颜色涂抹笔刷引擎

颜色涂抹笔刷引擎

这个笔刷引擎通过涂抹和钝化来混合颜色，是一个能在上色流程中大展身手的强大引擎。

可用笔刷选项

颜色涂抹引擎的特有选项

颜色量

How much of the foreground color is added to the smudging mix. Works together with 涂抹长度 and 涂抹半径.

A variety of color smudge strokes in the Smear Mode with different opacities, smudge lengths and spacing. All are with 50% Color Rate. Left-hand set being the old algorithm and the right-hand set the new algorithm. The bottom two strokes are using the 颜色减淡 blending mode.

5.0 新版功能: The option Use new smudge algorithm greatly affects how the Color Rate works. With the old algorithm, the Color Rate will be affected by both smudge length and opacity, while with the new algorithm, Color Rate will only interact with Opacity.

At first glance, this may seem like it reduces nuance. But instead, the new algorithm simplifies brush creation, with it being far clearer which elements interact with Color Rate.

Same as figure above, but then in Dulling Mode.

Using the new algorithm, turning off the smudge length is all that’s needed to make a brush that is similar to the 像素笔刷引擎. This is useful as a starting point for brushes that only need a little smudge.

When using the gradient mode, the Color Rate will control the colored brush tip instead of a flat color.

Blending modes are applied when the color part is composed onto the smudge part. This effectively means that color smudge brushes with a blending mode other than 正常 will be greatly affected by Color Rate in addition to 间距 and opacity.

涂抹长度

Affects smudging and allows you to set it to Sensors. Smudging is greatly affected by 间距 as well as Opacity. The former controls how many dabs are placed, and thus how many samples are made. This results in a smoother result for Smear Mode, and a more opaque result for Dulling Mode.

There are two major types:

涂抹

Copies the area underneath the previous position of the brush onto the new position, taking opacity into account. This tends to result in a smear-effect.

Great for making brushes that have a very impasto oil feel to them. It’s recommended to have a low spacing for Smear, as this will result in a less grainy looking smear.

A variety of color smudge strokes in the Smear Mode with different opacities, smudge lengths and spacing. Left-hand set being the old algorithm and the right-hand set the new algorithm. The bottom two strokes are using the 颜色减淡 blending mode, which does not have any meaningful effect, given the 颜色量 is set to 0%.

钝化

Picks the color underneath the brush dab (using the Smudge Radius, if applicable), and first fills the whole dab with that before applying the color and the opacity. Named so because it dulls strong colors.

Using an arithmetic blending type, Dulling is great for more smooth type of painting. It’s recommended to increase the spacing on dulling brushes as much as possible without the stroke looking choppy, as it speeds up the brush without losing smudge quality. The resulting stroke can be made stronger by increasing the smudge radius or the opacity.

Same as above, but then for the Dulling Mode.

强度

Affects how much the smudge length takes from the previous dab its sampling. This means that smudge length at 100% will never decrease, but smudge lengths under that will decrease based on 间距 and Opacity.

Smear Alpha

Controls whether the transparency of the smeared pixels is taken into account when painting. This can be helpful to get a more opaque effect, as if laying down thick layers of paint, without losing the smudge effect.

Different strokes showing how smear alpha functions.

Smear Mode with Smear Alpha.
Smear Mode without Smear Alpha.
Dulling Mode with Smear Alpha.
Dulling Mode without Smear Alpha.
Dulling Mode without Smear Alpha, and 涂抹半径 set to 100%.

Use new smudge algorithm

5.0 新版功能.

The new smudge algorithm was initially introduced to allow lightness and gradient modes on the color smudge. But it allows for more: it is a little quicker, and it has a better separation between the 颜色量 and the Smudge Length.

常见误区：

Unchecking the smudge length function sets smudge length to 100% (not 0.00).
Opacity: Below 50%, there is practically no smudging left: keep opacity over 50%.

各选项的效果对比：

Spacing with Smearing: the lower the spacing, the smoother the effect, so for smearing with a round brush you may prefer a value of 0.05 or less. Spacing affects the length of the smudge trail, but to a much lesser extent. The strength of the effect remains more or less the same however.
钝化模式下的间距效果：间距越小，效果越明显。随意调低间距将把钝化效果变得过于明显，因为它拾取一种颜色后通过此颜色绘制的时间更长。间距也会直接决定了钝化作用痕迹的长度。
Both Smearing and Dulling have a “smudge trail”, but in the case of Dulling, the brush shape is preserved. Instead, the trail determines how fast the color it picked up is dropped off.

涂抹半径

此选项控制在钝化模式下涂抹采样半径的大小。

此选项的“效果强度”滑动条控制的是涂抹半径相对笔刷大小的百分比。你可以通过压感笔传感器来控制它的数值。下图从上到下依次为为涂抹半径为 0、100% 笔刷大小、200% 笔刷大小时的效果。可见涂抹半径越大，涂抹采样的范围就越广，得到的颜色就越接近采样区域的平均值。

A variety of brush strokes using 50% color rate, 50% smudge length and 50% opacity, but different smudge radii. The top stroke is in smear mode and thus smudge radius is not in effect.

在 5.0 版更改: It used to be possible to go beyond three time the size of the current brush. The smudge radius is now limited to the total size of the brush, but is also faster.

覆盖模式

Overlay is a toggle that determine whether the smudge brush will sample all layers (overlay on), or only the current one.

在默认状态下，颜色涂抹笔刷引擎只会拾取当前图层的颜色信息。在勾选覆盖模式后，它将拾取所有图层的颜色信息。

要注意的是，由于覆盖模式的涂抹会从下面的图层中拾取一部分图像，所以在涂抹之后再对下面的图层进行加工时，颜色很可能就会对不上了。

Paint Thickness

5.0 新版功能.

This affects how strong the lightness modes affect the current color. Because the Color Smudge Brush smudges, what actually happens is that the lightness part is painted into a separate height map. This prevents the shadows and highlights of the current lightness brush tip from being mixed into the smudge, which would have resulted in all smudges becoming white or black. The height map is discarded when switching brush engines, layers or tools. Because this heightmap only exists for the layer currently being edited, lightness brushes and paint thickness cannot be used together with 覆盖模式.

Image showing off different variations of Paint Thickness, with the top three strokes being in Smear Mode and the bottom three in Dulling Mode. Strengths are 100%, 50%, and 0% from top to bottom.

This has two modes, which change how the existing heightmap is interpreted:

Overwrite (Smooth out when low) existing paint thickness

Here the lightness value of the brushstroke overrides the value that was there before, effectively smoothing out previous paint if the thickness value is low. The Opacity setting will cause it to blend with the previous paint height, but that will also bring down the color. This mode is useful for a brush that can paint with thickness, but can also smooth out existing paint if you wish.

Paint over existing paint thickness (controlled by smudge length)

Here the lightness value blends with the previous values, based on the Smudge Length, as described above. It allows the kind of blending with previous paint height that Opacity allows in the Overwrite mode, but without affecting the color rate.

Image demonstrating the two modes, with the top strokes being Overwrite Existing Paint Thickness and the bottom strokes Paint over existing paint thickness. In both cases, a red stroke was laid with 100% paint thickness. Blue strokes were overlaid going from thin to thick. Notice how the Paint over existing type differs between 0% and 100% Smudge Length.

Hue, Saturation, Value

Identical to 色相、饱和度、明度 in the Pixel Brush Engine, this will adjust the current foreground color before it is mixed in via 颜色量. Introduced because this brush engine used to have a small rounding error leading to iridescent smears, which was fixed. Artists who liked this effect can now emulate it by enabling Hue, enabling Fuzzy Dab and disabling Pressure and finally setting Strength to 40%.

Top: without hue variance, Bottom: with hue variance.

Hue, Saturation and Value don’t affect brush-tips using the gradient mode.

笔尖

The Color Smudge Brush has all the same 笔尖 as the 像素笔刷引擎!

还是那句话，笔尖不透明度太低时会导致涂抹效果不明显。如果笔尖本身的不透明度较低，则应增加不透明度、涂抹长度、颜色量等选项的效果强度。

分散以及其他动态选项

The Color Smudge Brush shares a number of options with the 像素笔刷引擎.

不过由于涂抹的影响，两个引擎的同种选项会产生不同的效果。分散效果的区别尤其明显。下面的例子展示了分散选项在涂抹笔刷下的效果。上半部分为涂抹模式，下半部分为钝化模式。左边是分散度 50% 的效果，右边为加上了大小和旋转映射到随机度的效果。

注意事项：

Scattering is proportional to the brush size. It’s fine to use a scattering of 500% for a tiny round brush, but for bigger brushes, you may want to get it down to 50% or less.
上图的涂抹模式区域产生了一些横线，这是因为笔刷拾取到了蓝色矩形的边缘。
分散选项启用时，笔刷会拾取笔迹附近一定范围内的颜色，而不仅拾取笔刷下面的颜色。在下图中，尽管笔迹只经过了没有颜色的区域，却拾取到了位于路径附近的红、蓝色带的颜色。

颜色涂抹笔刷引擎使用教程

本节的部分内容较旧且与前面重复，但我们建议至少粗略阅读本教程的第一部分，因为它们从另外的角度解释了引擎的工作原理，可以帮助你更好地理解各个选项的作用。

Smudging and blending

本范例中的颜色量选项均为关闭状态。

关于形状和透明度动态的细节，可以参考像素笔刷引擎页面的可用选项介绍。

涂抹效果

简单涂抹操作：

选择颜色涂抹笔刷引擎，在”涂抹长度“选项中按需选择”涂抹“或者”钝化“。
关闭”颜色量“选项。
进行涂抹操作。在下面的例子中，上半部分为涂抹模式的效果，下半部分为钝化模式的效果。黑色的是笔尖形状。

请注意：在不透明度较低时，涂抹的效果不明显。在使用不透明度较低的笔尖时，可以通过增大涂抹长度和不透明度的效果强度来进行补偿。

涂抹模式的运用技巧

要想涂抹效果更加平滑，可以降低笔尖的间距。请记得间距与笔尖大小是成比例的。小型笔刷可以使用 0.10 的间距，但更大的笔刷则应使用 0.05 甚至更小的间距。

钝化模式的运用技巧

减小间距会使涂抹效果变得更加明显，所以要多加试验找到所需的平衡点。中等大小的圆形笔刷可以使用 0.10 左右的间距。
和涂抹模式不同，钝化模式的涂抹痕迹会体现笔刷的形状，它也不会像涂抹模式的痕迹那样慢慢变小。你可以把笔刷大小映射到淡化传感器来模拟这种效果。

带有肌理的混色效果

你可以通过颜色涂抹引擎营造带有颜料肌理的混色效果。你可以单独或者联合使用”旋转“和”分散“选项做到这一点：

打开旋转选项，映射到距离或者随机度。
打开分散选项
- For most mid-sized brushes you will probably want to lower the scatter rate to 50% or lower. Higher settings are okay for tiny brushes.
- Note that Scatter picks colors within a certain distance, not the color directly under the brush (see 笔尖).
Optional: Pile on size and other dynamics and vary brush tips. In fact, the Color Smudge Brush is not a blur brush, so smudging is not a very good method of “smooth” blending. To blend smoothly, you’ll have better luck with:
在渐变的路线上先绘制中间色调，我们会在后面对此进一步介绍。
或者通过羽化选区使用模糊滤镜，此方法也会在页面的末尾进行介绍。

I’ve tried to achieve smooth blending with Color Smudge Brush by adding rotation and scatter dynamics, but honestly they looked like crap.

However, the Color Smudge Brush is very good at “textured blending”:

总的来说，你可以先画出要混合的颜色，然后在它们上面添加带有肌理的过渡效果。

Coloring

本范例中的颜色量选项均为开启状态。

图层选项

Before we get started, notice that you have several possibilities for your set-up:

第一种：在同一图层绘制底色和光影，效果参考下图上半部分的左一 (涂抹) 和左三 (钝化)。
第二种：在不同的图层上绘制底色和光影，可以通过继承不透明度功能把光影区域限制在底色区域内，效果参考下图上半部分的左二 (涂抹) 和左四 (钝化)。笔刷的混色效果和当前图层的透明度有关，这意味着：
- 如果下面图层的颜色比较均匀，那么混色的效果和在同一图层中混色相近。
  - 如果下方图层的颜色不均匀，那么颜色会发生一些区别。
Shading on a separate layer, using 覆盖模式 mode. Use this only if you’re fairly sure you don’t need to adjust the layer below, or the colors may become a mess.

透明度问题

The Color Smudge Brush blends with transparency. What this means is that when you start a new, transparent layer and “paint” on this layer, you will nearly always get less than full opacity.

因此：

在颜色均匀的图层上面新建一个图层涂抹上色，一切都很正常。
但如果你在涂抹图层下面又画了点什么，下面的颜色就会干扰到涂抹的颜色。

解决办法其实很简单：

先把下面一层的颜色画好，然后再画上面一层
- 如果你只是要铺底色，那就在下面一层把底色铺完
- 如果是要画光影，先在背景层画出粗略的色块和调子，防止串色。
- 也可以利用继承不透明度来限定上面图层的可见区域。
对于最后一种方法来说，涂抹上色时最好使用和下面一层反差最大的颜色。例如，先在底层绘制最深的色调，然后在上面的图层用高亮色调涂抹上色 (下图左)。也可以反过来先在底层绘制最浅的色调，然后在上面的图层对阴影区域涂抹上色 (下图右)。

平滑混色

要画出比较柔和的颜色过渡，可以通过下列几种方式进行：

Color Rate as low as 10% for round brushes, higher with non fully opaque brush tips.
Or set the Smudge Rate as low as 10% instead.
也可以把前两种方式配合使用，多做试验以找到合适的数值。
Optional: turn on Rotation for smoother blending.
Optional: turn on Scatter for certain effects.
可选：启用大小和不透明度选项，看看它们能不能有所帮助。

在上面的例子中，上半部分是涂抹模式，下半部分是钝化模式。左边为不透明度 70%、涂抹长度 10%、颜色量 50% 的效果。右边为不透明度 70%、涂抹长度 50%、颜色量 10% 的效果。不难发现，单凭这些办法还不足以得到令人满意的平滑效果。我们还可以在这个基础上再引入一些技术：

把颜色的过渡色调先分成几段画出来。下图的例子中用了三段。如下图的上半部分所示。
I color picked each of these values with the Ctrl + shortcut, then used them in succession.

绘画风格：油画肌理

Krita 自带的大多数颜色涂抹笔刷预设都会画出厚重的油画肌理。这是通过使用涂抹模式实现的。它们的原理大致是：

在涂抹模式下涂抹长度和颜色量选项均使用较高的效果强度
- 对于一般圆形笔尖或者完全不透明的预制形状笔尖，两者的效果强度可设为 50% 左右。
- 对于密度较低的笔尖或者带有透明度的预制形状笔尖，两者的效果强度可设为 100% 。
按需添加大小、旋转、分散等效果。启用更多效果后，可适当加大涂抹长度和颜色量的效果强度来对颜色混合程度的提升进行补偿。

在上图的例子中，第一排：1) 默认效果；2) 密度 50%，涂抹长度 100%；3) 加上颜色量 100%；4) 加上大小映射到随机度，分散 60%。第二排：1) 默认效果；2) 旋转映射到随机度，涂抹长度 100%，颜色量 100%；3) 大小动态效果；4) 旋转映射到随机度，涂抹长度 100%，颜色量 100%。还有一种值得推荐的技巧是：先把前景色和背景色设成不同的颜色，然后选中”Foreground to Background (前景色到背景色)“ 渐变，在笔刷选项列表中把”渐变“选项映射到随机度。还有一种技巧是分别用两种颜色绘制 (下图右下角的例子)。

Here’s some final random stuff. With pixel brushes, you can get all sorts of frill designs by using elongated brushes and setting the dynamics to rotation. You won’t get that with Color Smudge Brushes. Instead, you’ll get something that looks more like… yarn. Which is cool too. Here, I just used oval brushes and Rotation ‣ Distance.

绘画风格：数字水彩

本例中介绍的所谓”数字水彩“是一种柔和、平滑的上色风格，和真正的水彩有所区别。这种风格主要通过钝化模式来实现，主要技巧如下：

Contrary to the Smearing mode, you may want to lower opacity for normal round brushes to get a smoother effect, to 70% for example.
调整笔尖的淡化数值。
在使用分散或者其他效果时，可以把涂抹长度和颜色量的效果强度按需调整，以得到不同的效果。下图第一排：1) 涂抹长度和颜色量同为 50%，不透明度 70%，渐变映射到随机度；2) 加上旋转映射到随机度；3) 加上大小映射到随机度，分散 60%。第二排：不同的预制形状笔刷，涂抹长度、颜色量、不透明度全部为 100%，大小和旋转映射到随机度。第三排：用椭圆笔刷制作的一些效果。

模糊混色技法

我们已经在前面提过，如果只靠颜色涂抹笔刷：

先画底色再涂抹，得到肌理比较明显的过渡。
预先画出几段过渡色调然后逐个混合。

但如果你想要更加平滑的效果，那么就直接通过高斯模糊滤镜来实现吧！在下面的例子中，上半部分为高斯模糊滤镜，半径 20px。下半部分为先建立选区，然后在右键菜单中点击”变形“，选中”羽化选区“，半径 20px，然后再应用高斯模糊滤镜，半径 60px。

到这里，这篇教程也就结束了。颜色涂抹笔刷引擎是一个功能强大，用法多变的引擎。希望你可以大胆地进行探索，用它画出效果丰富的作品！