Four-color process is a printing process that uses four colors of ink, Cyan. Magenta, Yellow and Black to achieve an optical range of thousands of colors.
The creation of halftone dots for reproducing optical values or shades of a single color of ink in a printed piece is a process called "halftoning". By varying the size or density of dots, the eye can see a shade somewhere between the solid color and the color of
the background paper. This halftone effect has its lmits for when the dots get too small or spaced too far apart the eye can start seeing the individual dots, such as in newpaper printing.
It depends on the final output. Will it be for print reproduction (CMYK) or for display on a computer monitor or video display (RGB). If your client has a limited budget, you might just have to work with spot colors, which don't exactly fit into either catorgory. See below.
Switching from RGB to CMYK will generally lose color information (the colors will become grayer), however, coverting a CMYK image to RGB will display no noticable shifts in color. The reason for these changes is RGB is a much bigger color space or color gamut.
Spot colors are specially mixed inks that come in a rainbow of colors, including some speciality inks such as metallic and flourescent. Unlike CMYK or process color which creates colors by laying down layers or millions of dots of cyan, magenta, yellow, and black in varying amounts on the printed page, spot colors are pre-mixed and applied individually to the printed page.
Each spot color requires its own plate on the printing press. Because a varnish requires a separate plate it is considered a spot color, too.
If you are planning to print an image with spot colors, you need to create spot channels(Photoshop) to store the colors. To export spot channels, save the file in DCS 2.0 format or PDF.
Spot colors are overprinted on top of the fully composited image. Each spot color is overprinted in the order it appears in the Channels palette (Photoshop).
Well, the best answer I can give is, "It depends." It depends what you plan to do with the image, is it for print, on a printing press, a proofing device, or a large-format printer, or is it intended for screen display? The answer to the latter question is generally 72 ppi.
Photoshop's Image Size Dialog Box
Explanation of upsizing and downsizing images
Learn the five basic rules for working with Bezier curves.
General sketching exercises your hand-eye coordination. It is also a valuable aid to help you better observe the world as an artist sees it.
Thumbnail sketching, used to work out your concepts before sitting at the computer, will not only save you from wasting time at the computer but you need to develop the skill of thinking-with-your-pencil.
"Pencils before pixels" - Dermot MacCormack
In this business of design, ideas are what sells.
You need to develop your idea gneration skills and
putting your thoughts down on paper quickly will make you a valuable asset to your employer.
Computer skills are an asset, but ideas/concepts are more important!
Thinkertoys: A Handbook of Creative-Thinking Techniques by Michael Michalko
Cracking Creativity: The Secrets of Creative Genius by Michael Michalko
Lateral Thinking: Creativity Step by Step by Edward de Bono
Six Thinking Hats by Edward de Bono
Caffeine for the Creative Mind: 250 Exercises to Wake Up Your Brain by Stefan Mumaw and Wendy Lee
A Whack on the Side of the Head: How You Can Be More Creative by Roger von Oech
Creative Whack Pack (a card game) by Roger Von Oech
Creative Sparks: An Index of 150+ Concepts, Images and Exercises to Ignite Your Design Ingenuity by Jim Krause
Thinking Creatively by Robin Landa
OR try some of the suggestions at the right.
Brainstorming – Create a tsunami of possibilities!
Free association – Just let it flow!
Journaling – Mind and hand working together. Almost as good as drawing!
Mind Maps
What are they? (Wikipedia)
Tony Buzan on Mind Mapping (YouTube)
MindTools.com
Creativity Tools (MindTools.com)
Group Play – Don't get the wrong idea here!
What is a morgue or swipe file?
It's simply a collection of images or reference materials you save to a file cabinet, either paper or digital.
Many artist and designers keep such files for ideas and to be inspired creatively by image they respond to strongly.
What is a Morgue file? (ArtSlam.com)