Bars or Stripes in gradient

Question

My slides use a subtle gradient on the background. I noticed, however, in Keynote 6.1 all my gradients are no longer smooth with gradual transitions. Instead, I see bars, as illustrated by the attached example. The bars exist in horizontal, vertical, or radial gradients. The effect gets worse with scaling (e.g. if I view a the presentation on a projector that scales down to 640x480, gradients are unusable across more than about 25 pixels). Any advice? Anyone else seeing this?

Answer 1

Thanks, Gary - I can understand certainly that lower resolutions might have some banding, but I am also on a 2560 x 1440 cinema display, and have never seen banding under the update like I do now on my own screen. Keynote used to do the gradients in a way that seemed to blur the transition such that even in lower resolution displays, I never saw the banding as long as the color depth was sufficient. If you cranked up the contrast, you could see the diffusion of bits between the colors as opposed to straight lines. Only on some older 8-bit projectors about the size of a VW was it ever a real problem, but never on anything made since the 80's.
The slide size in the "new" Keynote is under the Setup gear icon then in the Slide Size pane. I've tried various sizes from 640x480 to 2560 x 1440 and nothing helps.
So to me, it seems like the algorithm for the gradient changed. I actually tried making a gradient between the same two colors in Pixelmator, and it is smooth and even. I even pasted the Pixelmator image into a Keynote slide, make a PDF and it is still smooth and even - no bands or bars.
You can see the difference in the example image I attached. I made the Pixelmator gradient at an angle so you can see left/right easily and see the mid-tone.