一些数字都会是假定的。虽然每个步骤我都会解释清楚,但我不想让别人只是想着按部就班。如果你不懂PS,PS的参考书也可以帮助你,包括“用户指导”还有帮助菜单。但如果你很熟悉PS的话,就可以很快上手。另外,我个人很倾向于尽可能地使用快捷键,这些快捷键是由Shift、Ctrl和Alt同时按,或者同时按的时候再加按字母键、数字键的组合方式构成的。我所列举的快捷键会被编入默认键,因此如果你有自己的快捷键习惯,请你相应调整或者重新编排快捷键。Mac用户需要知道PC上的“Ctrl”等同于“Command”,“Alt”等同于“Option”;还有些是下拉菜单命令里所对应的快捷键,这些快捷键往往会比基本的键更复杂,所以我几乎不使用他们。我还很喜欢使用Windows经典的灰色作为我程序的背景色,因此截图可能会看起来比较老气。
下图是一张我近期拍摄的砂岩,这张图使用了许多亮度蒙版的技巧,这些技巧都会在教程里面谈到。这张图里还用到了亮度笔刷(这是一个运用亮度蒙版的更先进的方法,会在其他教程中谈到)还有饱和度蒙版。
Image created using luminosity masks, rollover=no masks
Introduction
NOTE: I recently developed a custom actions panel that makes creating and experimenting with luminosity masks, as well as the other techniques on this website, much easier. Please visit this page for more information about the custom Photoshop panel and how it works.
Luminosity masks are the cornerstone of tone-based image adjustments. These masks provide a convenient way to select specific tones in an image which can then be altered as the user sees fit. They have the ability to overcome shortcomings in the tonal values that were captured by the camera or film and to correct tones that shifted during image manipulation. Beyond simplifying these standard adjustments, however, luminosity masks also encourage a very individual approach to interpreting light. Luminosity masks make the captured light incredibly flexible and thereby provide the artist photographer unique opportunities to use Photoshop to explore their personal vision through photography.
I use luminosity masks in every image I make, usually multiple times. Over the years I’ve created several different versions of the masks that have made them more useful. While luminosity masks are created in Photoshop, they aren't available from the drop-down menus and can't be created with tools in Photoshop's Tools palette. This tutorial will describe the masks, how to make them using Photoshop, and the basic way to use them. The two primary masks, "Lights" and "Darks", are relatively easy to create. From there, however, it becomes more complex as the various selections are intersected and subtracted. All the steps will be explained in the tutorial. While it’s important to understand the basics of how to create luminosity masks and the tones they select, mask creation can be a bit cumbersome. So, to efficiently use the masks in a Photoshop workflow, it’s usually best to create a set of Photoshop actions to do all the key strokes. Actions greatly simplify the process of generating the masks; a couple of clicks and you're done. I make my personal set of actions to create the luminosity masks available on the last page of the tutorial if you’d like to use them. However, I would urge you to take the time to gain a good understanding of the process by which the masks are created and to actually practice making them. It will be useful when reading the other tutorials on this website and will allow you to develop a very personal approach to employing the masks, which, in the end, will make your images more distinctive.
Several of the other tutorials on this website are an extension of the concept of tone-based adjustments that the luminosity masks make possible. While this first tutorial will provide the basic concepts, there is a wide range of possibilities beyond what it can cover. The other tutorials will look at additional ways that the masks can be used as well as exploring other techniques for tonal adjustments. Please visit them when you have time. The "tutorials" link in the header of each page will take you to the tutorial table of contents.
Before going too far, I should mention that I work on a Windows-based computer using Photoshop CS. The instructions in this tutorial will be given with those parameters in mind. Some facility with Photoshop will be assumed. While the details of the processes will be explained, I won't attempt to provide definitions of every Photoshop term or how to perform common steps. There are many reference guides to Photoshop that can help you, including the User Guide and the embedded "Help" menu in Photoshop, but if you've worked (or played) with Photoshop, you're probably familiar enough with the program to do the necessary steps. Additionally, I prefer to use Photoshop shortcut keys whenever possible. These are a combination of the Shift, Ctrl, and/or Alt keys being held down at the same time and, while continuing to hold them down, hitting a letter, number, or symbol on the key board. The ones I list will be the defaults that come programmed into Photoshop. If you've altered your shortcut keys to change the defaults, it's assumed you know what your corresponding shortcut is or can at least restore the defaults. Mac users will know that "Ctrl" on a PC is the same as "Command" on a Mac and that "Alt" on a PC is the same as "Option" on a Mac. There are usually drop-down menu commands that correspond to the shortcut keys, but these often become more complex than the shortcut keys, so I generally don't use them. I also like the classic Windows look to my programs with neutral gray colors, so the screen captures might look a little old-fashioned.
Below is a recent sandstone detail image that incorporates many of the luminosity masking techniques discussed in this tutorial. Luminosity painting (a more advanced way of using luminosity masks and one discussed in another tutorial on this website) and saturation masking were also used to develop this image. Roll over the image to see how it looks when the adjustment layers that use luminosity masks are turned off.
Section1:最基础的蒙版——亮部
亮度蒙版无非就是图像亮部上的选区。最基础的亮部蒙版,就是选取图像亮部成比例的像素。这里有三个不同的方法来制作亮部蒙版(图1)。我罗列了这三个方法,但你只需选择一种来创建选区。
1.Alt+Ctrl+~。如果使用的是CS4以后版本,现在快捷键改为Alt+Ctrl+2。
2.按住Ctrl,然后鼠标点击RGB通道。
3.选择RGB通道,把它拖到通道底部的“作为选区载入”的图标上。
图1
然后选区附近的选区点就会出现(图2)。由于Photoshop只有在像素至少50%被选中的情况下会出现选区点,而选区又是基于图像的亮度的,所以选区点只会在等同于50%灰或更亮的灰度的像素下才会出现。我之后会讲到这种情况的更多细节,现在只需要知道这些选区点所组成的选区很接近图像的亮部。
图2
当你已经创建了图像亮部的选区后,你应该把他们储存下来。步骤为:
1.点击通道面板下方的“将选区储存为通道”,然后一个叫做“Alpha 1”的通道会出现在面板中。(图3)
2.双击 “Alpha 1”通道,把他重命名为 “Lights” (亮部)。(图4)
3.点击RGB通道,然它变为可见的,还原有色的图像。(图4)
4.Ctrl+D取消亮部的选区
图3
图4
就这么简单,亮度蒙版中的图像的亮部就这样提取出来了。虽然费了许多笔墨,但当你动手操作的时候你就会发现相当简单。
从技术上讲,上述步骤所创建的其实是选区的Alpha通道。在它被运用到图层中之前,他不会成为蒙版。然而,蒙版和Alpha通道看起来完全想同,他们只是被放在不同的面板中而已,所以之后我会在两处都使用蒙版这个词。
The Basic Mask—"Lights"
Luminosity masks are nothing more than selections based on the brightness values of the image. The basic luminosity mask, called "Lights", selects pixels in proportion to their brightness in the image. There are three different ways to create this basic luminosity mask (Figure 1). I'll list all three alternatives, but you only need to do one of them to create the selection.
1.Type Alt-Ctrl+~. Hold down the Ctrl and Alt keys and hit the "tilde" which is just to the left of the number "1" key on the US keyboard. If you don’t have a US keyboard, use alternative 2. or 3. If using CS4, CS5, or CS6 this option is now Alt-Ctr+2.
2.Ctrl+click the RGB channel. Hold down the Ctrl key and click thumbnail image of the RGB channel.
3.Drag the RGB channel to the Load Selection button at the bottom of the Channels palette.
Figure 1
The marching ants appear on the image to define the selection (Figure 2). Since Photoshop only puts marching ants around pixels that are at least 50% selected, and since this selection is based on the brightness of the image, the marching ants only appear around pixels that are equivalent to 50% gray or brighter. I'll discuss this in more detail later. For now it should be obvious that the marching ants are enclosing the lighter areas of the image.
Figure 2
Once you've created the selection of the light areas of the image, it's a good idea to save it. To do this:
1.Click the Save Selection button at the bottom of the Channels palette. A channel called "Alpha 1" will appear in the Channels palette (Figure 3).
2.Double click on the name "Alpha 1" and type "Lights" and then hit the ENTER key to rename this channel (Figure 4).
3.Click the RGB Channel to make it active and to restore the color view of the image (Figure 4).
4.Type Ctrl+D to turn off the marching ants.
Figure 3
Figure 4
That's it! This is all that's needed to create the luminosity mask for the light areas of the image. It took a bit of writing to explain, but once you try it you'll see how easy it really is.
Technically, what was actually created in the above steps was an alpha channel of the selection. It won't actually be a mask until it's applied to a layer in the Layers palette. However, masks and alpha channels look entirely the same, they just reside on different palettes, so I'll be using the term "mask" to describe both from here on.
Section2:理解蒙版
为了体会这有用的蒙版和其他的亮度蒙版,我觉得理解到底什么是蒙版,蒙版的作用何在是很有必要的。在PS里,选区往往是用快速选择工具、魔棒工具和锁套工具来选区的。通常情况下,这些选区工具会创建纯黑或者纯白的蒙版。也就是说,如果你在使用完这些选区工具后,按下通道面板底部的 “将选区储存为通道”选项,蒙版会以纯黑或者纯白的颜色,以确定的锐利的边缘填充。在很小的局部,模糊、羽化和边缘柔化抗锯齿可以引入一些灰调,但在大部分的填充色中,蒙版仍旧是几乎纯黑或者纯白的。(图5)
图5
蒙版常常被用在图层混合中,而蒙版的法则是“白色显现,黑色隐藏”。也就是说蒙版中的纯白部分会让图层中对应的像素完全显现在图像上;纯黑部分则会“遮挡”那些对应的像素显示出来。这里需要注意,黑色蒙版的“遮挡”效果只是针对蒙版作用的那个图层。如果像素被“遮挡”了,Photoshop会按顺序向下显示未被遮挡的可显示的像素。而蒙版的黑色区域实质上就是告诉Photoshop去寻找下方的图层来显示应有的像素。蒙版的灰色部分意味着图像的像素以一定比例来显示灰度。比如,一个50%灰的蒙版就代表着图层上的像素以其一半的透明度显示出来,同时Photoshop会在下方的图层之中寻找到另一半透明度的像素。更深灰度的蒙版表示显示更少比例的作用图层,更浅灰度的表示显示更多比例。
现在就更深入了解我们所创建的“亮部”蒙版。点击“Lights”通道的缩略图,或者旁边的“Lights”通道名,蒙版会显现在Photoshop的主图像区域中。(图6)你可以看到这是一张包含了极少纯白和纯黑的完美的中灰影像的图片,是由完美反映了图像亮度的灰部所构成的。当此蒙版被应用到调整层中,它会显示出图像中最亮的像素(白色部分显现出来),同时按比例地减少深色像素的图像的显示(黑色部分隐藏)。这就引出了亮度蒙版的最重要的特性之一:亮度蒙版完全是自动羽化的。图上的效果会被显现出来,但是无法说清是从哪里开始哪里结束,因为它们没有生硬的边缘,也不用努力尝试去创建一个完美的选区。由于亮度蒙版是从图像本身创建的,它们以精确的比例保留和反应了图像所有的暗部和亮部的层次。
图6
Understanding Masks
To appreciate the usefulness of this mask and other luminosity masks, it's important to understand exactly what masks are and how they work. Selections are normally created in Photoshop using the Marquee, Magic Wand, and Lasso tools. Typically these selection tools create pure black and white masks. That is, if you were to hit the "Save selection" button on the Channels palette after using one of these selection tools, the mask would be filled with only pure black and pure white with sharply defined edges. Blurring, feathering, and anti-aliasing can introduce some gray tones for a less abrupt transition, but for the most part, the mask remains mostly all black and white (Figure 5).
Figure 5
Masks are routinely used in combination with layers in Photoshop, and the rule for masks is that "white reveals and black conceals." Pure white in the mask allows the corresponding pixels on the layer to be completely visible in the image. Pure black on the mask blocks the corresponding pixels on the layer from appearing in the image. It's important to understand that the blocking effect of black in the mask only occurs on the layer to which the mask is applied. If pixels are blocked from appearing on one layer, Photoshop sequentially looks down to the layers below to find unblocked pixels it can display. Black areas of the mask essentially tell Photoshop to look lower in the layer stack for what the pixel should look like. Shades of gray in a mask allow pixels to appear in the image in proportion to how light or how dark the gray value is. A mask that is 50% gray, for example, allows pixels on that layer to be visible in the image at half their normal opacity. Photoshop will have to find the other half from unblocked pixels deeper in the layer stack. Darker gray values in the mask allow proportionally less of the layer to show and lighter gray values proportionally more.
So now let's take a closer look at the "Lights" luminosity mask that was created. By clicking on the thumbnail image of the "Lights" channel or on the word "Lights" to the right of the thumbnail, the mask itself is now visible on the main image area in Photoshop (Figure 6). You can see that it is a perfect grayscale positive of the image and contains very little pure white and pure black. It is composed of shades of gray that perfectly mirror the brightness values in the image. As such, when this mask is applied to an adjustment layer, it will reveal the effect of the adjustment most on the brightest pixels in the image (white reveals) and proportionally less as the pixels get darker (black conceals). This leads to one of the most important properties of luminosity masks: they are completely self-feathering. The effect on the image will be obvious, but there will be no way to tell where the effect begins and where it ends. There are no hard edges like with Photoshop's selection tools and no need to try and make a perfect selection. Because the luminosity mask was created from the image itself, it has the perfect gradation of shades to insure that each and every pixel will be affected in exact proportion to its brightness.
Figure 6
Section3:使用“Lights”蒙版
要了解“Lights”蒙版是如何工作的,最好的方法就是看我在论坛上面贴的那张叫“Zion Narrows”(锡安的峡湾)的图片。有很多评论都说这张图看起来有点过曝了,也就是说图像的亮部看起来有点太亮了。所以“Lights”蒙版成为了一个可行的解决方案。我只需调整一下蒙版,对图像亮部进行压暗,就能修正这些过曝的部分,因为蒙版会对应地显示这些调整部分来遮挡。同时,这样的方法也保护了图像的暗部,使它不会显得过暗,因为蒙版会更深,从而隐藏这些区域。换句话说,蒙版使得这样的调整只影响到图像的亮部,同时保护了图像的暗部。“Lights”蒙版的使用步骤如下:
首先,创建“Lights”蒙版,方法我在第一部分中已经详细说明。
其次,也是非常重要的一步,确认蒙版是以选区的形式加载的。如果你在用我的宏(会在教程的最后一部分中提供)来创建亮度蒙版,蒙版创建好了,放在了通道面板上,也以合适的名字命名,然而这却不是活动的选区,因为周围没有选区点。事实上,为了在调整层上使用亮度蒙版,你必须加载它,使其变为一个活动的选区。你可以通过下列任何一个方法来加载:(图7)
按下Alt+Ctrl+数字(数字为通道所对应的数字)。
将通道拖到面板底部的“作为选区载入”按钮上。
Ctrl+点击图像缩略图(注意:不要点在前方的眼睛图标上面,这不会起作用)
图7
当选区点再次出现,切换到图层面板上。在面板的底部有一个半黑半百的按钮“创建新的填充或调整图层”。点击它,然后在菜单中选择“曲线”。(图8)
图8
一个新的图层马上就会显示在图层面板中,旁边会对应出现匹配“Lights”蒙版的蒙版,它也属于活动选区。同时”曲线“面板也会出现。(图9)
图9
在曲线面板中,我们对图像的高光部分进行压暗,然后点击确定。图10中的曲线图和旁边的效果图就是我做的调整和调整前后的区别。蒙版的“白色显现”法则保证了对于图像的调整只会作用在图像的亮部。先比之下,我也展示了隐藏蒙版后的图像。虽然在显示器上看得不清楚,但如果你仔细看,你可以看出来在没有显示蒙版的情况下,黑色部分会显得更黑。
图10
不要忘记在用亮度蒙版创建调整图层的时候,在调整图层上一定要有活动的选区。如果用我的宏的话,必须在点击“创建新图层”之前以选区的形式加载亮度蒙版(图7)。大多数情况下一旦选区点出现就证明了选区被激活,但有时候可能不是这样,我会在之后来解释这种情形。如果没有活动的选区,调整图层上本应出现蒙版的地方就会出现一大块纯白的方形,而这块方形会使你的调整运用到图像的所有像素上去。
Using the "Lights" Mask
A good way to see how the "Lights" luminosity mask works is with an image called "Zion Narrows" that I posted in an online discussion/critique forum. There were several comments that it looked a little overexposed. This suggested that the light areas of the image might be a little too bright, so using the "Lights" mask was one possible solution. An adjustment through the mask would allow me to correct this perceived brightness by darkening the image's light areas since the mask would be correspondingly light and revealing of the adjustment. It would at the same time protect the shadows from getting too dark since the mask would also be darker and therefore concealing of the adjustment in these areas. In other words, the mask allows the adjustment to affect predominantly the light areas of the image while at the same time sparing the dark areas. The process for using the "Lights" mask is relatively straightforward and goes like this:
First create the "Lights" mask as previously described in the The Basic Mask—"Lights" section.
Then, and this is very important, make sure the mask is loaded as a selection. If you're using my actions (available at the end of this tutorial) to create a luminosity mask, the mask is created, placed on the Channels palette, and given the proper name. However, it is not an active selection; there are no marching ants. In order to actually use the luminosity mask with an adjustment layer, it is necessary to properly load it to make the mask an active selection. This is done using any one of the following methods (Figure 7):
·Type Alt-Ctrl+number. Hold down the Alt and Ctrl keys and type the number of the mask's corresponding channel in the Channels palette (Alt-Ctrl+4 in this case).
·Drag the channel to the Load Selection button at the bottom of the Channels palette.
·Ctrl+click the thumbnail image or the channel name. (NOTE: Do not Ctrl+click on the eyeball square to the left of the thumbnail image as this does not load the channel as a selection.)
Figure 7
Once the ants of the selection are marching again, move to the Layers palette. At the bottom of the layers palette is a half white/half black circle which is the "Create new adjustment layer" button. Click it and choose "Curves . . ." from the pop-up menu that appears (Figure 8).
Figure 8
A new layer immediately appears on the Layers palette with a mask in place that matches the "Lights" mask, which was the active selection. Simultaneously a Curves dialog box appears (Figure 9).
Figure 9
Make the adjustment in the Curves dialog box to darken the highlights and click "OK". Figure 10 shows the curve I chose and the results with the mask in place. The "white reveals" rule for masks insures that the adjustment occurs mainly in the light areas of the image. For comparison, I've also shown the results with the mask disabled. Although it might be difficult to see on a monitor, if you look closely you should be able to make out that without the "black conceals" moderating effect of the mask, the dark areas in the image get significantly darker as a result of the adjustment.
Figure 10
Don't forget that when creating adjustment layers using luminosity masks, there must be an active selection at the time that the adjustment layer is created. If using my actions, be sure to load the luminosity mask as a selection (Figure 7) before clicking the "Create new adjustment layer" button. Usually there will be marching ants to indicate that there is an active selection, but sometimes there won't be, and I'll describe this situation later. If there is no active selection, a pure white square will appear on the adjustment layer where the mask should be. The white square will allow the adjustment to affect all pixels in the image equally, and not just those intended by the luminosity mask.
Section4:不同影调的不同蒙版
亮度蒙版的自我羽化特性是他们变得相当实用。这就如同每次都不费吹灰之力而创建了完美的选区一般,不用放大去看是不是每个像素都包含进去了,也不用反复对边缘进行调整,亮度蒙版包括了所有这些步骤。另外,“Lights”蒙版只是不同亮度蒙版的一个开始。如果你要调整图像的亮部,“Lights”蒙版会很有用,但暗部和中间调往往也需要进行调整。建立在“Lights”蒙版的基础上,针对图像不同亮度的大量的衍生蒙版也能够被创建。我仍旧在下面列举了,同时解释了他们的工作原理。根据这些信息,你可以创建一系列的Photoshop宏来创建各种蒙版。这一系列的宏预置可以在最后一章教程中找到。只要有了这些宏预置,你只要简单地运行一下就能使用了。
我选择了一张不那么抽象的,效果更直观的图片来阐述不同的亮度蒙版。当你看到这些蒙版的时候,往往会首先注意原图的灰度轮廓。这些蒙版的选区会包含完美的影调层次,所以对于蒙版的调整会无缝地融合进去。
图11展示了四个基于图像亮部的蒙版:
“Lights”(亮部)
“Light Lights”(明亮亮部)
“Bright Lights”(高光亮部)
“Super Lights”(超亮部)
(按字面意思翻译,明暗部分的划分可以参见亚当斯的区域曝光法)
图11
他们是通过相同蒙版的选区逐步交叉创建的。交叉是PS以两个选区的共同部分创建一个新的选区。要使用交叉,首先要以选区形式加载蒙版(Section3 图7)。当选区点出现的时候,Shift+Alt+Ctrl时点击要应用交叉操作的蒙版。“Bright Light”蒙版是由交叉“Light Light”蒙版自身而得来的,其他以此类推。每一次使用交叉命令都会使得亮部区域逐渐变窄。图11中的“Super Lights”蒙版中,蒙版中的深色部分已经基本变成黑色,只有在图像的最亮部分才能看到细节,换句话说,只有图像的最亮部分才会被调整图层所调整,而这种调整会被完美地羽化。
和“Lights”蒙版一样,“Light Lights”和“Bright Lights”也能出色地对图像的特定影调进行调整。“Lights”蒙版的暗处有许多灰部,这意味着通过蒙版的调整可以渗透进图像的暗处而不显得那么生硬。“Light Lights”和“Bright Lights”的调整就对暗部的影响越来越小了,因为在蒙版中图像的暗部是更深的灰色,甚至接近于黑色。
现在再来看暗部的蒙版。最基础的“Darks”蒙版就是简单地对“Lights”蒙版进行反选。(加载“Lights”蒙版选区后,按下Shift+Ctrl+I)。然后逐步交叉这些蒙版本身来创建图像更深的暗部蒙版。最后得到如下的几个蒙版:
“Darks”(暗部)
“Dark Darks”(深色暗部)
“Shadow Darks”(阴影暗部)
“Super Darks”(超暗部)
既然“Darks”蒙版是“Lights”蒙版的反选,那它们就成为了图像的反相图。每一步的交叉都使图像和选区变得更深。(图12)
图12
在“Super Darks”蒙版中,图像的亮部实质上已经变成黑色,这意味着应用在蒙版上的调整对他们不会起作用。和亮部的蒙版一样,暗部蒙版的调整会对亮部影响地越来越小。
要得到中间调会有点小麻烦,但这却是很实用的蒙版。你要先全选图像(Ctrl+A),然后再减去(Alt+Ctrl+点击你需要减去的蒙版)一个亮部和一个暗部的蒙版。当你移除了图像的亮色和暗色影调,剩下的就是中间调了。在后面提供的宏的蒙版里,我逐步删除了各种亮部暗部蒙版,得到了不同的中间调,如下:
“Basic Mid-Tones”(基本中间调)=全图-“Light”-“Darks”
“Expanded Miad-Tones”(扩展中间调)=全图-“Light Lights”-“Dark Darks”
“Wide Mid-tones”(宽中间调)=全图-“Bright Lights”-“Shadow Darks”
“Super Mid-tones”(超中间调)=全图-“Super Lights”-“Super Darks”
图13表示了中间调蒙版在逐渐变亮,因为中间调选区中的像素在逐渐变多。由于亮部和暗部蒙版众多,你可以选择各种可减去的蒙版,创建更多中间调蒙版。这里所列举的是一些比较常用的,同时也是比较基本的蒙版。对于不同的影调,你在中间调蒙版中可以减去或增加(Shift+Ctrl+点击)额外的暗部或亮部蒙版。根据我的经验,最常用在中间调调整中的蒙版是“Basic Mid-tone”和“Expanded Mid-tone”。“Wide”和“Super Mid-tone”蒙版在混合蒙版中会比较好用。
图13
“Basic Mid-tone”蒙版是我最喜爱的亮度蒙版之一。依据图像关系,蒙版会显得接近黑色,或者颜色非常深。所以要创造漂亮的效果,需要用一个比较陡的S型曲线来调整。事实上,你可以把1/4影调地方的曲线拉到最低点和最高点,把S型曲线调整为倒Z型。这对于图像来说只是一个小小的调整,但带来的效果确实很漂亮。在右图中,调整完的图像就有一种富士Velvia反转片的效果。可以说这种调整会给图像带来完美的对比度和饱和度。(图14)
图14
当你创建了亮度蒙版以后,图15所示的对话框会跳出来。对话框说:透明度低于50%的像素的选区点不会显示出来。这不代表这里没有选区!对于某些蒙版,只有40%或者20%的透明度的像素也能起作用。这样的蒙版看起来就会显得颜色很深,甚至接近黑色,“Basic Mid-tone”蒙版就是一个很好的例子。即使蒙版加载选区的时候没有选区点,那些作用于蒙版上的调整依然会出现,并且完美羽化。你可能要放大来仔细观察图像应用调整后的变化,但亮度蒙版确实已经根据你的预期来合适地调整影调了。所以如果对话框弹出来,点击“是”,然后继续下一步。
图15
Different Masks for Different Tones
The self-feathering feature of the luminosity masks makes them incredibly useful. It's like making the perfect selection each and every time with no effort at all. No zooming-in to make sure all the necessary pixels are included in the selection and no need to go back and touch up the edges of selections after the adjustment is made. The luminosity mask takes care of all that. In addition, the "Lights" mask is only the starting point for the different types of luminosity masks that can be created. The "Lights" mask is useful if you want to adjust the light areas of the image, but the shadows and mid-tones frequently need adjustment too. From the basic "Lights" luminosity mask, a large number of additional masks can be generated that target these other brightness levels in the image. I'll list them below and describe how they are made. Using this information you should be able to make a series of Photoshop actions to create the various masks. Information on how to obtain a set of actions for all the luminosity masks is available on the last page of the tutorial. With an action set, you simply need to run the action for a particular mask and it's ready to use.
I've chosen a different image to illustrate the various luminosity masks, one that is less abstract and therefore easier to see the features in the masks. As you look at the various masks, you will always see a grayscale outline of the original image. Selections from these masks, as a result, will have the perfect tonal gradation so that adjustments made using the masks will blend in seamlessly.
Figure 11 shows the four masks that target the bright areas of the image:
·"Lights"
·"Light Lights"
·"Bright Lights"
·"Super Lights"
They are created by progressively intersecting selections of the same mask. Intersection is when Photoshop creates a new selection by finding the pixels that two selections have in common. To use it, load a mask as a selection as described in Figure 7 in the Using the "Lights" Mask section. Once the ants are marching, Shift-Alt-Ctrl+click on the same mask to do the intersection operation. In this way, the "Light Lights" mask comes from intersecting the "Lights" mask with itself. The "Bright Lights" mask comes from intersecting the "Light Lights" mask with itself, and so on. Each gradually narrows the pixels selected to brighter and brighter areas of the image. Check the "Super Lights" mask in Figure 11. Dark values in the mask are essentially black. Details can only be seen in the lightest values of the image, so only the very lightest areas will be affected on an adjustment layer with this mask in place. Still, the light areas of the image can be seen as a grayscale positive in the mask which tells you that the selection generated from this mask will be perfectly feathered for whatever adjustments are made using it. (NOTE: In the latest version of the actions to create the luminosity masks, an "Ultra Lights" mask has been added. It's created by intersecting the Super Lights selection with itself. The resulting selection selects the only very brightest tones in the image.)
Figure 11
While the "Lights" mask would seem like a good one to use in adjusting the light areas of the image, "Light Lights" and "Bright Lights" often work better. There is a lot of gray in the dark values of the "Lights" mask, so adjustments through this mask significantly bleed into the image's dark values. The "Light Lights" and "Bright Lights" frequently do a better job of isolating the adjustment to just the light values since the dark values of the image are darker gray or even black in these masks.
Now for the darks. The primary "Darks" mask is simply the inverse of the "Lights" mask (Shift-Ctrl+I after loading the "Lights" mask as a selection). Then once again progressively intersect the masks with themselves to create narrower and narrower selections of the dark areas of the image. The resulting masks are called:
·"Darks"
·"Dark Darks"
·"Shadow Darks"
·"Super Darks"
Since the "Darks" luminosity mask is the inverse of the "Lights" mask, these are all negatives of the image. Each progressively restricts the selection to darker and darker image pixels (Figure 12). In the mask for the "Super Darks", bright areas in the image are essentially black meaning they'll remain unaffected by any adjustment applied using the mask. In a manner similar to the masks for the light areas, "Dark Darks" and "Shadow Darks" often work best for isolating adjustments to the dark values in the image. (NOTE: The latest version of the actions to create the luminosity masks also contains an "Ultra Darks" mask, created by intersecting the Super Darks selection with itself. The resulting selection selects the only very darkest tones in the image.)
Figure 12
The mid-tones are a little trickier to get at, but lead to some very useful masks. You have to first select the entire image (Ctrl+A) and then subtract off one light and one dark mask. Subtraction is accomplished by an Alt-Ctrl+click on whatever mask you want to subtract. When you remove the light and dark tones of an image, you're left with mid-tones. For the masks included in the downloadable actions, I've chosen to progressively subtract the masks in the order they're listed above. Here are the mid-tone masks:
·"Basic Mid-Tones" = "Lights" and "Darks" subtracted from the entire image
·"Expanded Mid-tones" = "Light Lights" and "Dark Darks" subtracted from the entire image
·"Wide Mid-tones" = "Bright Lights" and "Shadow Darks" subtracted from the entire image
·"Super Mid-tones" = "Super Lights" and "Super Darks" subtracted from the entire image
Figure 13 shows that the masks for the mid-tones get progressively lighter as more and more pixels are included in what the selection defines as a mid-tone. You could obviously choose a variety of ways to make a mid-tones mask since there are four each of the dark and light masks to choose for subtraction. The ones listed here are a good starting point. To target different tones, you can always subtract or add (Shift-Ctrl+click) additional dark and light masks to the initial mid-tones selection. My experience is that the "Basic Mid-tones" and "Expanded Mid-tones" masks work well for most mid-tones adjustments. The "Wide" and "Super Mid-tones" can be useful when creatively combining masks. (NOTE: The newly added "Ultra Lights" and "Ultra Darks" selections also make possible an "Ultra Mid-tones" selection. It's created by first selecting the entire image, and then subtracting the Ultra Lights and the Ultra Darks. However, because the tonal range of the Ultra Lights and Ultra Darks is so narrow, the tonal range of the Ultra Mid-tones is so broad that its usefulness in making targeted tonal adjustments is limited. For combining masks, the Ultra Lights and Ultra Darks work best for making "subtracted masks" which are explained elsewhere in the tutorials.)
Figure 13
The "Basic Mid-tones" mask is one of my favorite luminosity masks. Depending on the image, the mask for it will appear nearly black or very dark. It takes an extremely steep S-curve in the Curves dialog box applied through this mask to create a noticeable change in the image. In fact, you can pull the quarter tone values to their respective bottom and top positions, essentially making the S-curve a backwards Z-curve, with only a small change to the image. But what a beautiful change it is! For the right image, this adjustment is similar to taking the picture with Velvia. It's often provides the perfect pop to contrast and saturation (Figure 14).
Figure 14
As you create luminosity masks, the dialogue box in Figure 15 may pop up. This dialog box is saying that because less than 50% of any pixel's opacity is selected, the marching ants won't appear. It does not, however, mean that there is no selection. For some luminosity masks, having only 40% or even 20% of pixel opacity selected works just fine. When you add, subtract, and intersect luminosity masks, it's quite possible to create one where no pixels are more than 50% selected. Such a mask will appear very dark gray or even black. The "Basic Mid-tones" mask is a good example. Even though there are no marching ants when the mask is loaded as a selection, adjustments through the mask will still occur and be perfectly feathered. You may need to stretch, push, or pull adjustments to the extreme to see a noticeable difference in the image, but the luminosity mask will be doing its job of properly targeting the intended tonal values. So if the dialog box shows up, just click "OK" and continue.
Section5:实验是一切的关键所在
对于亮度蒙版的创建和使用没有完美的公式可以套用。如果某个模板很接近你所需的效果而用起来却不起作用,你可以使用更广或更窄影调的模板来做调整。如同其他的Photoshop的操作一样,尝试和失败会一直伴随着你。用图层来调整的好处就是你的损失将会变得很小,因为如果你不满意某个效果,你可以直接删除图层,而不会影响到其他的调整。而用宏来创建蒙版的优势是高效,对于50M以下的图像,虽说自动处理多步骤会有一些卡顿,但他们依然能很快速地创建模板。
你可以通过蒙版的叠加和减去来控制特定影调。蒙版可以轻松地把阴影中的细节补救回来,同时他们既可以被应用在有图像的层上,也可以用在调整层上。
我自己没有尝试过Photoshop的HDR功能,但我常常把RAW格式的图像转成亮部和暗部图像,然后用蒙版将它们分开调整。
曲线调整在这里只是示范,你还可以用其他的调整图层来调整图像,比如色相饱和度,色阶或者照片滤镜。
当你需要的影调正好与选区相反的时候,对蒙版的选区进行反选操作也是一个不错的方法。正如可以创建的亮度蒙版是无限多的,你在图像中使用它们的方法也是具有无限多可能的。
当你知道亮度蒙版的原理和作用以后,你的工作流程就会变得越来越程序化、简单化。图16展示了打开RAW后的图像还有“锡安的峡湾”图层调整处理后的最终效果图。其中采用的各种亮度蒙版都在图层蒙版上面标注清楚。做这张图花了我几个小时,每个调整层对于最终的效果来说都是一小步的增量,但最终的效果确实完全地还原了我当时在那个景点的所有印象,这点是相机本身做不到的。(注:现在可以在Examples这一章里下载这张图的psd文件了,这样你就可以更全面的来了解每个调整层的蒙版的作用了)
图16
你可以通过Shift+点击调整层上的蒙版来隐藏某个蒙版(图17),隐藏蒙版可以使你更了解这个特定蒙版对于图像影调起的特定作用。当蒙版隐藏后,他的缩略图上会出现一个红叉。当你使用蒙版的时候你会发现你的调整选择变多了,就像图14“基本中间调”中的Z曲线调整一样,你可以做出更多的更梦幻的调整。而隐藏了基本中间调的蒙版之后,图像就会变得不堪入目了。当你在试验亮度蒙版的时候,不要埋怨会花更多时间,因为你可能要不断注意蒙版的调整会带来什么,特别是含有许多深灰色调的蒙版。最后,做更多的极致调整也会更让你理解蒙版所带来的柔化功能。
图17
在许多情况下,比如上面的举例,每个带有亮度蒙版的图层只对图像起着微妙的作用,而如何根据你的风格来调整这些图层却是取决于你的。蒙版不是快速修复的插件,但对于摄影师来说却是能加入个人风格的绝佳工具,至少对我来说,它是一项伟大的发现。至此之后,我就很少用到Photoshop的传统选区工具来创建选区了,而且亮度蒙版所创建的选区也是更接近我的想法的。宏使得蒙版的创建变得更简单,我也很喜欢这种不破坏影调层次的调整方法。这毫无疑问是我所了解的影响后期的最有效的方法了。
工作流程中需要注意的:当你开始使用亮度蒙版的时候,多仔细观察通道面板,蒙版会在这里堆积。当某个蒙版达到预期效果或者已经被并入了调整层的话,你就可以删除它了。如果过多地在通道保存多余蒙版会增加文件的容量,所以养成好习惯,当你不需要它们的时候,请删除。
Experimentation is the Key
There is no perfect formula for deciding exactly which luminosity mask to create and use. If one mask gets you close to the effect you're looking for but doesn't quite work, you can use one with a wider or narrower range to better hit your target tonalities. Trial and error, like many operations in Photoshop, will always play a role. Working on layers makes experimentation lossless as you can simply discard the layer if it doesn't work. The advantage of using actions to create the masks is that it's relatively quick to generate them for images less than 50 mb, though there will be some delay as Photoshop automatically executes the steps in the action.
Adding and subtracting masks allow you many more options for targeting specific tones. The masks work great for pulling detail out of the shadows, and they can be used on pixel-containing layers as well as adjustment layers. I've not personally experimented with Photoshop's High Dynamic Range, but I have used the masks to easily blend the bright and dark areas of two separate pixel-containing layers after conversion of the RAW file to favor the light and dark areas of the image. While Curves adjustments were used for demonstration here, the masks work equally well with other adjustment layers like Hue/Saturation, Levels, and Photo Filter. Inverting a selection from a mask is also an option when you want to target tones that are the opposite of what a mask selects. Just as there are an unlimited number of luminosity masks when you start combining them, there is also an infinite number of ways to apply them to an image.
Once you get a feel for what luminosity masks can do, working with them becomes more automatic and quite easy. Figure 16 shows the raw conversion and the final version of the "Zion Narrows" image along with the set of layers needed to achieve the results. The various luminosity masks employed are noted on the labels for the layers. It took a few hours to get this worked out—each layer was only an incremental change towards the final image—but the final image definitely captures my impression of the place much better than what the camera offered.(Note: A downloadable version of this Photoshop image file is now available in the Examples section. It will allow you to take a closer look at the masks for each layer and the adjustments through the masks.)
Figure 16
One trick to help you appreciate the way a luminosity mask confines adjustments to specific tonalities is to disable the mask and watch the effect on the image. You disable the mask with a Shift+click on the mask itself on the adjustment layer (Figure 17). A red "X" appears over the mask when it's disabled. Without the moderating influence of the mask, the full force of the adjustment becomes visible. One thing you'll find when using the masks is that you can generally make much more dramatic adjustments, like the backwards "Z" Curves adjustment through the "Basic Mid-tones" mask in Figure 14. Disable the Basic Mid-tones mask there and the image becomes garishly unacceptable. As you experiment with luminosity masks, don't be afraid to push harder than you normally would on your adjustments to see what happens, especially if the mask contains a lot of black and dark shades of gray. Making more extreme adjustments will also help you appreciate the smooth blending that the masks facilitate.
Figure 17
In many cases, like the example above, each layer with a luminosity mask only provides a subtle change to the image, and it will be up to you to figure out how to build these changes into your personal vision of the scene. The masks are not a quick-fix plug-in, but they are one more tool for the artist photographer to use to add a personal touch to the scene. For me they have been a wonderful discovery. I rarely need to make selections with Photoshop's traditional tools anymore, and I find the results from luminosity masks much more to my liking. The actions make the masks easy to generate, and I like the way the tonal gradation of the masks allow adjustments to blend seamlessly and effortlessly into the image. They are without question one of the most effective ways I've found to manage light in the digital darkroom.
Workflow note: As you begin working with luminosity masks, keep an eye on the Channels palette. Masks tend to accumulate here. Once a mask has served its purpose or has been incorporated into an adjustment layer, it can be deleted. Saving a file with lots of masks on the Channels palette will definitely increase file size, so get in the habit of deleting masks from the Channels palette when they are no longer needed.
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