Understanding
color ramp modes

In today’s tip we’re going to take a closer look at the good old color ramp node.

The color ramp node in (ramp setting in BI) lets you map an image or texture to a color gradient. The gradient is defined by 2 or more color stops. How the color in each stop transitions into the next is defined by the mode. The different modes give the ramp a lot of flexibility and power, though we don’t often talk about them.

Let’s check how the different modes work by checking them on a simple voronoi texture. Don’t worry, I won’t go into any of the math behind these because my brain melted from just looking at the equations. I’ll include the Wikipedia links below if you want to investigate further.

Linear

The default mode. Full stop color happens only in a small part and transitions quickly into the next. The middle point between two color stops has a 50/50 mix of both colors.

Useful when controlling a fresnel and trying to keep a thin, hard edge on the sides where the effect is the strongest.

Check Linear Equations in Wikipedia

Ease

This mode eases the ramp by a quadratic equation.

Transitions are smoother than linear since each stop’s influence is more spread out. That also means that you get more full stop color.

Ease is the mode I use the most, since the transitions are smoother than linear but not too much.

Quadratic Equation in Wikipedia

B-Spline

This is the smoothest mode. You never see full stop color here, instead colors flow into completely each other.

The B-spline mode is great to soften masks and textures. Keep in mind, however, that it can’t soften an image that has no intermediate values between colors (something crunched by the constant mode, for instance).

B-splines in Wikipedia

Cardinal

Cardinal gives a larger transition with more amount of full stop color.

I haven’t found many uses for cardinal so far, but if you find yourself looking for a softer ease ramp you should try this mode.

I couldn’t find the exact equation for this, but this post from Harder, better, faster, stronger might give you a hint.

Constant

Sometimes people try to crunch values by pushing them together in the ramp with the default value. But that’s not always the best option, the proper way is to use the constant mode.

This mode splits the ramp in absolute values at each stop. Not only you get the same effect with one click, but you can also move the stops to tweak the effect. Constant mode is basically like using the “Round” operation from the Math node, but more versatile.

There’s no particular equation in this mode. Each stop covers the ramp until the next without transitions.

That covers the current modes as for Blender 2.74. I Hope you’ve found this useful, stay tuned for more tips!

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