Lighting and Color Adjustments IN THIS CHAPTER Adjusting lighting and exposure Changing color balance Applying lens filter effects to photos Making specific color and tone adjustments t
Trang 1Lighting and Color
Adjustments
IN THIS CHAPTER
Adjusting lighting and exposure
Changing color balance Applying lens filter effects
to photos Making specific color and tone adjustments to images Creating custom black and white photos
Making colors pop out of images
Adjusting levels in images
to restore detail
The most common edit that you will perform on photos is correcting
the lighting and color Photoshop provides a number tools that cor-rect the color and lighting in different ways As you become more familiar with these tools, you can adjust problems in images such as
overex-posure, underexoverex-posure, and color casts You also can make minute
adjust-ments to images that make a big difference in the overall appearance
This chapter discusses most of the tools available in the Image ➪ Adjustments
menu and the Adjustments panel Many of these tools have overlapping
functionality, so you are not locked into one specific tool to adjust an image
Try all the tools we discuss in this chapter, and then use the tools that work
best for you
Note
Remember that most of the techniques you learn in this chapter can be applied
as an Adjustment layer That means you can use a selection to create the
Adjustment layer and then apply the color adjustments only to that specific
area of the image This allows you to be much more aggressive with the
changes you make because you aren’t modifying the rest of the image n
Applying Quick Adjustments
to Light and Color
Photoshop provides several tools that allow you to make quick adjustments to
the lighting and color in images In the background, these tools are simply
adjusting the level values in the color channels of the image However, these
tools provide a nice interface to adjust them in specific ways I like to think of
Trang 2The following sections discuss using Photoshop’s adjustment tools to fix lighting and color prob-lems and make subtle adjustments that enhance the appearance of photos These tools work well for most of the problems you encounter in images Later in this chapter, we discuss using the Levels and Curves tools to make more complex adjustments that the simple tools can’t do
Brightness and contrast versus exposure
One of the most common problems you may encounter with photos is that they are either too dark
or to light due to lighting or exposure problems Photoshop provides two tools to quickly fix light-ing problems in your images: the Brightness/ Contrast tool and the Exposure tool
To understand how these tools work, first look at the reason a photo is too dark or too light
Photos are too dark because not enough light was received by the camera, either because the aper-ture was too small or the exposure time was too short The end result is that too many pixels are in the low levels of all color channels, making the image dark with limited details The opposite is true for photos that are too light
Both the Brightness/ Contrast tool and the Exposure tool can be used to correct photos that have been overexposed or underexposed However, they work a bit differently and produce different results
The biggest difference between the two tools is that the Contrast and Brightness tool works with the color space that exists in the image and the Exposure tool works with a linear color space called gamma 1.0 Because the Exposure tool is not limited to the current color space, it can make more dramatic lighting corrections The downside of the Exposure tool is that when working out-side the color space in the image, some data loss occurs in the form of more abrupt changes between tones
Tip
The Exposure tool was designed to be used in HDR images with much greater tonal ranges, even though it does
work with 8-bit and 16-bit images A good rule to follow is to use the Contrast and Brightness tool when working
with 8-bit images and the Exposure tool when working with HDR images Then, if you can’t get the lighting
cor-rection you need with the Contrast and Brightness tool, you can use the Exposure tool to get a better result n
Using the Brightness/ Contrast tool to adjust lighting
The Brightness/ Contrast tool, shown in the Adjustments panel of Figure 13.1, allows you to adjust both the brightness and contrast levels in an image Here’s how:
l Brightness: Adjusting the brightness up increases the level values of all color channels in
an image, making the image lighter Adjusting the brightness down decreases the level val-ues of all color channels in an image, making the image darker
l Contrast: Adjusting the contrast up spreads the level values out, generating more contrast
between the levels in the image giving Adjusting the contrast down contracts the level values more tightly, giving less contrast
Trang 3Typically, to correct an image that is underexposed, you need to increase the brightness first and then increase the contrast to bring back some of the detail lost by increasing the brightness To correct an image that is overexposed, you need to decrease the brightness and then increase the contrast to bring back the detail
Figure 13.1 shows the effects of adjusting the brightness and contrast on a photo that was underex-posed Notice that by increasing the brightness and contrast, we can see more details in the photo
FIGURE 13.1
Increasing the brightness and contrast on an underexposed image reveals more of the detail
On the Web Site
The image shown in Figure 13.1 can be found on this book’s Web site as Figure 13-1.psd You can open it in
Photoshop and try adjusting the brightness and contrast n
Using the Exposure tool to adjust lighting
The Exposure tool, shown in the Adjustments panel of Figure 13.2, allows you to adjust the expo-sure values of the image, increasing or decreasing the lighting and contrast The Expoexpo-sure tool allows you to set the following values to adjust the lighting and contrast:
l Exposure: This adjusts the highlight end of the tonal scale Adjusting the exposure up
lightens the lighter pixels Adjusting the exposure down darkens the lighter pixels This setting has only a minimal effect in the darkest pixels of the image
l Offset: This adjusts the darker and middle end of the tonal scale Adjusting the offset up
lightens the darker pixels Adjusting the offset down darkens the midtone and darker pix-els This setting has only a minimal effect in the lightest pixels of the image
l Gamma Correction: This applies gamma correction to the image Adjusting the gamma
value down (between 1 and 0) darkens the image and adjusting the gamma up (between 1 and 10) lightens the image
Trang 4l Black eyedropper: When you use the black eyedropper to select a pixel in the image, the
Offset value is adjusted by setting the selected pixel to zero
l White eyedropper: When you use the white eyedropper to select a pixel in the image, the
Exposure value is adjusted by setting the selected pixel to white White is 1.0 for HDR images and 0.0 for non-HDR images
l Midtone eyedropper: When you use the midtone eyedropper to select a pixel in the
image, the Exposure value is adjusted by setting the selected pixel to midtone gray
Note
You also can select a preset exposure value of minus 1.0, minus 2.0, plus 1.0, plus 2.0, or a custom value from
the Exposure drop-down menu shown in Figure 13.3 This allows you to create a custom exposure setting that
can be saved using the Save Exposure Preset option in the Adjustments panel menu The custom exposure can
then be applied to several different images that had the same exposure problems n
Follow these steps to use the Exposure tool to adjust the lighting and contrast of an image in Photoshop:
(refer to Figure 13.2).
layer to the image
The Exposure dialog box, shown in Figure 13.3, appears, allowing you to adjust the
exposure settings
FIGURE 13.2
Selecting the Exposure button from the Adjustment panel home pane
Trang 53 Try to use the eyedroppers to set a baseline for setting the exposure
Use the black eyedropper to select an item in the image that should be black, the white eye-dropper to select a white pixel, and the midtone eyeeye-dropper to select a gray pixel On many photos, the eyedroppers simply don’t work; if they don’t work, just move to the next step
detail as possible
Don’t worry if the image looks a bit faded out at this point.
Exposure, until the image is less faded.
overall lighting and contrast in the image.
Figure 13.3 shows the effects of adjusting the Exposure, Offset, and Gamma Correction settings on
a photo that was severely underexposed Notice that increasing the Exposure allows you to see much more details in the image However, the image is now a bit grainy because we adjusted the values outside the tonal range of the image
FIGURE 13.3
Increasing the Exposure and decreasing the Offset on an underexposed image in the Exposure tool reveals
much more of the detail in the image
Black eyedropper Mid-tone eyedropper White eyedropper
Exposure drop-down menu
Trang 6On the Web Site
The image shown in Figure 13.3 can be found on this book’s Web site as Figure 13-3.psd You can open it in
Photoshop and try adjusting the exposure n
Changing the color balance
The Color Balance Adjustment tool allows you to adjust the balance between each color in the color channels with its complementary color Changing the color balance adjusts the overall hue of the color channel This allows you to quickly fix a single color that is out of place or adjust all the colors in the image
Tip
The Color Balance tool is extremely useful when you are trying to add color to a black and white image You
can select specific areas of the image and adjust the color balance to those areas to create color tones n
l Tone: A really nice feature of the Color Balance Adjustment tool, shown in the
Adjustments panel of Figure 13.5, is the ability to specify whether you want to adjust the color balance for the pixels in the highlights, midtones, or shadows range Separating the color balance into tonal ranges allows you to focus in on one specific tonal range, fixing the color for that range before moving on
l Color Sliders: To adjust the color balance, simply drag the color sliders to the left or right
to adjust the balance between each color and its complementary color Adjusting the bal-ance shifts the hue of the color, for example, from red to cyan or blue to yellow
l Preserve Luminosity: You can specify whether to preserve the luminosity, which
typi-cally is the best idea Preserving the luminosity forces the color balance adjustments to change so that the luminosity stays the same This keeps the color balance adjustments from washing out the image
The following example demonstrates how to use the Color Balance Adjustment tool to fix the col-ors in an image that has been overloaded with a single tone:
1 Open the image in Photoshop, as shown in Figure 13.4
The orange leaves of the background have really added a yellow hue to the entire image, and none of the colors really pop out
shown in Figure 13.5.
Adjustment layer to the image
The Color Balance pane appears, allowing you to adjust the color balance settings.