Intricate Selections with low contrast

[bestremera]

Hello,
I'm having trouble with this kind of selection.
Need to make a new layer of clouds only.
Note the intricate 'see-through' parts of the upper antennae.

Blue channel doesn't seem to work because the clouds are dark too.
Maybe I'm just not good at it.

What steps can I take to separate the clouds, even where they peak through the intricate building parts?
I have a ton of images like this to work with.

Thanks, Bob

[Ziaphra]

The pen tool comes to mind.

[bestremera]

Also, any help on how to soften or eliminate the artifacts throughout the clouds?
That's why I need a new layer of the clouds only.
I've did a quick down and dirty 'lens blur' on them and it seemed to work pretty well.
But any other techniques you can offer would be appreciated.

Thanks again, Bob

[bestremera]

Thanks Ziaphra,
I'm pretty decent with a pen tool but there a just too many little nooks and crannies.
Hoping for a CS3 technique that might be faster.

[Swampy]

Do you have the original color version? If you use CS3, you may find my tutorial on "Masking the Sky" of help, but you need a color version. If it works on the color version, you should be able to copy the resulting alpha channel from the color version to the sepia one and apply it as a mask.

[jam1212]

You could try duplicating the blue channel and dodging and burning right on that. There should be enough contrast on the top to get a pretty good mask going for those upper parts. For the rest, just use the pen tool as Ziaphara said. The straight lines should make it pretty simple.

[SteveB2005]

Try this with Calculations to cut a mask. You can use the pen tool for the straight edges as well.

[KR1156]

use the pen tool for the hard edges of the buildings to make an initial mask, for the entenna there is plenty of contrast to pull it from a channel. and if you need to fine-tune anything, just use a 100% opacity brush with a hard edge to paint in those little spots of the antenna.

after you piece together a good mask....give it the approriate blur to soften the edges so it is believeable, and doesn't have that cutout feel.

[bestremera]

You're all great. I'll proceed to give all these options a try.

Thanks, Bob

[bestremera]

Wow Swampy, that IS a great tutorial. Since I start with color for all my capture, I'll be practicing this one until I can do it blindfolded.

Thanks, Bob

[ktg222]

I used a modified version of Russell Brown's tutorial to make a mask of the building on a background copy layer. I put a blue sky layer below the background copy layer and used Blend If to bring back in the clouds. I reduced he opacity of the blue layer to make it less intense.

[Daviskw]

Hi there

I used a pen selection all except the antennae...There I applied image to the red layer and used multiply. Added part of a new sky then played a little...great image

Butch

[bestremera]

You guys are Amazing!
What I don't know about selections . . . .
How do you start with one method of selection then add another different method.
I only know how to start and finish with one method

Thanks some more, Bob

[cricket1961]

I can't resist a good calculations challenge!

Hard to tell because of the jpg compression, but try these settings and probably adjust from there.

Chris

[Swampy]

Bob, Thank you. Glad you liked the tutorial. :-)

You can start a selection with one method and use that selection to create a mask. Then, with the mask selected, you can continue using other selection tools fill each newly created selection, on the mask, with the appropriate mask color (black or white).

For example, let's say the subject is a car. I'll use the marquee tool to basically select the area of the car, and create the mask with that selection. This just removes the gross background areas. Then I'll use the pen tool and select more detail around the car and add that to the mask by filling each new selection with black (on the mask). I just keep cutting away more and more of the background this way until all the background is hidden.

[Markzebra]

Chris is obviously a bit of an expert with the Calculations - try his method, and then use dodge and burn brushes to modify the mask, these can be set up with low opacity color dodge and burn mode brushes, or directly with the burn or dodge tools

Personally I would have probably done the whole thing with the pen tool, although the method above may in practice be better. Nice shot.

[lurch]

Chris: Many thanks for providing a bit of insight into thinking about calculations - it made this one easy. Penned the building bottom, used overlay paintbrush on building top and sky, touched up layer mask with normal paintbrush in black or white as appropriate. Since this was an extraction exercise I just replaced the sky with solid color.

Bestremera: Great shot!

[bestremera]

Thanks Swampy and everybody,
I'm not going to stop until I get this selection/mask thing licked.
Bob

[musicman_bmh]

chris,
how are you getting the correct numbers to put in for the calculations? And are you inverting the channels before you open calculations?

[PreachersPhoto]

Just another way of doing things, in the interest of offering options.

A technique I have found that works well with a lot of straight edges like you have in this picture, sounds involved, but it takes longer to describe than to do.

Duplicate the base layer, create a level adjustment mask by clicking the layer icon at the bottom of the layers pallette (it looks like a yin/yang thing) adjust levels until there is a clear separation between the building and the sky (Building will be dark, sky light in this example).

Merge the level adjustment layer into the second layer. Draw a simple square or circular marquee around the spire and copy the section onto a third layer.

Hide layers 1 and 2.

Then, zoom way in and, using the color picker (Select>Color Range) pick out the sky colors in the little "windows" in the spire. Remember,you can choose multiple colors or levels of color by choosing the dropper with the + next to it. Once you click OK, all the colors you chose will be highlighted.

Invert the selection and copy it to a new layer. You now have 4 layers. Hide layer 3.

Select the 4th layer subject by holding down CTRL and clicking on the layer icon. Now select the base layer again, and , right click within the marquee, copy the selection to a new layer.

You can then use the polygon marquee tool to select the rest of the building as normal and copy it to a new layer. Once you have that done, just merge the clean spire with the clean cutout of the building.

Now you can do whatever you want with the rest (adjust for the sky etc) or you can choose the new building cutout, invert and copy the sky to a layer to work in it alone.

See the link for a screen shot of my layers pallette.
http://i49.photobucket.com/albums/f2...ups/Picker.jpg

Hope that all makes sense!~

[cricket1961]

Musicman

The inversion of channels is done within Calculations. Take a look at the screenshots
I attached to my previous post.
Sorry that they need to be downloaded. I haven't figured out how to post so they show.

As for the numbers, just years of doing it. For the record, with the add that I used,
the first numbers for simplicity's sake, in the add section are equivalent to opacity,
the second set is the equal to the light coming through one into the other, and the third set is bringing back the original.

Chris

[Daviskw]

Chris ..May I ask what procedure you are usually using calculations for...and can't the same thing be done in apply image but needing multiple steps?

Butch

[cricket1961]

Yes and no. The benefit of calculations is that it allows you to make intricate composites and save out as a selection, channel, file.

Apply image is exactly as it says it is, it takes a mixture of two channels/images and applies it to the active image. No selections, and no real benefit from the channels.

I mostly use calculations to make masks of a lot of variety and or to create a new channel to replace a channel in the active image by taking the resulting channel made and swapping out with the live one.
I will also create 1/4, mt,3/4, and sh mask this way that target those frequencies only. Depending on the way you do it it can do some marvelous things. In Katrins 1st and maybe carried over to her 2nd edition of Retouching and Compositing I go over a bit of apply image and in the 3rd edition there is someone else who brings in some good stuff also.

The two can be used together to start or finish great things.

Chris

[Daviskw]

Thanks Chris...I'm afraid it is beyond my capabilities to understand just now..but I've found things seem to fall in line over time and with experience. Some day I'm sure I'll go...Hey I know what he meant..lol

Thanks again

Butch