Change the Brush Preview Color in Photoshop
If the default red brush preview is hard to see or distracting, you can change it to another color. Photoshop lets you set the Brush Preview color in the Cursors preferences. You’ll confirm the change by using the on-canvas brush resize preview.

Step-by-step instructions
1
Display the current brush preview (optional)
Select the Brush Tool (B).
Hold Alt and right-click, then drag to show the on-canvas brush preview color.
2
Open the Cursors preferences
Go to Edit → Preferences → Cursors.
3
Change the Brush Preview color
In the Cursors panel, locate the Brush Preview color setting and click the color box.
Choose a new color (e.g., blue) in the Color Picker.
Click OK to confirm the color, then click OK to close Preferences.
4
Verify the new preview color
Hold Alt and right-click, then drag again to see the brush preview in the new color.
Adjust size (left/right) and softness (up/down) as desired.