《The Magic Wand revealed》 -----本字幕由雷天音 整理制作----- We're going to start things off with a look at the oldest of the automated selection tools inside of Photoshop and that's this
【----QQ 568031962----】 guy right here, the Magic Wand tool, go ahead and select it from the Quick Selection tool flat menu or press the W Key, a
【----ACELY STUDIO----】 couple of times, what have you. I also want you to open this image right here, it's called Gradient demo.psd and it's
found inside the 04_ selection_tools folder. Now the magic wand has received a fair amount of abuse over the years, not
the least of which was told out by yours truly, I must admit, I've long maintained that this is one of the tools inside of Photoshop
othat over promises and under delivers. Folks have gone so far as to call it the tragic wand these days and
well, I think that's hilarious actually and somewhat accurate. The truth of the matter is if you know what to expect
from the Magic Wand tool, it delivers with flying colors and the fact that it can select groups of colors automatically
at a time, sets the stage for masking because after all, when we're masking an image, we're using the image to select itself based
on its inherent colors and contours and so on. All right, so here's
how the Magic Wand tool works. If you click on a point,
then you're going to select neighboring colors, neighboring adjacent colors by default, so I could select a bunch
of medium oranges by clicking in the center of this gradient, I can select a bunch of dark oranges by clicking over
here in the left, I could select this entire blue bar by clicking on it as well and this is all the turn by these options
up here inside of the Options bar. Now, what you're seeing right now are the default settings for this tool, tif you're
seeing different settings you can right click on this Magic Wand icon on the far left side of the Options bar and then you can choose
to reset tool command in order to reset those default settings.
Now, then I'm going to press Ctrl+D, or Cmd+D so we have nothing selected inside of this image, and I'm going to click right
here in the center of this top gradient. Actually, first I'm going to press Shift tab so I get rid of those palettes in the
right hand side of the spring and then I'm going to click right there in the center of this top gradient. Now, by virtue of the
fact that the tolerance value is set to 32, which is 32 luminance levels incidently,
and you may recall where luminance levels are concern, zero is black, 255 is white. So we have 256 different brightness
values, different luminance levels on a channel by channel basis inside of an eight bit per channel image and even if we're working
inside of a 16 bit per channel image, the Magic Wand tool, just like many of the functions inside of Photoshop speaks to us in 8 bit language.
So right now we're seeing a tolerance value of 32, that means it's going to select 32 luminous levels lighter and 32
luminous levels darker then the click point. Now there's a rumor out there that it's actually the entire range that
measures 32 luminous levels, so we're going 16 in one direction and 16 in the other, that that is not true. It's 32 one way
and 32 the other, so we have a total of 64 different luminous levels selected at this point.
Now let's say that you want to select more luminous levels at a time, more of this gradient in other words, then you
would go ahead and change this tolerance value if you wanted to, so I'll up it to 100 for example, 100
different luminance levels and I'll press the Enter key or the Return key on the Mac and notice nothing happens. That's
because this is a static control that affects not the current selection, but the next selection that we create.
So, I'll press Ctrl+D, Cmd+D on the Mac in order to deselect that area and then I'll click again and notice this time it
selects 100 luminous levels lighter and 100 luminous levels darker.
Now it's calculating this selection on a channel by channel basis.
Let me show you what I mean by that. I'm going to press Ctrl+1 or Cmd+1 on the Mac in order to switch to the red channel,
now I'm going to press Ctrl+D or Cmd+D and I'm going to once again click in the center of this top gradient bar here, right smacked up in the center
and this time it goes 100 luminous levels darker inside of the red channel and only the red channel, cause it can't see
the other channels at this point and then it goes all the way over to the right side, because this entire area from the
middle to the right hand side of the image is filled with white, inside of the red channel so goes ahead and expands the
selection all the way to the right side of the image.
Now I'll press Ctrl+2 or Cmd+2 on the Mac to switch to the green channel, let's deselect that area by pressing Ctrl+D
or Cmd+D again and then click in the center once again and notice what it does this time, it goes 100
luminous levels to the right, 100 luminous levels to the left and it actually selects this center bar of color too, because
that's a flat gray inside of this green channel that corresponds to medium gray up here inside of the gradient, which is
basically the color that I clicked on and then it expands down here into this other gradient as well because, these
are all adjacent colors. Now just one note, if it looks as if the center bar here is a little bit of a gradient if it
looks kind of light over here on the left hand side, and a little bit dark over here in the right hand side, that's an optical illusion,
my friends, this is an entirely flat color that you see in front of you, is just your eyes compensating for the fact that it's
set against dark colors over on the left and light colors over here on the right. All right, now, let's switch over to the blue channel
by pressing Ctrl+3 or Cmd+3 and the Mac.
I'm going to go ahead and deselect this image once again, and I'm going to click in the center of the gradient, it goes 100
luminous levels lighter and it goes all the way over to the left because this is black, this whole area is black here
inside of the blue channel. So why do we end up getting a selection like this
inside of the RGB composite, so I've pressed Ctrl+~ or Cmd+ ~ on the Mac to switch back to the RGB composite, I
deselected the image, I clicked there in the center, we just get this a relatively small selection as a result. Well, what the
Magic Wand is doing is it's completing the selection in the red channel and the green channel and the blue channel
independently and in its finding the intersection of those three selections and that's what it keeps inside of the composite view.
-----本字幕由雷天音 整理制作----- -----更多Lynda字幕请访问我的人人----- -----联系邮箱：acely@126.com----- All right, so that's how tolerance works up here inside of the Options bar. I'm going to show you how contiguous and
sample all layers work in the next exercise.