Easy Grayscale to Color Conversion Using Gradient Maps
0. Introduction
Starting with grayscale is a great way of ensuring focus on the key fundamentals of composition, anatomy and values, before shifting your attention to colors.
In this tutorial, I will be showing you how to make the most out of Clip Studio Paint’s gradient maps and will show you my step-by-step process of going from grayscale to the finalized color version of an illustration.
1.1. Accessing the Gradient Maps
To access gradient maps, right-click on a layer, then go to [New Correction Layer], and then click on [gradient map].
The gradient map palette will pop up and simultaneously a new gradient map layer will be created above the layer you right-clicked on.
There are already a few default gradient maps available and you can browse through their sets from the [Gradient set] section on the left of the [Gradient map] palette.
1.2. Applying a Gradient Map From Gradient Sets
To apply any of the available gradient maps, click on them and then click on the second icon at the bottom of the [Gradient set] section.
If you hover your mouse over the icon it says [Load to gradient bar].
1.3. Changing and Adding Colors in a Gradient Map
After selecting one of the nodes on the slider, we can change its color with three options.
In the [Color] section, choosing the [Main drawing color] option will change the node’s color to your main drawing color.
Similarly, choosing the [Sub drawing color] option will change the node’s color to your sub drawing color.
The [Specified color] option has two further options. Firstly, you can click on the color under the option to open the color settings and choose a color of your choice from the color wheel.
Secondly, you can also click on the color dropper icon to pick your colors.
1.4. Adjusting Color Transition Between Nodes With Mixing Rate Curve
By default, the transition in color between all the nodes is very smooth. However, you can customize these transitions using the [Mixing rate curve] section of the [Gradient map] palette.
It is not active by default so you need to tick the checkmark next to the section for the graph for it to become active.
The mixing rate curve adjusts how the color transitions between the selected node and the node to its right. Therefore, the node that is farthest to the right does not have a mixing rate curve.
Using this curve you can decide how sharp or smooth a transition between two nodes will be, and if one of the colors will be dominant over the other.
By experimenting with the curve graph you can explore some very interesting color variations within two colors.
1.5. Changing Positions of Slide Nodes
The most obvious way of changing node positions is to click on a node and drag it to the right or left.
You can also use the [Position] section to move a selected node more systematically by either entering a number between 0-100 or clicking on the arrow next to it to get the increase and decrease options.
You can jump to the other nodes by using the arrow keys below the slider. The third icon is for flipping the gradient and the last ison is for deleting a node.
You can also delete a node by clicking on it and dragging it away from the slider.
1.6. Maintaining Original Values by Using Color Mode
When the layer is set to [Normal] the colors added to the gradient bar correspond to the value section they are added to but they replace those values with their own hue and saturation.
To explain, the slider’s far left denotes the darkest area of the artwork and the far right denotes the brightest values.
When applying color, whichever color you apply to the far right would apply to the brightest values so if you applied dark blue to the far left node all the brightest values will become dark blue.
While this is useful for special effects, one would normally prefer to preserve the values of the original grayscale artwork when coloring.
For this, [Color] mode comes in handy because it allows the colors to influence the values without any drastic changes to the actual values.
So dark blue applied to the far right node may influence the brightest areas and give them a blue tint but the value will stay light.
1.7. Creating a Gradient Map Set and Saving Gradient Maps
To create a new gradient map set, click on the wrench icon next to the group names in the [Gradient set] section and then click on [Create new set].
In the opened dialog box, name the set and click OK.
To save a gradient map to a set, click on the fourth icon [Create new gradient] at the bottom of the [Gradient set] section. Then name the gradient and click OK.
Like this, you can create custom gradient sets for different characters and environments.
2.1. Application Method #1: Applying to Entire Canvas
Since gradient maps only influence the layers below them, your gradient map needs to be above all layers in order to influence the entire canvas.
You can do this by either creating the gradient map layer (as shown in Section 1.1) above all layers or dragging it to the top.
2.2. Application Method #2: Clipping to a Layer to Apply to a Specific Area
To apply the gradient map to a single layer you can clip it to that layer by dragging it above that layer then clicking on the first icon in the second row of the [Layer] palette.
2.3. Application Method #3: Using Layer Masks to Apply to a Specific Area
All gradient map layers come with a default layer mask in the form of a white rectangle next to the gradient map icon on the layer. After selecting the layer mask you can edit it.
The white area denotes the area on which the gradient map is active.
You can exclude areas from the gradient map’s influence using the transparent color. All other colors activate areas of the gradient map’s influence.
2.4. Application Method #4: Switching Default Layer Masks With Custom Layer Masks
Instead of working in the default layer masks that come with gradient map layers, we can also replace them with other custom layer masks.
I usually create layer masks from my grayscale or flat colors layers and apply them to the gradient maps.
There is a quick way and a slightly slower way to do this.
For the quick way, use the [Auto select] tool (with [Apply to connected pixels only] turned off) to select whichever base color you want to create a gradient map mask for. Then right-click on a layer, go to [New Correction Layer] and [Gradient map].
With this, a gradient map layer will be created with a custom mask where only the previously selected area is active.
The second, longer way, is as follows and also lets you know how to create and shift masks to other layers:
To create the mask go to the layer that contains the section you want to apply the gradient map to. Then using the [Auto select] tool and making sure [Apply to connected pixels only] setting is off, click in a transparent area. This selects all the areas not in use by the layer.
Then, right-clicking on the layer, go to [Layer Mask] and then [Mask Selection]. This will mask the transparent areas in the layer so only the color area is active and the mask will show next to your layer.
To apply the mask to the gradient map, drag and drop it onto the gradient map’s layer.
3.0. Practical Demonstration
This section will show how to apply the above information to an actual grayscale illustration to efficiently change it to color.
3.1. Layer Divisions Through Separate Base Colors
Once the grayscale version of the illustration is complete, we will create seperate base color layers for different sections of the illustration such as the skin, hair, and clothes etc. All these layers will be above the grayscale illustration layer.
Set the [Layer Mode] of the base color layers to [Color] before filling in any color. This will adjust the color to the values below instead of being opaque and will give you a decent estimate of how that grayscale section will look in color.
This is what a flat color looks like in [Normal] layer mode:
And this is what it looks like in [Color] mode:
Also overlapping flat colors do not hinder the results as long as they are in their own layers and the hierarchy of the layers is correct.
For example, the umbrella’s blue color is also covering the cherry blossoms that are to be pink. However, as long as the base color layer for the cherry blossoms is above the umbrella’s base color layer and is an opaque color, it will not be impacted by the colors below.
Due to this, we can save time by not needing to be precise with all our flats.
For example, in the below GIF, the base color for the hair extrudes the boundaries in many areas, but because the more precise base color layers of the umbrella, skin, and shirt are above it, this cannot be noticed in the results.
All these base color layers will later be used to create layer masks for the gradient maps.
3.2. Saturation and Desaturation in Coloring Skin
Using the process mentioned in Section 1.1, create a new gradient map layer. And with the help of Section 2.4 switch its default layer mask with a custom layer mask created from the base color layer of skin.
Switch the layer mode to [Color] and double-click the gradient map icon on the layer to open the [Gradient map] palette.
Depending on your illustration, you might need vibrant or muted skin tones so I will be demonstrating both.
When coloring skin, the hue slider plays an important role. As you go from light to dark areas, the hue slider moves from the yellows to reds. That is the case for both muted and vibrant skin tones.
For muted tones, as you travel from yellows to reds, you are also simultaneously going from whites to saturated grays. Try staying in this triangle:
Here is a demonstration of how I get muted skin tones:
For vibrant skin tones, as you travel from from yellows to reds, try to stay within this area:
Since we already have our values laid down, focus on hue and high saturation to get lively skin tones. Here is a demonstration of creating vibrant skin:
Switching the color of the far left node to more pure red can make the skin even more vibrant:
Tip: The more you bring out the corner nodes towards the center, the more that color will influence the highlights and core shadows.
3.3. Repeating the Process
For all the other major areas of your illustration you will likely be repeating these steps:
1. Creating the gradient map layer.
2. Creating a custom layer mask from your base color layer and inserting it in the gradient map layer.
3. Setting the layer mode to [Color].
4. Not sticking to just one hue throughout.
5. Having between three to five nodes preferably.
6. Saving your gradient maps for later use. Especially skin tone gradient maps.
7. For smaller details like lips and eyes, fill colors with a simple [Color] mode layer instead of through gradient maps to stay efficient.
(You can even bring base color layers of smaller details above the gradient map layer, and adjust the colors after locking the transparent pixels with the fifth icon in the second row of the [Layer] palette).
3.4. Using Saved Gradient Maps
If you use gradient maps often, you would soon have a library of gradient maps for different characters, outfits, hair and skin etc, so you only have to make the adjustments once and can use them over for as long as you like.
(You can save them using the process in Section 1.7 and apply them with the help of Section 1.2).
Here I have already created a gradient map for the brown hair so I only have to apply it:
3.5. Changing Colors
You can quickly change colors in any gradient map by adjusting the hue slider in a node’s color setting. You can also easily fine tune your choices by adjusting saturation.
You can also fine tune your hues and saturation by creating a hue/saturation/luminosity correction layer. To create this layer, right-click on a layer, go to [New Correction Layer] and then click on [Hue/Saturation/Luminosity] to open its sliders.
You can also use this corrections layer’s layer mask to target specific areas as you would with gradient maps.
Here are the final results:
4.0. Final Thoughts
This is it for the tutorial. I hope you liked it and if you have any questions feel free to let me know in the comments.
Gradient maps are an amazing tool that make coloring really fun, quick, and easy and allow you to experiment with the colors without affecting other areas of your art. I hope you will also find this to be true once you get the hang of them.
Thank you for reading!
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