I’ve never really found a solution to an issue that’s been plaguing me since I first experienced it in Photoshop CS, and now, five versions later, it’s still bugging me!
What is it?
Well, seemingly randomly, Photoshop decides that when I use the solid fill bucket, or the pencil tool to “paint” something within a marquee selection, it will either “feather” whatever I’m doing to the pixels outside of the marquee, or “anti-alias” the inside border pixels of the marquee.
Sometimes, I actually want this to occur, but it doesn’t regardless of what I do (and I end up using the eraser tool with a low opacity to recreate it)
and then sometimes, when I really don’t want it to occur, it does.
Here’s an example screenshot of what I’m talking about:
See how it’s randomly added pixels outside of the select?
(The selection was drawn with the poly marquee tool, with feather set to “0” – the green colour was added with the pencil tool, with
normal mode and opacity set to
100, and size set to
This MUST be a setting somewhere that I’ve totally missed, and it’s driving me barmey!
Please could you advise me on how to disable anti-aliasing in Photoshop?
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Firsly feathering and anti-aliasing have different meanings, though for small a feathering radius the results are similar. “Feathering” effectively means fading the selection boundary out slowly, and is slightly different to “anti-aliasing” which means using intermediate values to smooth out jagged edges.
You need to turn anti-aliasing off in addition to setting the feather to zero to get what you want, which is a sharp rigid boundary. There should be a checkbox in the tool palette, next to the feather radius box:
(screen shot is from a very old version of Photoshop!)
It’s worth noting the black and white “marching ants” selection border only ever shows the 50% threshold of the selection, and is therefor just a guide. If you save the selection to an alpha channel you can see the selection opacities of every pixel, and thus see your actual selection.
This isn’t really a bug; it’s just how Photoshop handles selections. Selections are alpha masks in Photoshop CS+, and they behave as such, so they can have pixels that are only 1/127th selected.
One way to workaround this is to make your selection and fire up Select > Refine Edge and throw the contrast all the way up to 100%. It’s not perfect, but it does a pretty good job.
Another way to get rid of feathering is to use the Image > Adjustments > Threshold.
You will have to merge the selection layer onto a layer that is filled with white. Then make the Threshold adjustment. This will give you a mask to remove the feathering.
Surprising, you’re quite correct and there seems to be no way of preventing it from happening, even with no feathering, no anti-aliasing and the tolerance set to zero you still get additional pixels.
You can invert the selection and delete most of the anti-aliasing but some still remains inside the selection.
I added the example below, the anti-aliasing is most pronounced at the points on the top – I screen shotted so you can see the selection area. This was done in CS5 using the paint bucket tool.
It seems that “feather” must also be unchecked in the settings of the selection tool you use to make the selection
Right Click Selection > Stroke 1 px.
Magic Wand > Adjust Tolerance > Fill Inside
In some cases you must make the path first and then follow those steps while making the stroke with the pencil.