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Mask feathering question

Posted: July 19th, 2016, 9:33 pm
by Marpel
I was working on an image (7360 x 4912) with a blown out section of sky and decided to substitute a section from another image.

My initial effort was to generate a mask using the flood fill tool within the mask dialogue, then adding a significant feather radius by raising the feather number considerably. This, of course, resulted in my computer stalling with a 9 minute count-down. After it took a couple more minutes to cancel the operation, I tried the highlight curves mask which I generated (and use considerably) a few years back when Den introduced it (well prior to the latest PWP version which includes it in its tools) and moved the bottom point to the left while moving the top left point towards the right. (Hopefully, I explained all that properly). Now the question:

Is using the mask curves dialogue, as described above, pretty well the same as generating a hard edged mask followed by a large feathered radius?? And, if the answer to that is "yes", is there an easy way to judge the resulting feathering when adjusting the slope angle of the curve? Or is it just a guesstimate each time?

Thanks,

Marv

Re: Mask feathering question

Posted: July 19th, 2016, 10:08 pm
by jsachs
Feathering is purely geometrical so the falloff rate is constant. If you use mask curves, the falloff rate depends on the image data - a sharp edge will fall off faster than a subtle gradient.

Re: Mask feathering question

Posted: July 21st, 2016, 7:40 pm
by Marpel
Jonathan,

Thanks for the reply.

I didn't even think of the different fall-off rates which are impacted by the data of the mask curve, but it makes sense now that you mentioned it. Interesting stuff.

Marv