To create a seamless pattern open the desired image and choose Filter > Other > Offset
Increase the values so that you will be able to easily see the offset and for Undefined area, choose Wrap Around.
Use the Healing Brush or clone stamp tools to remove any noticeable seams – being careful next to the borders of the image (if you change the border areas, it might not tile seamlessly).
To verify that the pattern will be seamless, run the filter again – this time you shouldn’t see any seams. If you do, use the Healing brush to remove them and run the filter again.
Once the file is seamless, choose Select > Select All and then Edit > Define Pattern. Give the pattern a notable name and click OK. This pattern will now be available when using Edit > Fill, Layer Styles, Pattern Fill Layers, the Pattern Stamp, Healing Brush, Shape Tools (for both Fill and Stroke) and when creating Brushes (using the Texture attribute).
by Julieanne Kost
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