Compatible with Clip Studio Paint Ver. 1.10.5
 Reference layer
Reference layers are a layer setting that allows you to fill and draw on other layers while only referring to a specific layer or layers.
The layers of the image above are as follows.
Say we want to fill the line art on the “Fill” layer with white. As you can see in the bottom image, the [Fill] tool is not as effective as it should be.
This is because the tool is referring to the background’s lines as well as the line art.
By setting the line art layer as a reference layer and setting the fill tool to only refer to reference layers, we can fill in the line art cleanly.
This is because the tool is now only referring to the “Line art” layer, which was set as a reference layer.
 How to set a reference layer
Method 1: Select the target layer, and select [Layer] menu > [Layer Settings] > [Set as Reference Layer].
Method 2: Select the target layer, click the [Layer] palette’s menu button, and select [Layer Settings] > [Set as Reference Layer].
Method 3: Select the target layer, and select [Set as Reference Layer] from the [Layer] palette thumbnail’s right click menu.
*Displaying a reference layer
Once set as a reference layer, the [Reference layer] icon will be displayed on the layer palette.
*Setting multiple layers as reference layers.
Select multiple layers and use any of the methods above to set them as reference layers.
*Setting folders as reference layers
Folders can also be set as reference layers using any of the methods above. Once set as a reference layer, the contents of the folder will be referenced.
*Disabling reference layer settings
Settings can be disabled by repeating the setting operation on a reference layer.
Fill using a reference layer
Using the fill tool, we will paint the following image.
①The image is separated into “Line art”, “Fill layer”, and “Background” layers, with the “Line art” layer set as a [Reference layer].
②“Refer other layers” is selected from the [Fill] tool.
③ Check that [Multiple referring] in the [Tool Property] palette is on, and choose [Reference layer]. (This is set to [All layers] by default.)
④The “Fill layer” is selected and filled.
Only the reference layer, i.e., the “Line art” layer will be used as reference. This makes it easier to balance the image values and colors, as the background can be displayed while painting.
In this way, reference layers are used in tandem with layer and tool settings.
TIPS: Setting multiple referring
The following image was painted while setting the [Fill] tool’s multiple referring to [All layers]. The character cannot be painted cleanly, as all images, from the line art to the background, are being referred to.
To avoid this, the [Fill] tool’s Multiple referring should be set to “Reference Layer”.
TIPS: Setting all line art as reference layers
In cases where line art is divided into multiple layers, it is better to set all of them as reference layers.
Layers can also be grouped in folders and set as reference layers in one go.
 Create a selection area using a reference layer
As with the [Fill] tool, the [Auto select] tool can also use multiple referring for reference layers.
To do so, select [Refer to all layers] from the [Auto select] tool, and set [Multiple referring] in [Tool Property] to [Reference layer].
The [Auto select] tool also has the [Selection for referred layers] sub tool, which is pre-set to refer to reference layers.
The selection area can be used for various purposes, such as pasting color patterns.
 Using reference layers with pens and brush tools
Reference layers can also be used with drawing tools such as the Pen and Brush. As an example, we will introduce how to paint with the [Airbrush] tool using a reference layer.
①Select the [Airbrush] tool’s [Soft] sub tool, and in the [Tool Property] palette, turn on [Do not exceed line of reference layer].
②The line art is set as a [Reference layer], and a color layer is prepared separately.
③The inside of the line art is painted with the air brush. While doing so, the painted colors will not overflow as long as the position of the [Center](i.e. the mouse cursor) doesn’t exceed the reference layer’s line art.
TIPS: Displaying a brush’s center point
To display the center point of a brush, set [File] menu > [Preferences] > [Cursor] > [Brush-type cursor] to “Brush size and Dot”.
Note: Drawing tools that can be set with [Do not exceed line of reference layer]: Pen, Pencil, Brush, Airbrush, Decoration, Eraser, Blend]
Other than a select few, many tools do not display the [Do not exceed line of reference layer] option in the [Tool Property] by default.
With those tools, click the [Tool property] palette’s [Sub Tool Detail palette] display icon, and set the option in [Sub Tool Detail] palette.
Turn the [Anti-overflow] > [Do not exceed line of reference layer] option on in the [Sub Tool Detail] palette.
TIPS: Display the [Do not exceed line of reference layer] option in the [Tool Property] palette.
By clicking and displaying the “eye” icon next to the [Sub Tool Detail] palette, items can be displayed in the [Tool Property] palette.
This can be useful for displaying only your frequently-used settings in the [Tool Property] palette.
 Layer structures when using reference layers
While reference layers are useful in many ways, they cannot be used properly unless layers are structured with reference layers in mind.
By drawing the main lines and details on separate layers, tone work and base coloring monochrome manga can be sped up, as the main lines can be used as a reference layer.
① Set the character’s main line art as a [Reference layer].
② Draw the character details(patterns) on another layer.
③ Reference the “Main line” layer, and add color.
If the main line art and patterns were drawn on the same layer, it would be impossible to specifically set the main lines as a reference layer.
As it is difficult to retrace your steps when drawing, it is a good habit to draw the main lines and other elements on separate layers.