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Photoshop. Basic Theory. Bitmap vs Vector. Bitmap based on pixels Pixel is the smallest element of a bitmap Used in Photoshop Change in size changes quality Vector based on mathematical formula Used in Illustrator Change in size does not affect quality. Bitmap. Measured in pixels
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Photoshop Basic Theory
Bitmap vs Vector • Bitmap based on pixels • Pixel is the smallest element of a bitmap • Used in Photoshop • Change in size changes quality • Vector based on mathematical formula • Used in Illustrator • Change in size does not affect quality
Bitmap • Measured in pixels • Bit-depth is the amount of digital storage space used to record information about the color of a pixel • 24 bit scan with 256 gray levels • 24 bit monitor with 16 million colors
Pixel • Short for picture element • Smallest element of a bitmap • In Photoshop you edit pixel information • Change color • Change shade • Change brightness
Resolution • Measured in pixels per inch (ppi) • Pixel size varies based on resolution • 100 ppi : 1 pixel = 1/100 of an inch square • 300 ppi : 1 pixel = 1/300 of an inch square • Dragging a corner and changing size does not change the number of pixels • Printer resolution is not the same as image resolution
Color Models • RGB – Red Green Blue • Mirrors the way a human eye sees color • Used in scanners, digital cameras, and monitors • RGB are the “additive primaries” • 100% of Red Green Blue light = White
Color Models • CYMK – Cyan Yellow Magenta Black • Used in Printing • CYM are secondary colors • Also called the “subtractive” model • Take away all 3 when printing = white • All 3 together should make black but makes a muddy brown because of impurities • Printers add Black to make a true black
Color Gamut • The range of colors that a specific device is capable of producing • Makes the printing process complicated • Gamut of a monitor does not equal the gamut of a printer. • Some colors can’t be matched • Vibrant yellows or deep blues
Which Mode to Use • Use RGB mode if image is intended for WWW. • Use CYMK or RGB if image is intended for print but make sure you convert to CYMK before going to another program to set up printing (Illlustrator)
Color management • Several settings available in Photoshop • Edit Menu >>Color Settings • Use Web Graphics Defaults for WWW • Use US Prepress Defaults for print • Can create custom but not recommended for amateurs!