{"slug":"lum-mask-exposure-blending","title":"如何用亮度蒙版来做PS曝光合成？正确方法在这儿！","author":"Thomas看看世界","date":"2020-03-15","wechat":"https://mp.weixin.qq.com/s?__biz=MzI4NDA5MzE5NQ==&mid=2247490253&idx=1&sn=1beac184f261260a7a75adbc809dab16&chksm=eb81e4a9dcf66dbf1de5a242ff75dddc0ae35e0bc4008da7cafb9a7a6c01e21c43eacfab4c11&scene=21#wechat_redirect","blocks":[{"t":"h","x":"Thomas看看世界","xe":"Thomas Chu Photo"},{"t":"p","x":"亮度蒙版是一种重要的摄影后期处理工具，但如果不正确的使用，照片效果反而会变得很差。","b":false,"xe":"Luminosity masks are an important post-processing tool, but used incorrectly they can actually make a photo look worse."},{"t":"img","f":"img-02","w":1080,"h":717},{"t":"p","x":"在今天的视频教程中，Thomas会和大家分享一种局部应用亮度蒙版的方法，用来做曝光合成，选区调色都是极好的。","b":false,"xe":"In today's video tutorial, Thomas shares a method for applying luminosity masks locally — perfect for exposure blending and selective color work."},{"t":"h","x":"视频教程","xe":"Video Tutorial"},{"t":"bili","bv":"BV1K7411f7pv","bpic":"bili-1","bt":"如何用亮度蒙版来做PS曝光合成？正确方法在这儿！"},{"t":"p","x":"这一篇是上面视频的完整图文整理。上一期教程里 Thomas 用动作一键生成了亮一到亮七、暗一到暗七的亮度通道，这一期回答更关键的问题：怎么把通道变成蒙版、用到曝光合成里去。视频只有 7 分钟，但点破了一个大多数人都在犯的错误——亮度蒙版不做局部限制，直接刷满全图。下面按视频顺序拆成五步，配上关键帧截图，先看图建立流程，再到视频里听细节。","xe":"This is the fully illustrated companion to the video above. In the previous episode Thomas generated the luminosity channels (Lights 1-7, Darks 1-7) with a single action; this episode answers the more important question — how to turn those channels into masks for exposure blending. In just 7 minutes it calls out the mistake most people make: applying a luminosity mask globally with no local restriction. The five steps below follow the video's order, with keyframe screenshots — skim here for the framework, then dive into the video for the details.","b":false},{"t":"p","x":"先看成片。这是希腊圣托里尼的日落，两张包围曝光底片合成后的样子：太阳的细节、海面的反光、悬崖上小镇的暗部都在。整期教程做的就是下面这张图，核心只在一层「组蒙版」上。","xe":"Start with the result: a Santorini sunset in Greece, blended from two bracketed exposures — detail in the sun, reflection on the sea, and clean shadows in the clifftop village. The whole tutorial builds toward this one image, and the key is a single group mask.","b":false},{"t":"img","f":"v11","w":852,"h":480},{"t":"h","x":"01 素材：圣托里尼的包围曝光底片","xe":"01 The Source: Santorini Brackets"},{"t":"p","x":"案例是一组拍摄于希腊圣托里尼的夕阳包围曝光（视频 1:13 处）。第一张对高光曝光：稍稍欠曝，除了太阳本身，周边的云层和海面反光都没有过曝；第二张对阴影曝光：暗部非常干净、几乎没噪点，但天空和海面的反光已经过曝。一张保高光、一张保暗部，正是曝光合成的标准素材。","xe":"The case is a bracketed sunset set from Santorini, Greece (at 1:13 in the video). The first frame is exposed for the highlights: slightly underexposed, so apart from the sun itself the clouds and the sea reflection are not blown. The second is exposed for the shadows: the darks are clean and nearly noise-free, but the sky and sea reflection are clipped. One frame protects highlights, the other protects shadows — standard material for exposure blending.","b":false},{"t":"img","f":"v01","w":852,"h":480},{"t":"img","f":"v02","w":852,"h":480},{"t":"p","x":"把这两张合成，当然可以直接丢给 HDR 合成，但 Thomas 在这里演示的是用亮度蒙版来手动做——可控性更强，也是这期视频真正想教的方法（视频 1:50 处）。","xe":"You could simply feed both frames to an HDR merge, but Thomas demonstrates the manual route with luminosity masks — far more control, and the real subject of this episode (at 1:50 in the video).","b":false},{"t":"h","x":"02 选通道：把过曝区域选出来","xe":"02 Picking the Channel That Isolates the Clipped Area"},{"t":"p","x":"用亮度蒙版的第一步，是找到一个合适的亮度通道。先对最亮的那张欠曝图层运行亮度通道生成动作，得到亮一到亮七、暗一到暗七等通道（视频 0:32 处演示动作面板）。","xe":"Step one with luminosity masks is finding the right brightness channel. Run the channel-generating action on the brightest (underexposed) layer to get Lights 1-7, Darks 1-7 and the rest (action panel demonstrated at 0:32 in the video).","b":false},{"t":"img","f":"v03","w":852,"h":480},{"t":"p","x":"选通道的标准有三条：尽可能包括过曝的区域、同时又尽可能包括没过曝的区域、而且过渡要尽量自然（视频 2:11 处）。对着通道面板逐一观察，亮二和亮三都是不错的选择，都把高光过曝的区域很好地选了出来，Thomas 最终用了亮三。","xe":"Three criteria for picking a channel: it should cover the clipped area as fully as possible, include as much of the unclipped area as possible, and transition smoothly (at 2:11 in the video). Inspecting the panel, both Lights 2 and Lights 3 isolate the blown highlights well; Thomas goes with Lights 3.","b":false},{"t":"img","f":"v04","w":852,"h":480},{"t":"p","x":"转换动作是按住 Ctrl 键点击亮三通道，通道就变成了选区——蚂蚁线大致沿着天空和海面的高光分布（视频 2:37 处）。","xe":"The conversion is one shortcut: Ctrl-click the Lights 3 channel and it becomes a selection — the marching ants tracing the bright sky and sea areas (at 2:37 in the video).","b":false},{"t":"img","f":"v05","w":852,"h":480},{"t":"h","x":"03 错误示范：蒙版直接刷满全图","xe":"03 The Wrong Way: One Mask Across the Whole Frame"},{"t":"p","x":"接下来把对阴影曝光的那张（亮度信息更全的欠曝图）移到最上层，选中它的图层，点击「新建图层蒙版」，刚才的选区就自动转成了蒙版。天空和海面果然不过曝了——但如果到此为止，这恰恰是亮度蒙版的错误用法（视频 2:59 处）。","xe":"Next, drag the shadow-exposed frame (the brighter, detail-rich one) to the top of the stack, select it, and click Add Layer Mask — the selection converts into a mask automatically. The sky and sea are no longer blown. But stopping here is exactly the wrong way to use a luminosity mask (at 2:59 in the video).","b":false},{"t":"img","f":"v06","w":852,"h":480},{"t":"p","x":"问题有两处（视频 3:15 处）。其一，太阳的融合非常不自然：原来很亮的一张照片，硬融进一张欠曝的照片，亮度衔接必然生硬。其二，悬崖上那些只是有点亮的区域——本来并不过曝，蓝色的反光高光看起来非常舒服、很有立体感——也被蒙版一并「修复」了。不该修的地方也修了，这就是不限制蒙版作用范围的代价。","xe":"Two problems follow (at 3:15 in the video). First, the sun blends unnaturally: a bright frame forced into an underexposed one is bound to show a harsh brightness seam. Second, areas that were only somewhat bright — not clipped at all, their blue reflective highlights pleasant and full of dimension — get 'repaired' along with everything else. Fixing what didn't need fixing is the price of letting the mask run unchecked.","b":false},{"t":"h","x":"04 正确方法：分组加组蒙版做局部限制","xe":"04 The Right Way: Groups and a Restricting Group Mask"},{"t":"p","x":"解决办法是对亮度蒙版做局部限制：只让它作用于太阳和过曝的海面，而且只做轻微的曝光补偿。Thomas 用的方式是分组：新建一个图层组，把带亮度蒙版的图层拖进组里，再给组本身新建一个蒙版（视频 4:09 处）。","xe":"The fix is to restrict the luminosity mask locally: let it act only on the sun and the blown sea, and only as a mild exposure correction. Thomas's method is grouping: create a group, drag the luminosity-masked layer into it, then add a mask to the group itself (at 4:09 in the video).","b":false},{"t":"p","x":"理解组蒙版只需一句话：组是图层的集合，组蒙版会对组内所有图层的效果再做一层限制（视频 4:21 处）。组蒙版全黑时，组里所有效果归零、对画面没有任何影响；把它 Ctrl+I 反相成白色，组里的效果才会全画面生效。亮暗两级蒙版叠加，作用范围就被收得非常窄。","xe":"One sentence explains a group mask: a group is a set of layers, and its mask restricts everything inside it one level further (at 4:21 in the video). Fully black, the group's effect drops to zero with no impact on the image; invert it with Ctrl+I to white and the group's effect applies across the frame. Mask on mask stacks, and the working area becomes very narrow.","b":false},{"t":"img","f":"v07","w":852,"h":480},{"t":"p","x":"具体操作：选白色画笔，把不透明度降到 10% 左右，在组蒙版上慢慢涂抹太阳和海面那些真正过曝的区域（视频 5:06 处）；涂到合适的程度后，周边再把不透明度进一步降到 4%，换一支大画笔做柔和的过渡（视频 5:37 处）。","xe":"In practice: pick a white brush, drop the opacity to around 10%, and slowly paint over the truly blown areas — the sun and the sea reflection — on the group mask (at 5:06 in the video); for the surroundings lower the opacity further to 4% and use a large soft brush to ease the transition (at 5:37 in the video).","b":false},{"t":"img","f":"v08","w":852,"h":480},{"t":"img","f":"v09","w":852,"h":480},{"t":"h","x":"05 三层控制：自然合成的关键","xe":"05 Three Layers of Control: Why the Blend Looks Natural"},{"t":"p","x":"视频最后 Thomas 把两层蒙版去掉又加回，逐一解释它们各自的贡献（视频 5:56 处）。欠曝图层保留着天空的全部细节；亮度蒙版保证它只在很亮的区域被显示出来——只有过曝的地方才被选择；组蒙版再进一步限制，保证那些明明没过曝、却被亮度蒙版顺手选上的区域不受影响。","xe":"At the end of the video Thomas toggles both masks off and on, explaining what each contributes (at 5:56 in the video). The underexposed frame keeps all the sky detail; the luminosity mask makes sure it shows only where it is truly bright — only the clipped areas get selected; the group mask restricts further, protecting regions that were never blown yet happened to fall inside the luminosity selection.","b":false},{"t":"img","f":"v10","w":852,"h":480},{"t":"p","x":"第三层控制是那支低不透明度的画笔：刷进来的过程是慢慢的、渐进的，融合自然，不会出现没有亮度蒙版配合时那种非常生硬的亮度过渡。亮度蒙版选范围、组蒙版收边界、低不透明度笔刷做过渡——这就是亮度蒙版的最佳使用方法（视频 6:44 处）。","xe":"The third layer of control is the low-opacity brush: painting in gradually produces a natural blend instead of the harsh brightness transition you get without this setup. Luminosity mask picks the range, group mask tightens the boundary, low-opacity brush smooths the transition — that is the best way to use luminosity masks (at 6:44 in the video).","b":false},{"t":"quote","x":"1. 亮度蒙版做曝光合成，先对最亮的底片生成亮度通道，按「含过曝区、含未过曝区、过渡自然」三条标准选通道（本例亮三）；2. 通道 Ctrl+点击转选区，再转图层蒙版，但绝不能直接刷满全图——太阳融合生硬、次亮高光被误修复；3. 正确做法是分组并给组加蒙版，用 10%-4% 不透明度的白色画笔只把太阳和过曝海面刷回来；4. 亮度蒙版选范围、组蒙版收边界、低不透明度笔刷做过渡，三层控制才有自然的曝光合成。","xe":"1. For exposure blending, generate luminosity channels from the brightest frame and pick one by three criteria — covers the clipped area, keeps the unclipped area, transitions smoothly (Lights 3 here); 2. Ctrl-click the channel into a selection, then into a layer mask — but never apply it globally: the sun seams harshly and near-highlight detail gets wrongly 'fixed'; 3. The right way is a group with its own mask, painting back only the sun and blown sea with a 10%-4% opacity white brush; 4. Luminosity mask for range, group mask for boundary, low-opacity brush for transition — three layers of control make the blend natural."},{"t":"h","x":"练习文件与亮度蒙版动作下载：","xe":"Practice files and luminosity mask action download:"},{"t":"p","x":"百度云链接: https://pan.baidu.com/s/1V6knr5YfICsiOr37nRbk6g 提取码: es84","b":false,"xe":"Baidu Cloud link: https://pan.baidu.com/s/1V6knr5YfICsiOr37nRbk6g — extraction code: es84"},{"t":"p","x":"或腾讯微云链接：https://share.weiyun.com/51HPn0e","b":false,"xe":"Or Tencent Weiyun link: https://share.weiyun.com/51HPn0e"},{"t":"h","x":"摄影后期，思路和想法比PS技术更为重要。","xe":"In post-processing, ideas and vision matter more than PS technique."}],"titleEn":"Exposure Blending with Luminosity Masks: The Right Way"}