Teach me about unsharp mask on photoshop

When using unsharp mask on photoshop, what does the radius, and the threshold sliders mean?

Try my article here: Understanding Unsharp Mask

HTH.

Pretty sure the PS help file has quite a lot of useful stuff in it about USM...

Damo77 wrote in post #9575317
Try my article here: Understanding Unsharp Mask

HTH.

There is a lot of good stuff on your site Damien and way you explain it makes it easy to understand.

here is something that I have pinned by my computer..

https://photography-on-the.net/forum/showthre​ad.php?t=473056

thanks

canonnoob wrote in post #9576037
here is something that I have pinned by my computer..

https://photography-on-the.net/forum/showthre​ad.php?t=473056

That is a helpful chart -- thanks for reminding us and thanks to Stuart for putting it together and sharing (and to Scott Kelby for the original tips)!

Thanks also to the producers and the director for making all this possible and especially to Mom for popping me out, as embarassing as it must have been for her...

I came across this simple explanation a few weeks ago:

The 3 sliders are named Amount, Radius and Threshold.

Amount: Essentially a volume control.
Radius: Radius determines the number of pixels either side of the edge that will be affected during sharpening.
Threshold: Threshold determines how great the tonal difference between neighbouring pixels needs to be before they are assumed to be an edge.

As a General rule, set threshold to 1 or 2. radius between 1 and 3 pixels (the larger the pixel count, the higher the number) and gradually dial in the amount while zooming in and out to judge the effect.