How to create a customized color cycle picture?

Question

It is part of a university project visualize displacement of speckles between to pictures. To do that I use the HSV color room, so the angle of displacement is respresented by hue and the displacement represented by value. The saturation is always 100%.

What I need now is a picture with a 2 dimensional color cycle which is dark (black) in the middle and full colorized at outer edge of the cycle. This picture will be implemented in the software to simply explain the visualization of the Speckle.

I have photoshop but solutions with another software are accepted.

How to create such a color cycle?

Answer 1

With Gimp:

• Step 1 with Blend tool:

  • Mode: Normal (default)
  • Gradient: Full saturation spectrum CW
  • Shape: Conical (asym)

  Drag horizontally from center.

• Step 2 with Blend tool too:

  • Mode: Multiply
  • Gradient: FG to BG (RGB) (this assumes your foreground color is still the default Black, and the background still the default White)
  • Shape: Radial

  Drag from center (direction unimportant)

I assume the Photoshop procedure won't be very different (gradients and shape can have other names). For best accuracy create guides that cross on the center.