Selecting every other pixel in an image?

[Scantredle]

I've recently started working with a specific concept that I really like and I just want to know if there is any tool or method for doing something that is otherwise very time consuming. What I'm trying to do is select every other pixel in an image so I can invert them. I've been doing it manually by selecting every other pixel in a small area and moving that selection shape around until I have finished inverting every other pixel. So none of the selected pixels are immediately bordering each other, and they only touch diagonally. I know I'm probably asking for a lot but I'm hopeful that there is some way of doing this faster.

[Red ochre]

Scintillate  Any use?

[MJW]

If you want to invert every other pixels, this should work, I think.

Add a layer.

Use BoltBait's Grid/Checkerboard plugin to create a 1-pixel-width checkerboard pattern.

Set the Blending Mode to Difference.

Merge the layers.

 

If you really need to select every other pixel:

Create the checkerboard in a new layer.

Select the Magic Wand tool.

Set the Flood Mode to Global.

Select a pixel.

Switch to the layer you want to use it on.

 

 

[Red ochre]

9 minutes ago, MJW said:

If you want to invert every other pixels, this should work, I think.

Add a layer.

Use BoltBait's Grid/Checkerboard plugin to create a 1-pixel-width checkerboard pattern.

Set the Blending Mode to Difference.

Merge the layers.

 

If you really need to select every other pixel:

Create the checkerboard in a new layer.

Select the Magic Wand tool.

Set the Flood Mode to Global.

Select a pixel.

Switch to the layer you want to use it on.

But why?

[MJW]

1 hour ago, Red ochre said:

But why?

 

The Difference blend mode will, I believe, invert the color of all the pixels that are blended with white and leave the pixels blended with black unaltered. I think Negation would also work.

 

Or do I misunderstand what you're asking Why about?

[Red ochre]

But 'Scintillate' does this in one operation either diagonally or as a lattice. Unless I have completely misunderstood the question - which is quite possible!😉

Why use scissors when you can strap two pieces of flint together with deer sinew?... no bad feeling intended, I'm just perplexed as to the advantages of your method?
Oh well...I'm sure there is a reason.

 

No rudeness intended.

[MJW]

Well, actually I didn't really know what Scintillate does, and your comment "Scintillate  Any use?" didn't suggest to me it did exactly what was being asked for. I suppose the comment may have been intended as a sort of understatement. In any event, the method I suggested (while more complex than using Scintillate) is pretty trivial; especially if someone already has BoltBait's plugin pack installed. My comment also answers the original question of how to select every other pixel, which could possibly be useful in itself.

[Scantredle]

Damn, I wish I could tag 2 suggestions as the solution. I tried the ideas from MJW and Red ochre. Both solutions worked exactly how I wished they would, but I will say that the Scintillate was much quicker and easier. Thank you both for your wonderful suggestions! I wasn't expecting such good answers so quickly!

[AndrewDavid]

EER & TR - no-one has noticed my deliberate mistake in the code yet? 

@Red ochre

Too late to mention it now. 9 year old thread.

 

[Rick Brewster]

You can also just create a new layer, fill it with the 50% pattern via Paint Bucket, switch to Paint Bucket and use Global flood mode and a Tolerance of 0, and click on one of the pixels. Then, use Edit -> Copy Selection, delete the layer, and then Edit -> Paste Selection -> Replace on the original layer. Voila. No plugins needed.

 

Be forewarned, once you click with the Magic Wand, this will be slow and use a lot of memory if the image is large.

 

Also don't do this if you're prone to seizures, the selection will be flashy and weird looking, but it's doing the correct thing.