Scanning and Graphics Workshop I

Graphics for the Web, Scanning and Introduction to Photoshop

Graphics Workshops

I: flatbed scanner and Photoshop basics II: slide scanner and digital camera III: Photoshop “tricks” - neat things to do

with text, graphics, and file compression IV: “Clickable” images

animated gifs and graphics “helpers”

Basic considerations of graphic-design for the Web

Intro to Web graphic file formats Scanning paper documents Intro to graphic-editing with Photoshop File conversions

Web-Graphics Basics

Basic Considerations Most common file formats are .gif

and .jpeg 8-bit color 254 colors of Netscape

http://www.killersites.com/1-design/index.html

GIFs and JPEGS

GIFs use an LZW compression algorithm and have lossless compressions (decompressed image looks just like the compressed image)

uses linear pattern recognition for run-length encoding, so horizontal regularity is greatly compressable

GIF compression

941 bytes 1000 1001

1033 1102 1147

1186 1803 6685

GIFs and JPEGs, cont.

allows transparency, animation, interlacing, etc.

GIF 89a

GIFs and JPEGs, cont.

best way to compress photographic images (continuous tone images)

JPEG

Flatbed scanners

mac and Windows 95 machines use scanner software for image

acquisition use Photoshop for image manipulation

and file conversion

Scanning

scan as “millions of colors”, even if the original image is black and white

save file as .bmp or.tiff

Photoshop

Open file work with layers use image adjustment routines to

compensate for bad scanning resize images for use on Web save images in a web formats

Saving in .GIF format

select “mode” from the menu bar select “indexed color” say “OK” to “flatten layers?” select either 8-bits/pixel or “Other” for

resolution - it’s up to you. However, because gifs are an indexed file format, the fewer colors you use, the smaller your file will be!

select “exact” or “adaptive” for the palette

click “OK” select “file”, “save as”, and be sure to

select “CompuServe GIF” in the “Save File as Format Type” box.

Saving in JPEG format

if you have more than one layer you must “flatten” the image

save as JPEG (choose jpeg in “Save File as Format Type” box)