"Noise"? Did you say "Noise"?
You have chosen well.
You get a dramatically increased level of noise if you emphasize the red (as you did here) or the blue channels.
The reason for this the the Bayer Pattern of the sensor. Look at the pattern below. If you notice, 50% of the pixels are green, 25% are blue and 25% are red. So the blues and reds end up being peppered in the shot which contains the lions share of green information. By selecting either the blue or red, you are effectively discarding 75% of the information of the shot, including 75% of the luma information. As a result you get a much more pixelated look.
The method I have chosen to deal with that problem is called "Getting a 5D", which has a lot more pixels - with less weight given to each one.
Though I have not tried it, I would suppose that using an edge mask and a Gaussian blur on only the red channel should help.
Rad
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