Colour Grading Using Curves and Levels For Anime Style Background Art


In this quick tutorial, I will be showing you some basic information on colour grading. The result image which later can be use for paint over into an anime style background.

What Is Colour Grading?

Color grading is the process of improving the appearance of an image through the use of different colour adjustment tools such as curves, levels, photo filter and etc.

Colour Grading and Anime Style

Anime background arts are usually more vibrance and saturate. Sometime, adjusting saturation or vibrance on an image is not enough as we want to achieve a different style on the photo.

shadow colour
For example, shadows in a lot of anime background arts are more blue so we will want to boost cyan or blue colour in the shadow.

More info on What is shadow colour?


Shadows, Midtones, and Highlights

Highlights are the brightest area in an image as that receive the most light while shadows are the darkest area. Midtones are the area in between highlights and shadows. It is important to know how to adjust these areas through the use of curves or levels tool, so lets look at the image below.

Curves and Levels tool
By dragging the little arrow on the specific area, we will be able to adjust the image tonality. You might notice there are options like Output and Input as well.

Curves and Levels tool
We will be using this photo and the colour ramp as an example to get an better understanding how adjusting Input and Output affect an image.

Adjusting the Input

First we will experiment by adjusting the Input option. Pay close attention to the colour ramp.

Adjust Input Shadows
Adjusting the Shadows Input will darken all the pixels in shadows area. In photography and colour grading for film, people usually call this "crush the blacks".

Adjust Input Highlights
Adjusting the Highlights Input will brighten all the pixels in highlights area. Making the photo overexpose.

Adjust Input Midtones
Pulling the Midtones arrow to the left reduce contrast, making the overall photo brighther.

Adjust Input Midtones
Pulling the Midtones arrow to the right increase contrast, making the overall photo darker.

Adjusting the Output

Lets experiment adjusting the Output option now. Again, pay close attention to the colour ramp.

Adjust Output Shadows
Adjusting the Shadows Output will clip away the darkest value.

Adjust Output Highlights
Adjusting the Highlights Output will clip away the brighthest value.

There is no option to adjust the Output Midtones using Levels tool as we can't really clip away value between brighthest and darkest pixel. Adjusting the Output Midtones in Curves tool are actually just same with adjusting the Midtones Input.

Adjust Output Midtones
Pulling the Midtones arrow down is same with pulling the Midtone arrow to the right, which increase contrast.

Adjust Output Midtones
Pulling the Midtones arrow up is same with pulling the Midtone arrow to the left, which reduce contrast.

Colour channel

The examples above are just showing basic adjustment on all RGB channel as a whole. With Curves and Levels tool, we can also go into individual RGB channel for adjustment. This is how we boost or reduce certain colours in an image.

Opposite Colour
When we are adjusting the individual channel, we have to understand that each RGB colour has an opposite CMY colour.
  • Red opposite colour is Cyan
  • Green opposite colour is Magenta
  • Blue opposite colour is Yellow

For example, we are able to adjust both blue and yellow colour in Blue Channel. If we increase the intensity of blue in Shadows, the image will be more blue in Shadows. But if we reduce the intensity of blue colour in Shadows, the Shadows in our image will be more intense in the opposite colour which is yellow. Sound confusing? Don't worry. Lets look at the image below.

Opposite Colour
In the image above, we can see RGB colour and their opposite CMY colour in Curves tool. Moving Shadows, Midtones or Highlights into the colour zone will increase intensity of the colour. For example, to increase blue in Shadows, we move the Shadows arrow into the blue zone under Blue Channel.

Blue Channel Colour Adjustment
Image above showing various adjustment on Shadows and Highlights under Blue Channel, resulting in a more blue or yellow tint image depending on the Curves settings.

Blue Channel Colour Adjustment
And this image I had increase blue in Shadows and yellow in highlights.

Curves and Levels Tool Cheat Sheet

I won't be able to go through all the RGB channel, so please use the image below as a reference or guide.

Adjusting Curves Input
Adjusting Shadows and Highlights Input using Curves.

Adjusting Curves Output
Adjusting Shadows and Highlights Output using Curves.

Adjusting Levels Input
Adjusting Shadows and Highlights Input using Levels.

Adjusting Levels Output
Adjusting Shadows and Highlights Output using Levels.

Difference between Curves and Levels Tool

You might be wondering what is the differences between Curves and Levels tool if both can produce the same result. One of the main different is we have more direct and easier control in using Curves such as producing the colour below.

Colour Curves Adjustment Example
Increase blue in Shadows and increase yellow in Highlights while keeping the darkest Shadows as black and brigthest Highlights as white.

Colour Curves Adjustment Extreme Example
Extreme example of colour adjustment using Curves on all RGB channel.

Using Multiple Colour Adjustments and Layer Blending Modes

it is possible to use multiple Curves, Levels or any other Colour Adjustment tools in a single photo. Sometime, changing the layer opacity and blending mode will also give some interesting result.

Layer Blending Mode on Colour Curves
Image above show how different layer blending mode on Curves adjustment affect the final result.

Layer Opacity on Colour Curves
To quickly reduce the intensity of colour adjustment, we can reduce the opacity or fill on the Curves adjustment layer.

Example

Now we have go through the basics of Curves and Levels tool. It is time to apply what we had learn so far into some real example.

Layer Curves Adjustment Tutorial
In this example, I am using a photo of the same location but in night settings. I will be adding more cold colours in Shadows while adding more warm colours in the Highlights.

Layer Curves Adjustment Tutorial
Step 1. Add a Curves adjustment and goes to Blue channel to add in some blue colour for Shadows.

Layer Curves Adjustment Tutorial
Step 2. To make the Shadows more closer to cyan colour, goes to Green channel and add in some green colour for Shadows,

Layer Curves Adjustment Tutorial
Step 3. Goes to Red Channel, and add in red colour for the Highlights.

Layer Curves Adjustment Tutorial
Step 4. Set Curves adjustment layer blending mode to Color.

Layer Curves Adjustment Tutorial
Step 5. Add a Vibrance adjustment layer and increase the vibrance. Adjust opacity of vibrance to 50 percent.

Video

A timelapse video showing the process of painting over photo into anime style background art.



Final Word

Different photos require different settings to achieve different results. But the example above where I show boosting cold colour in the Shadows should be useful in a lot of cases for your painting. I will share more curves settings whenever I find some free time! Thanks!

Reference

DeviantArt Shop Night Scene
Pixiv Shop Night Sceneh
Youtube Photoshop Anime Style Street Shop Night Scene

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