颜色和影调的过渡

颜色在亮部和暗部怎样变化，过渡是否连贯，比颜色本身更能说明一张照片。

两张照片可以有几乎一样的平均颜色，看起来却完全不同。差别常常在于颜色怎样随亮度变化，以及从一个影调到下一个影调的过渡是否连贯。

颜色不是一个固定值

在胶片上，颜色的饱和度和色相会随曝光变化。很多彩色负片在中间调颜色最饱满，到亮部和暗部逐渐收敛，阴影还可能带一点偏色。这种变化让照片有层次：亮处轻，暗处沉，中间最“有颜色”。

数码照片的颜色由传感器和相机配置文件决定。配置文件通常追求准确和一致，有时会在某些色相上做强调，比如让蓝天更蓝。后期里把某个 HSL 滑块推到很远，也会让一种颜色在所有亮度上都同样浓，失去随光线变化的感觉。

过渡是否连贯

看一片天空从地平线到头顶，看一张脸从受光面到背光面。连贯的过渡没有台阶、没有突然的色相跳变。过渡出问题的常见原因：

8 位 JPEG 上做大幅调整，渐变处出现色带（banding）。
局部调整的边缘太硬，留下一圈光晕。
同时把对比度和饱和度拉高，暗部的颜色挤在一起，变成一片。
强烈的降噪把细微的颜色变化一起抹掉。

可以试的做法

在 RAW 上调色，并尽量用小幅度调整完成。
用曲线分别轻微调整亮部和暗部的颜色，而不是整张照片统一偏色。
检查皮肤：脸上从亮到暗的颜色应该是一条连续的变化，不应出现发灰或发橙的一块。
放大到 100% 看渐变区域，再缩小到手机大小看整体。两种尺寸都没问题，才算过关。

FilmLook 的色彩读数和色彩分布图描述的是成片本身，包括拍摄场景的颜色。一张满是绿树的照片会偏绿，这说明的是场景，不一定是胶片或后期的特征。

下一篇：摄影师怎样形成可辨认的风格

上传一张照片试试

All guides

Colour response and tonal transitions

How colour changes between shadows and highlights, and whether transitions hold together, says more than the colours themselves.

Two photos can have almost the same average colour and look entirely different. The difference often lies in how colour changes with brightness, and in whether the transition from one tone to the next holds together.

Colour is not a fixed value

On film, saturation and hue shift with exposure. Many colour negative films are most saturated in the midtones and quieter towards the highlights and shadows, and the shadows may carry a slight cast. That variation gives a picture depth: light areas feel light, dark areas heavy, and the middle carries the colour.

In a digital photo, colour is set by the sensor and the camera profile. Profiles usually aim for accuracy and consistency, sometimes emphasising certain hues, a bluer sky for instance. Pushing an HSL slider a long way in editing also makes one colour equally strong at every brightness, which loses the sense of colour changing with the light.

Do the transitions hold together?

Look at a sky from the horizon to overhead, or a face from its lit side to its shadow side. A coherent transition has no steps and no sudden jumps in hue. Common causes of trouble:

Heavy adjustments to an 8-bit JPEG, which leave bands in gradients.
Local adjustments with hard edges, which leave a halo.
Contrast and saturation raised together, so colours in the shadows bunch into one mass.
Strong noise reduction, which wipes out fine changes of colour along with the noise.

Things to try

Grade from raw, and reach the result with small adjustments.
Use curves to adjust the colour of the highlights and shadows separately and lightly, rather than tinting the whole picture.
Check skin: the colour across a face from light to dark should change continuously, with no grey or orange patch.
Look at gradients at 100%, then at phone size. It works only if both look right.

FilmLook's colour readings and colour scope describe the finished photo, scene included. A photo full of green trees will lean green; that says something about the scene, not necessarily about film or editing.

Next: How photographers develop a recognisable visual style

Try it with a photo