Color Assistant

Color Assistant is a floating palette you can keep beside your canvas. Pick on its wheel and the color goes to your painting app's foreground color—the color your brush currently uses. In apps with two-way sync, changing color with the app's own wheel or eyedropper updates the floating palette too.

To sample one color from a reference anywhere on screen, use the palette's eyedropper or open the Color Picker directly.

Feature walkthrough: the color wheel, gamut mask, and three value-check modes. The video text is in Chinese.

Info

Picking colors, managing palettes, and checking values happen locally and use no Nepheline.

Try it

Open your painting app and a canvas. Choose Color Assistant in Nephele's toolbox, or press Ctrl + Shift + C. You can change the shortcut under Settings → Hotkeys; press it again to hide the palette.
Drag on the wheel to choose a color and use the vertical slider to adjust lightness. The palette shows the current color and connection status.
Continue painting. If the app is not connected, use Copy to put a HEX color code (such as #4A78B2) on your clipboard.

The palette remembers its position and size. You can also double-tap Ctrl and launch it from the Astrolabe.

Wheel, palettes, and history

Move around the wheel to change the color, outward to make it more vivid, and along the right-hand slider to make it lighter or darker. The wheel uses OKHSL; the separate Color theory article explains how it differs from an ordinary HSV wheel.

Below the wheel are foreground and background swatches. Click the background swatch to swap them; the foreground color is the one sent to your painting app. History keeps recent colors ready to reuse.

For a palette based on a reference, use Extract Palette on an image in the Reference Board. The extracted colors appear as a named palette at the bottom of Color Assistant. Switch between History and Palette, pick a swatch, or switch and remove saved palettes.

The Gamut Mask button in the title bar overlays a suggested color range on the wheel. Change its shape, rotate it, and choose Generate Palette to save a set of colors. The mask is a guide: you can still pick anywhere on the wheel. The Color theory article explains the five shapes and how the palette is generated.

Painting app connection

The status line at the bottom of the palette shows which painting app is connected. Once connected, color moves in both directions:

From Color Assistant to your brush: pick on the floating wheel and the painting app's foreground color changes. You can continue painting with it immediately.
From your brush to Color Assistant: choose a color with the painting app's wheel, eyedropper, or color panel, and the floating wheel moves to that color.

Recorded demo of two-way foreground-color sync in 优动漫, CLIP Studio Paint, Photoshop, and PaintTool SAI 2. The video UI is in Chinese.

CLIP Studio Paint (international) may ask you to pair Companion Mode and restart CSP on first use. Follow the prompt in the palette. Once connected, both directions work. If the connection is temporarily unavailable, Color Assistant tries to send your picked color through CSP's on-screen eyedropper; color changes made inside CSP will not return to the palette until the connection recovers.

优动漫 PAINT PRO / EX, PaintTool SAI 2, and Photoshop do not use CSP's pairing process. With the painting app open, picking on Color Assistant changes its brush color; changing color inside the app updates Color Assistant. For example, choose blue from Photoshop's foreground swatch and the floating wheel moves to that blue.

If the status line says the app is not connected, check that the painting app and a canvas are open. You can still use the wheel and screen eyedropper with other apps: choose Copy and paste the HEX value into the app's color field.

Versions checked

The following versions had compatibility checks as of September 2026. They do not imply that every version between two dates or numbers is supported. An app update—or a different build with the same version number—can change how the color link behaves.

CLIP Studio Paint (international): the demo uses Ver. 5.0.0. Two-way sync requires CSP's Companion Mode to open and pair successfully. Other versions have not been checked one by one.
优动漫 PAINT PRO / EX: builds labeled 4.0.5.0 have been checked. PRO and EX are separate executables, and different builds can share the 4.0.5.0 label; the number alone cannot guarantee that color changes read back correctly.
PaintTool SAI 2: two-way operation was tested hands-on in Preview.2024.05.22, Preview.2024.08.14, and Preview.2026.07.02b.
Photoshop: two-way operation was tested in 2021 (22.3) and 2022 (23.0). Other yearly versions have not been checked one by one.

For an unlisted version, try both directions: pick in Color Assistant and watch the painting app's foreground swatch, then change color in the painting app and watch the floating wheel. If only one direction works, use it as a one-way link or copy the HEX value. When reporting a compatibility issue, include the app name, full version, and the PRO / EX edition or SAI 2 Preview date where relevant.

Check your values

Use Value Check in the title bar to view the whole screen in grayscale, including your canvas and references. Press it again to restore color. This changes the display temporarily; it does not edit your artwork.

Choose Standard, Desaturate, or Perceptual under Settings → Luminance Algorithm. The Color theory article compares their output with actual color values. The Reference Board uses the same setting for its grayscale view.

Color Picker: sample a single pixel anywhere on screen and copy its HEX value.
Reference Board: keep reference images beside the canvas and extract a palette from an image.
Color theory: understand OKHSL, gamut masks, and the grayscale algorithms in depth.
Glossary: look up terms used in the guides.