Hi Stefan, Works perfectly. However, I'm not sure why but I had to initialize the jet colormap object to create the _lut array. I replaced: lut = plt.cm.jet._lut[..., :3] By: jet = plt.cm.jet jet._init() lut = jet._lut[..., :3] Thanks a lot. Guillaume On Nov 25, 2012, at 8:25 PM, Stéfan van der Walt <stefan@sun.ac.za> wrote:

Hi Guillaume

On Thu, Nov 22, 2012 at 8:08 PM, Guillaume CALMETTES <guillaume.calmettes@gmail.com> wrote:

...

Do someone has any trick to convert a "jet image" to grayscale?

Here's a snippet that does it by brute force lookup:

https://gist.github.com/4146612

Hope that helps! Stéfan

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