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Inverted highpass-bandpass

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  #1  
Old 03-31-2012, 12:05 PM
Rust Rust is offline
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Inverted highpass-bandpass

I wonder why some people( i think Godmother) prefer Inverted highpass for softening skin instead of a band pass filter?
My second question is : When you creating a split with a low radius let`s say 5pxl g.blur -then apply imag. The next step is to copy the low layer and blur it with a g.blur of 15pxl. Which frequencies are you eliminating? is it the frequencies between 5 and 15 pxl?
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Old 03-31-2012, 12:24 PM
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mistermonday mistermonday is offline
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Re: Inverted highpass-bandpass

Yes, but you are not eliminating them - you are selectively blurring them.
Regards, Murray
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Old 04-01-2012, 09:31 AM
Rust Rust is offline
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Re: Inverted highpass-bandpass

Ok thanks mistermonday but do you know why people prefer IHP over bandpass?
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Old 04-01-2012, 10:00 AM
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mistermonday mistermonday is offline
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Re: Inverted highpass-bandpass

A well known retoucher and proponent of the technique came up with the term IHP because as part of the process, a layer which has has a high pass filter applied is then inverted, and as you may know, the inverse of a high pass is actually a Gaussian Blur.
Technically, what you are producing is not a bandpass but a Bandstop. You are allow all of the edges whose radii are lower than or equal to 5 px to be seen unaffected, and all of the edges whose radii are greater than or equal to 15 px to also be seen unaffected, while all of the edges in between are to some extent blurred / softened / contrast reduced and hence that band has been filtered out or stopped. IHP is not the official, nor technical term for the technique.
Regards, Murray
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Old 04-04-2012, 01:03 PM
Rust Rust is offline
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Re: Inverted highpass-bandpass

Thanks for clarifying this Mister Monday, appreciate it.
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