Hi,

I've included an image in which I'm trying to mask out the clouds.
I tried to include a copy of my results but the attachments button only let me manage my existing uploaded file and now upload a second image.

The problem is with masking a sky that has texture and a fairly wide tonal range (for clouds anyway) from a complex subject with many small and large openings that the clouds can be seen through.

I convert to black and white and dramatic skies are my personal holy grail.

My best attempt has gaps throughout the image.

Can someone give me a real detailed tutorial of how best to make this mask and accomplish my end result?

Thanks, Bob

Bob,

Is this what you are trying to achieve?

k

utilize the blue channel for your mask. do it.

Yes to both or you.

I did use the blue channel. It had the most contrast.
But my mask wasn't complete, there were gaps along several of the vertical cables on the lower right and other areas.
KTG222, your mask is so tight, it's exactly what I want to achieve before I convert to b&w.

Once you find the correct channel, what are the steps I would use to 'utilize' it and make a proper, tight mask like yours?

Thanks again, Bob

Bob, if you have Photoshop CS3 you can use the B&W Adjustment Layer without having to mask. There are two methods. The 1st is to just add the adj layer, place the eye dropper tool on the area of the sky which is Blue and then hold down the mouse / pen and drag the scrubby slider to the left to darken. Do the same to the white cloud to brighten it and add contrast.
If you would prefer to see what is happening in color before going to B&W, add the B&W adjustment layer with no adjustments (just click OK) and change the layer's blend mode to Luminosity. Then double click the adj layer icon to bring up the sliders. Use the eyedropper and scrubby sliders to build the contrast where you want it. When you are done, just change the blend mode of the adj layer back to Normal (or other blend mode).
Regards, Murray

Another approach is to use non-RGB data.

I copied the file and converted to LAB mode.
Duplicated the B channel and increased 'contrast' in it
Inverted the channel, copied it, and pasted the copy in as a new layer.
Set the blending mode to Linear Dodge.
Boosted contrast with a small Curve tweak.
Convert back to RGB for the finishing up.

Even on this small JPEG, it maintained most of the details in the vertical cabling; on a larger file, much more contrast boosting could be done to get the major cables to black.

On the other hand, if you simply wanted a more dramatic sky and don't need a mask for another purpose, that's easily done without manual masking: use a contrast boosted and inverted B channel as a mask on a darkening Curves or Levels layer. Since only the blues will be affected, and the bridge and clouds don't have any blue, the sky gets more contrast.

Thanks Kevin and Mistermonday,

I'll try both of those options.
By the way, I have CS2.

Bob