Luminosity, or
lighting, is what you see in a black and white photograph.
However the luminosity of a color photo is also very important in
the quality of that image. The basic Photoshop tools of
luminosity is levels, brightness & contrast, and shadows &
highlights. We will examine these tools as well as look at
luminosity adjustments based on the colors in the image using the
luminosity blending mode. We will use selections and layer masks
on adjustment layers to localize needed corrections.
Adjusting Lighting using Adobe Camera Raw
- In the main menu select File - Open As
- In the "Open As" dialog box select Camera Raw in the Open As drop-down menu
- Select the folder location of your image in the Look in box.
- Select your file that you wish to open. Click "Open". The Camera Raw dialog box will come up.
- On the default window of the ACR dialog box Exposure, Recovery,
Fill Light, Blacks, Brightness, and Contrast all adjust the luminosity
of the image.
- In the second window of the ACR sharpening and luminance noise
reduction involve the luminosity of the image. Note the
sharpening is a pre-processing sharpening.
Adjusting Lighting using Shadows & Highlights
- Open an image with the command "File - Open"
- Use the command "Layer - Duplicate Layer" to create a second layer. Name the Layer "base"
- Use the command "Enhance - Adjust Lighting - Shadows/Highlights" to bring up the Shadows/Highlights dialog box.
- Use the "Lighten Shadows" slider to brighten the shadow portions of your image.
- Use the "Darken Highlights" slider to darken your highlights. Do not do this too much or you may get halos in your image.
- Increase the Midtone Contrast to make the image more pleasing.
- Shadows/Highlights mostly acts on the luminosity of the image.
But it can also change the color somewhat. To counteract
that effect change the blending mode of the top layer to "luminosity".
Brightness & Contrast Adjustment Layer
- Open an image.
- Use the command "Layer - New Adjustment Layer"
- Select "Brightness/Contrast"
- Click OK
- In the Adjustments palette you may use to brightness and contrast sliders to adjust your image as you would like
- Note: Many authors think this control should not be used since there are better ways to achieve the same result.
RGB Channels with Levels Adjustment Layer
- Open an image.
- Use the command "Layer - New Adjustment Layer" and create a Levels adjustment layer.
- On the layers palette change the blending mode of the Levels
adjustment layer to "luminosity" by using the drop down menu.
(Luminosity is the bottom choice.)
- In the levels dialog box move the left (shadows) slider to the right until it just touches the histogram.
- In the levels dialog box move the right (highlights) slider to the left until it just touches the histogram.
- Adjust the middle (midtone) slider as needed.
- In the levels dialog box use the drop down menu to choose the red channel.
- Repeat steps 4, 5, and 6 using the red channel.
- Repeat steps 7 and 8 for the green channel
- Repeat steps 7 and 8 for the blue channel
- You may go back and tweak your results for any channel.
Converting to Black & White with Gradient Adjustment and Levels Adjustment Layer
- Open an image in Camera Raw
- Make corrections in Camera Raw
- Use the command "Layer - New Adjustment Layer" and create a Gradient adjustment layer.
- In the drop-down menu select black-white. This is the
third choice from the left. Your image will now be black and
white.
- Use the command "Layer - New Adjustment Layer" and create a
Levels adjustment layer. Change its blending mode to "luminosity"
- Do steps 4 through 10 from the section "RGB Channels with Levels
Adjustment Layer", This will adjust the black & white image
based on the underlying colors.
Bonus Section -- make the subject appear in color against a black and white background
- Turn off all layers except the background layer (by clicking on the "eye" icons on the left in the layers palette.)
- Make the background layer active by clicking on it in the layers palette.
- Create a duplicate of the background with the command "Layer - Duplicate Layer". Name the new layer "base"
- Select the subject using any of the selection tools. Quick select frequently works.
- Turn on all layers (by clicking on the "eye" icons on the left in the layers palette.)
- Make the Gradient layer active. Click on the white layer mask icon.
- Make the foreground color (bottom of the tool bar) black by clicking on the default icon.
- Select the brush tool. With the '[' or ']' keys make the brush fairly large.
- Paint black over the selection. Note: This will
actually be painting on the layer mask. Also the painting will
not occur outside the selected area.
- The black will block the effects of the gradient layer and thus the color image of the subject will appear.
- Type control D to remove the selection.
Bonus Section 2 -- blur the background.
- Make the base layer active.
- Use the command "Filter - Blur - Gaussian Blur" to bring up the Gaussian Blur dialog box.
- Set the radius to somewhere between 5 and 15 as desired. Click OK.
- With the command "Layer - Layer Mask - Reveal All" create a layer mask for the base layer (new in PSE 9)
- With the command "Select - Reselect" bring the subject selection back up.
- With black as the foreground color and with the brush tool selected paint black on the layer mask.
- This will hide the blurred image on the subject making it appear sharp.
Homework
One does not learn Photoshop by
watching. You have to actually do it. So while these
lessons are fresh on your mind get some of your images, get to a
computer that has on it Photoshop Elements and repeat for yourself
(maybe several times) the lessons given here. When you are
comfortable that you know how to do these things make edit several
images (up to five) and bring them to either Print Sig or Digital Sig
on Tuesday in the Camera Club.