Wish list: color interpolation

Jun 9, 2009 at 4:20 AM

It would be great to have the option of interpolating between two colors by hue, rather than (on a poorly informed guess at your algorithm) by interpolating RGB values.

When I try interpolations between two colors using the Autofill Columns dialog, I essentially get two pure colors at either end, going through a muddy mix in the middle.  Perhaps the best has been between cyan and magenta, which goes through a muddy blue.  The saturation definitely changes, though.

My dream would be to be able to vary Hue, while keeping Saturation and Value constant (H, S, V).  That way it should be relatively straightforward to create "rainbow" color interpolations. And once that option is available, one could vary any of (H, S, V), e.g. keeping the hue and value constant but just changing the saturation.

Thanks for a great tool!

--- Pierre

Jun 10, 2009 at 1:10 AM


Is it possible to create a gradient between two arbitrary colors without sometimes getting a muddy mix in the middle?  I suspect not.

I'm not sure how the interpolation is being done, because NodeXL relies on system-supplied drawing code for the gradient and its algorithm isn't documented.  It's not doing a simple interpolation between RGB values; instead it's probably converting to one of the alternative color models and interpolating there.

I compared what NodeXL does with what Photoshop CS4 does and they look exactly the same, which leads me to believe that NodeXL is probably doing the sensible thing with respect to color gradients.

-- Tony