The effect creation method in this tutorial is very clever. Mainly use brushes to create highlight parts. Define the brush first, and then set the parameters appropriately before use. The author used hidden layers for the coloring part. But you can also use gradient mapping.
final effect
1. Create a new document of appropriate size and select "Gray" to fill the background layer. Remember it is gray, not black. If you fill it with black, the effect will not be achieved. The gray I chose here is #262626.
2. Create a new layer 1, hide the background layer, use the Ellipse tool and hold down the SHIFT key to draw a black circle, set the fill transparency to 50%, then select the layer's blending options >> stroke, and set the color to Black, position: inside, size 3px, the effect is as follows:
3. Select: Edit>>Customize Brush, and define the circle we just drew as a brush.
4. Select: Window>>Brush, select the brush we just defined, and make the following settings:
5. Create a new layer, fill it with any color, and set the fill transparency to 0%, then select the layer's blending options>>Linear fill, set the blending mode to "Overlay", set the angle to "45 degrees", and select the style "Linear", you can arbitrarily define the gradient color you like, as shown below:
