1. Overview I recently visited my old junior high school in Boise, Idaho. A new
school had replaced it and only the entrance of the original building
was left standing. My nostalgic pilgrimage occurred in the late
afternoon, shortly before sunset and the edifice was backlit. These
challenging lighting conditions meant that in order to get a decent
exposure of the wonderful educational graphics over the window, the late
afternoon sky would be blown out. We'll drop in a new sky using the
Color Range command and the new Masks panel in CS4. (The new sky has
already been placed in the practice file as a separate layer.)
[ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذه الصورة] 2. Add a pixel mask Click on the Building layer in the Layers panel to make sure it's
active. In the Masks panel (Window>Masks), click on the Add a Pixel
Mask icon in the top-right corner of the panel (it's the icon on the
left). You'll see that a layer mask has been added to the Building layer
in the Layers panel. Now click on the Color Range button near the
bottom of the Masks panel to bring up the Color Range dialog.
[ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذه الصورة] 3. Samples colors with eyedropper In the Color Range dialog, make sure that the Invert box is checked
on and the Fuzziness is set to 40. Use the Eyedropper to click on the
sky above the building. Most of the white sky is immediately masked,
revealing the new sky layer underneath. This is very useful because you
can see the mask being created live. In previous versions (and if used
apart from the Masks panel in CS4), the result from using Color Range is
always a selection, not a mask. Use the plus Eyedropper to click in the
lower-left windows to make those areas totally black in the Color Range
preview. Click OK.
[ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذه الصورة] Fine-tuning with the Masks Panel 1. Control density of mask The Masks panel offers two dynamic sliders (Density and Feather) that
can be adjusted and readjusted at any time. Density controls the black
areas in the mask: 100% is total black and anything less than that
becomes gray. This functions like an opacity setting for the black areas
of the mask. Choosing a lower Density will allow more of the original
white sky to show through, and thus minimize the brightness of the new
sky layer underneath. In the past, this type of mask editing had to be
made using Levels or Curves. For this example, we left Density at 100%.
[ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذه الصورة] Mask Density 100% (image on left); Mask Density 50% (image on right)
2. Control feather of mask Feather controls the hardness of the mask edge. In previous versions,
this was accomplished by either feathering a selection before you
turned it into a mask (not ideal, because you couldn't see how much
feathering you might need) or by using the Gaussian Blur filter on the
layer mask. As this is a dynamic control, meaning it can be changed at
any time, it's a welcome masking improvement in CS4. For this example,
we need to apply the edge modifications another way, so leave the
Feather set to 0 pixels.
[ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذه الصورة] Feather = 0 px (on left); Feather = 5 px (on right)
3. The refine mask dialog There are a few errors on the mask edges in some areas, particularly
along the vertical window frames. To fix this, click the Mask Edge
button in the lower portion of the Masks panel. The controls in Refine
Mask are the same as Refine Edge, but they affect a mask and not a
selection, allowing you to see in real time how the edges of an
adjustment layer's mask are affected. If you're creating a selection
that will be used to create a layer mask, apply your edge modifications
in the Refine Mask dialog where you have a better view of what's
happening-see next Step.
[ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذه الصورة] 4. Adjust settings in refine mask Choose View>Actual Pixels to zoom the image to 100%. In the Refine
Mask dialog, click on the Standard preview icon (circled above). This
shows the mask as a selection edge, which is totally useless if you're
working on a mask because it obscures the very edges we need to see, so
choose Command-H (PC: Ctrl-H) to hide the selection edges. Set the
Feather to 0.8 pixels to slightly soften the edge, then set the
Contract/Expand slider to -35 to "fit" the mask edge tighter to the
building. Finally, set the Contrast to 20 to further fine-tune the edge.
Click OK.
[ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذه الصورة] Note the difference in the Before (on left) and After (on right)
5. Select the sky in the windows The adjustments we made in the Refine Mask dialog did a good job at
creating a better fit for the layer mask, but we still need to do some
manual touchups. For this photo, we'll use the Brush tool to fill in
areas of bright, specular highlights on the vertical window frame that
were initially selected by the Color Range command. Click on the Eye
icon at the bottom of the Masks panel to temporarily disable the layer
mask. Use the Quick Selection tool (W) and drag across the sky area
inside each of the window frames while holding Shift to select those
areas.
[ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذه الصورة] 6. Paint white on mask Choose Select>Inverse to select everything except those sky areas.
In the Layers panel, click on the layer mask to be sure that it's
active and also to enable the mask. Use the Brush tool (B) and paint
with white at 100% Opacity. Depending on the selection, you may need to
apply further edge feathering.
[ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذه الصورة] 7. Add curves As a final touch, I added a Curves adjustment layer that applied a
slight contrast boost to the building layer. With the Curves layer
active, I clicked the third icon from the left at the bottom of the
Adjustments panel to clip the adjustment so that it only affected the
building.
[ندعوك للتسجيل في المنتدى أو التعريف بنفسك لمعاينة هذه الصورة] 
