The solution in this case would be to flip the values of the colormap, using the command: colormap(flipud(hot))

Grab the colormap and flip it upside down: f = figure; surf(peaks(50)) colormap(f, flipud(colormap(f))) colorbar

Use flipud on the colormap — [X,Y,Z] = sphere(50); Z = Z*20 + 290; figure surfc(X, Y, Z, 'EdgeColor','none') colormap(gray) colorbar axis('square') figure surfc(X, Y, Z, 'EdgeColor','none') colormap(flipud(gray)) % Flip The 'colormap' colorbar % hcb.Direction = 'reverse'; axis('square') .

why wont you just invert the colormap by flipping up-down (flipud)? For example:

cmap=flipud(colormap(gray));
colormap(cmap);

or in a more compact way:

imagesc(your_image);
colormap(flipud(gray))

The call to |colorbar| returns a handle. There's lots of options in there to set, and you'll find the one you wanted, too. h = colorbar; set( h, 'YDir', 'reverse' );

oldcmap = colormap; colormap( flipud(oldcmap) );

If you don't want to actually change the values of your data, you can simply fetch the colormap of the figure and invert it using flipud.

cmap = colormap(gcf);
colormap(gcf, flipud(cmap))

This will invert the colormap while leaving your original data untouched.

From the first hit on Google: colormap(flipud(colormap))

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Or else you could just invert the image itself before showing it rather than the colourmap. I'm assuming either your data goes from 0 - 1 or from 0 - 255 so instead of

imshow(I) or imagesc(I) or ... image(I)? you can go imshow(1 - I) or imshow(255 - I)

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otherwise you could create a custom colormap.