I am trying to create a 3d icon / logo. For some reason I get some pixelation / jagged lines on some of the edges. If you look at this you will see the top and bottom of the screen isn't looking very nice.
Generally, higher contrast edges can be more difficult to smooth. If you make the screen white and the device's face black you'll see this.
Some filters might help, like combinations of outer or inner glow.
I think the simplest trick is to paste into Photoshop as a Smart Object at 144ppi - If the icon is going to be 128px, the PS file should be 256px at 144ppi.
I like to create an additional layer above the default background layer called BLANK, this makes it easier to use Layer > Merge Visible.
Turn off or delete the default background, unless you need to test against various background colors.
Select any of your visible layers and Layer > Merge Visible.
Than Image > Image Size, set the Resolution to 72ppi, and set the Resampling to Bicubic/Smooth, Bicubic/Sharper will often create a halo around edges that becomes problematic when working at the small scale of an icon.
It's essential to resample to exactly 50% for the best result.
The last step is the trick. It's great for finalizing images for web. You can do a direct comparison - Prepare two 128x128 Photoshop files, in one you either paste as a smart object or as a raster, in the other you paste a rasterized version resampled and scaled. Save each for web as PNG256 or GIF256 and you'll see that the resampled icon has more colors (presuming that you're not maxed out at 256), and on a side by side comparison is of noticeably better quality.
This isn't always the best process for icons, but it's usually the best process for icons, at least until you get down to the 16x version where you may also need the pencil tool.
Just a bunch of random thoughts about icons :)
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