PS6: Feather puzzle

Version 6.

I ran some tests by creating two images: one white and one black. Next, I selected a small area of one and copied it to the other.
Now then, without Feather the border between the copied and underlying color was solid, as expected, i.e. instant transition from white to black.

However, once I applied Feather the number of affected pixels for the transition was not what I expected! For example:

Feather: 1 – took 6 pixels to go from pure black to pure white Feather: 2 – resulted in transition needing 10 pixels
Feather: 3 – took 14, and so on…

I would’ve expected a feather of 1 to take, well… 1 pixel. I could also understand if Feather of 1 resulted in a 2-pixel transition: 1 on the white side and 1 on the black. But 6!?

What’s going on here?

Don.

Version 6.

I ran some tests by creating two images: one white and one black. Next, I selected a small area of one and copied it to the other.
Now then, without Feather the border between the copied and underlying color was solid, as expected, i.e. instant transition from white to black.

However, once I applied Feather the number of affected pixels for the transition was not what I expected! For example:

Feather: 1 – took 6 pixels to go from pure black to pure white Feather: 2 – resulted in transition needing 10 pixels
Feather: 3 – took 14, and so on…

I would’ve expected a feather of 1 to take, well… 1 pixel. I could also understand if Feather of 1 resulted in a 2-pixel transition: 1 on the white side and 1 on the black. But 6!?

What’s going on here?

Don.

its because of the gaussian bell routine used in calculating the feather.Without it the blend would be jaggy.You can count on each unit of feather radius taking 2.7 pixels in and 2.7 pixels out from the selection .

(Don) wrote in message news:…

Version 6.

I ran some tests by creating two images: one white and one black. Next, I selected a small area of one and copied it to the other.
Now then, without Feather the border between the copied and underlying color was solid, as expected, i.e. instant transition from white to black.

However, once I applied Feather the number of affected pixels for the transition was not what I expected! For example:

Feather: 1 – took 6 pixels to go from pure black to pure white Feather: 2 – resulted in transition needing 10 pixels
Feather: 3 – took 14, and so on…

I would’ve expected a feather of 1 to take, well… 1 pixel. I could also understand if Feather of 1 resulted in a 2-pixel transition: 1 on the white side and 1 on the black. But 6!?

What’s going on here?

Don.