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Adobe Photoshop CS5 – Illustrated
Unit E: Improving Images with Adjustment Layers
Objectives
Understand grayscaleInvestigate a grayscale imageUse the Brightness/Contrast adjustmentAdjust black and white points with levels
Adobe Photoshop CS5 - Illustrated
Objectives
Adjust the midpoint with levelsInvestigate an RGB imageUse the Color Balance adjustmentUse the Vibrance adjustment
Adobe Photoshop CS5 - Illustrated
Improving Images with Adjustment Layers
Images can come from anywherePhotoshop’s practical operations Improve image characteristics
• Color, contrast, overall effect
Adjustment layer Allows for adjustments applied to image
• Does not directly affect the artwork Called “non-destructive”
• Exists as a layer on the Layers panel
Adobe Photoshop CS5 - Illustrated
Understanding Grayscale
Grayscale digital image Each pixel: one of 256 shades of gray
256 shades of gray Creates continuous tone image illusion Grayscale range: 0-255
• Pixels grayscale value of zero: black• Pixels grayscale value of 255: white• Any number in between: light to dark gray
128: middle point in the grayscale range
Adobe Photoshop CS5 - Illustrated
Understanding Grayscale
Sampling pixels Identifying pixel information in the info
panels
Info panel displays the Grayscale readouts sample pixels in ink percentages Readout provides information for the
printed image resolution
Adobe Photoshop CS5 - Illustrated
Understanding Grayscale
Adobe Photoshop CS5 - Illustrated
Info panel settings
Sampling the lightest pixels in the Image
Investigating a Grayscale Image
Analyzing image appearance Identify highlights, shadows, midtones
Highlights Lightest image areas Pixels values in upper third of grayscale
range
Shadows Darkest areas Pixels in low third of the grayscale range
Adobe Photoshop CS5 - Illustrated
Investigating a Grayscale Image
Midtones Fall into middle grayscale range
Individual digital image pixels Illusion of continuous tone Smooth transition from shadows to
midtones to highlights
Creation of illusions Requires sufficient number of grays
available per pixel
Adobe Photoshop CS5 - Illustrated
Investigating a Grayscale Image
Adobe Photoshop CS5 - Illustrated
Shadows, midtones, and highlights identified on the
gradient
Image 3 shades of gray available per pixel
Image with 16 shades of gray available per pixel
Using the Brightness/Contrast Adjustment
Adjustments Operations affecting image appearance
• Manipulating brightness and contrast Can be made directly to pixels on a layer
• Cannot go back and readjust at a later time
Creation of adjustments layers Adjustments existing as layers on the
Layers panel Affect image Can be manipulated at a later time
Adobe Photoshop CS5 - Illustrated
Using the Brightness/Contrast Adjustment
Adjustment layer Can be hidden, re-shown, deleted at any
time
Brightness/Contrast adjustment Brightness: defined by grayscale value
• Higher the number, the brighter the pixel Contrast: represented by the relationship
between the highlights and shadows• Good when highlights and shadows distinctly
different in tonal range; not “flat”
Adobe Photoshop CS5 - Illustrated
Using the Brightness/Contrast Adjustment
Key to making adjustments Walk the fine line between going far
enough and going to far with the adjustment
Designers Push adjustment to the extreme
• To see what the adjustment looks like• Can easily see what is not wanted• Can make it easier to make adjustments
Adobe Photoshop CS5 - Illustrated
Using the Brightness/Contrast Adjustment
Adobe Photoshop CS5 - Illustrated
Before and after the adjustment
Increasing the brightness
Adjusting Black and White Points with Levels
Start and end of the image tonal range Black point
• Represents darkest image pixel White point
• Represents brightest image pixel
Adobe Photoshop CS5 - Illustrated
Adjusting Black and White Points with Levels
Black and white points Have substantial effect on contrast
Cameras set to capture image without making too many shadows or highlights that are too white Results provide a smooth tonal range Image still lacks contrast
Adobe Photoshop CS5 - Illustrated
Adjusting Black and White Points with Levels
The Levels adjustment Fixes shadows: not
dark enough Fixes highlights: not
quite white enough Histogram component
• Adjusts image by manipulating sliders at the bottom
Adobe Photoshop CS5 - Illustrated
Levels adjustment options on the Adjustments panel
Adjusting Black and White Points with Levels
Adobe Photoshop CS5 - Illustrated
Adjustments panel with Levels adjustment layer settings
Adjusting the black and white points
Adjusting the Midpoint with Levels
Midpoint Defines areas of image falling into the
available grayscale range middle
Moving the midpoint lightens or darkens the image Start at the outside and work inwards
• Set black and white points: the extremes Verify satisfactory contrast between
highlight and shadow range Midpoint can be adjusted
Adobe Photoshop CS5 - Illustrated
Adjusting the Midpoint with Levels
Adjustment layer creation Created automatically with a layer mask
• Like the Levels adjustment
Layer mask Applies adjustment selectively in different
strengths to different areas of artwork
Adobe Photoshop CS5 - Illustrated
Adjusting the Midpoint with Levels
Adobe Photoshop CS5 - Illustrated
Masking areas of the image from the adjustment
Brightening the midtones
Investigating an RGB Image
Monitors display color as lightRed, green, blue: additive primary colors of light Combine to produce all other colors in
the spectrum Mixing varying strengths produce
yellows, purples, limes, etc. RGB: like grayscale
• Various shades available per pixel• 256 shades of red, green, and blue
Adobe Photoshop CS5 - Illustrated
Investigating an RGB Image
Color printing Use cyan, magenta and yellow inks plus
black for detail (CMYK) Different than primary colors for viewing
with a monitor: red, green and blue
Cyan, magenta, and yellow Each created by removing on the
additive RGB primary colors
Photoshop’s color adjustment dialog boxes use RGB and CMY as basis
Adobe Photoshop CS5 - Illustrated
Investigating an RGB Image
Adobe Photoshop CS5 - Illustrated
Viewing the Red channel only
Viewing the image with no red component
Viewing the image with no blue component
Using the Color Balance Adjustment
Color Balance Adjustment controlling balance of red,
green and blue in an image Digital camera images often too red
• Fixed using the Color Balance adjustment
Adobe Photoshop CS5 - Illustrated
Using the Color Balance Adjustment
Pixel’s red component number Substantially greater than green and blue
number will have a red hue
If numbers for red, green and blue colors are close in value: Pixel becomes neutral in color
If numbers are the same: Pixel will have no color Can only be a neutral gray
Adobe Photoshop CS5 - Illustrated
Using the Color Balance Adjustment
Adobe Photoshop CS5 - Illustrated
Color Balance adjustment
Before and after the adjustment
Using the Vibrance Adjustment
Vibrance adjustment Useful for quickly making colors in an
image more vibrant Vibrance
• Refers to intensity of a color Measure of a pixel’s vibrance
• Called saturation• High saturation produces vibrant color• Reduced saturation produces dull, more
neutral color• Pixel with no saturation: neutral gray
Adobe Photoshop CS5 - Illustrated
Using the Vibrance Adjustment
Vibrance Adjustment settings Saturation
• Increases or decreases saturation value of all pixels selected
Vibrancy• Increases saturation of pixels needing it • Does not affect pixels already saturated
Adobe Photoshop CS5 - Illustrated
Using the Vibrance Adjustment
Adobe Photoshop CS5 - Illustrated
Over saturating the image
Before and after the adjustment
Summary
Photoshop offers practical operations Improve characteristics of images
• Color, contrast, overall effect Analyzing image appearance first step
• Image highlights, shadows, midtones Digital image
• Illusion of continuous tone
Black point: darkest pixel in the imageWhite point: brightest pixel in image
Adobe Photoshop CS5 - Illustrated
Summary
Levels adjustment Fixes shadows not dark enough Fixes highlights not quite white enough
Color Balance Adjustment controlling image balance of
red, green and blue
Vibrance adjustment Provides a setting for saturation and
vibrancy
Adobe Photoshop CS5 - Illustrated