What is the default ColorFunction for Image3D?

Question

What is the default ColorFunction for Image3D? I find it a bit confusing that the most intense colour is not shown where the highest values appear:

data = Table[
   Exp[-3 (x^2 + y^2 + z^2)], {x, -1., 1, .01}, {y, -1., 
    1, .01}, {z, -1., 1, .01}];

Image3D[data, ClipRange -> {{100, 200}, {0, 200}, {100, 200}}, 
 ColorFunction -> Automatic] (* default colour function *)

enter image description here

Note that the bright yellow is not in the middle of the sphere. I wanted to understand what causes this effect (possibly some interplay of opacity and colours?). Otherwise I like the default. Did anyone try to reconstruct the default ColorFunction for Image3D?

score 18 · Accepted Answer · answered Dec 05 '13 at 22:55

18

According to the documentation of Image3D, "an interactive color function editor is available via the Image3D contextual (right-click) menu". (And yes! I only found it after reading your question!)

contextual menu

ColorFunction editor

And you can get the explicit function by clicking the "Copy Function" button.

Blend[{
       {0., RGBColor[0.05635, 0.081, 0.07687, 0.00343663]},
       {0.1, RGBColor[0.8877, 0.2636, 0., 0.103093]},
       {0.3, RGBColor[1., 0.6036, 0., 0.302406]},
       {0.66, RGBColor[1., 0.9658, 0.4926, 0.661168]},
       {1., RGBColor[1., 0.6436, 0.03622, 1.]}
      }, #1] &

answered Dec 05 '13 at 22:55

Silvia

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I feel stupid now. I never noticed that! – Szabolcs Dec 05 '13 at 23:10
1

@Szabolcs I doubt anyone noticed :) – Silvia Dec 05 '13 at 23:23
I didn't know that! A new world of possibilities... _ – Ziofil Apr 07 '14 at 20:50
That looks awfully like Wolfram's version of MATLAB's hot() colormap… – J. M.'s missing motivation May 06 '15 at 10:58
@J. M. Woww! Long time no see! Welcome back! :DD – Silvia May 07 '15 at 01:33
Somewhat back, yes. Thanks @Silvia! – J. M.'s missing motivation May 07 '15 at 02:16
@Silvia What is your system? I am having memory problems with the code in Mathematica 11 of Debian 8.5, thread here http://unix.stackexchange.com/q/311921/16920 – Léo Léopold Hertz 준영 Sep 23 '16 at 18:20
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@Masi If my memory is correct, it was Windows 8 64bit. Regarding your problem, I think you might get more help from the WRI company. They are more expert than any users and they might already have some solutions. – Silvia Sep 25 '16 at 10:08
@Silvia Do you mean by WRI company the Wolfram Support? - - I already contacted them about the problem - now, waiting for their answer. – Léo Léopold Hertz 준영 Sep 25 '16 at 12:50
1

@Masi Sorry for the acronym. Yes WRI = Wolfram Research, Inc. I think their support is your best chance for solving the problem. – Silvia Sep 25 '16 at 18:10

What is the default ColorFunction for Image3D?

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