North Texas PC User’s Group Photoshop SIG Hillary Morgan Ferrer Session 3 - August 18, 2007.

North Texas PC User’s Group

Photoshop SIGHillary Morgan Ferrer

Session 3 - August 18, 2007

What we will cover today

Color Theory Histograms Exposure Correcting for Exposure Correcting for Color

COLOR

Color Theory

The Color Wheel Really Young Girls

Can Become Mothers

Boys make really young girls cry

To take out x you add y

Color Opposites

To take out Red, add Cyan

To take out Green, add Magenta

To take out Blue, add Yellow

And Vice Versa (examples in PS)

Ways to Manipulate Color in Photoshop

Levels Curves Hue/saturation Selective Color Color Balance Photo Filters Channel Mixer

How Photoshop sees Color

Photoshop sees color in terms of numbers

These numbers are graphed onto a graph called a “histogram”

8 bits = 256 shades 0 - 255 0 = black 255 = white

Histograms

For each color, you have this histogram telling you how much of which shade of each color the picture contains.

The colors exist in something called “Channels”

RBG, CMYK

Normal Histogram

No excess of bright whites

No excess of Dark Darks

Bright White Histogram

Picture is predominantly white, so we see a predominant number of pixels on the right side of the histogram

Dark Histogram

Picture predominantly black, so we see a predominant number of pixels on the dark end

Correcting Exposure

Levels– Slide on RGB scale– Slide on R,G,B scale– Black point, white point droppers– Finding Black/White points with alt– Shifting midtones

Correcting Exposure

Curves– Overall darken/lighten– Contrast curve

Over/Under

Over/Under Corrected

White Balance

Makes Colors Neutral Bright Sun, Cloudy, Open Shade, Tungsten,

Flash, Strobe, Halogen MUST do before with JPG Can do post with RAW Measured in degrees Kelvin Higher the degrees, the bluer it looks Lower the degrees, the redder it looks

Light Temperatures

Open Shade/Cloudy - 6500 Direct Sunlight - 5600 Fluorescent - 3400-3800 Tungsten - 3200

Shot on Cloudy Day

Eyedroppers in Levels

Ways to neutralize color in PS

Even when color balance in camera, can still get color cast

Gray card Eye dropper in curves, levels Auto color By sight (assuming you have calibrated

monitor) Example (John roar)

Homework…