splitting hue & saturating and leaving value behind
Removing hue and saturation (&quot;desaturating&quot;) leads to a grayscale image with the same luminance as the original colors, for instance:


(source: my own photo)
It is not possible to remove hue alone without removing saturation, as any saturated color must be saturated in some direction (hue). Nor is it possible to &quot;split&quot; the image into HSV &quot;components&quot; in quite the way you can split into RGB components. Hue works like an angle of rotation around the &quot;color wheel&quot;, while saturation is the radius from the center:

(image from here)