how to make concentric circles

[mscallisto]

I wish to know the best way to make a series of concentric circles equal size and distance.

I've tried the following but need a better method.

The initial outer circle fills a 400x400 pixel screen and was made with the shift key and the ellipticle marquee then filled with black.

I tried using a series of select/modify/contract by 3 pixels where I could hopefully delete the differences and create my concentrics.
Thought this would be a good idea but can't make it work.

 

[WizyWyg]

If you are using the circle select marquee, on the tool information bar (PS 6 +) you can define a fixed size

 

[mscallisto]

I should have noted I'm still on 5.0

 

[WizyWyg]

erwww. ouch....

Time to upgrade.

 

[Nohjekim]

The easiest way to make concentric circles that I know of is just to draw them.

Drag in guides to form a square of the size that equals the diameter of the circle you want. Let's say 6"

Select the circle selection tool and drag from one corner to the other.

This will give you your first circle; fill it how ever you want.

Now move you guides to 4" Or one inch in from each side.

Draw circle number two, you can either fill it or hit delete to put in the background color.

Now move the guides in another 1" all the way around and you have a 2" circle.

Fill it and you have a roundel for a Spitfire wing.

This takes less time to do then it does to explain.

Mike

 

[blueark]

I don't think there's anything wrong with your idea in principle. However, contracting selections isn't very accurate. With that in mind, here's one way of correcting your method (I'm assuming from your post that you're trying to create black circles in a sort of op-art kind of way)

1. Make your document slightly larger than the 400x400 pixels, say 410x410, with a white background.

2. Open the Info palette (Window > Info)

3. Keeping an eye on the measurements in the info palette, create a circular marque 400x400 pixels and fill with black. Keep it away from the edges of the document as this can cause inaccuracies. Start around 5 pixels in (you can always crop it later)

4. WITHOUT DESELECTING, open the actions palette and create a new action (it may help to assign a shortcut key to this action). Contract your selection by 3 pixels and invert (Image > Adjust > Invert). Stop the action.

5. Again, without deselecting, play this action over and over (this is why it helps to create a shortcut key!)

As you can see, the circles loose their shape a little, but it's still a nice effect!