Photoshop and Illustrator are both equal in there own aspects. The number one thing you must understand is Photoshop is for creating and editing photograph type material and Illustrator is for creating and editing print type material.
Q: What is the difference between Photoshop and Illustator?
A: This is a very important question and you must understand before you put a lot of time into a logo or hire someone to do one for you.
Photoshop - is a "bitmap" image processing and manipulation program. It's ideally suited for creating, modifying and outputting digital images of a photographic nature, which share a common fundamental structure: pixels in a bitmap. Simplified, but primary operations would be:
• Access / manipulation of digital graphics photographic in nature
• Add, subtract, modify, colorize, pixels in the images
• Produce digital files where the whole image is part of a "fixed" pixel structure (the "bitmap")
• Prepare complicated color/BW images for further processing in page layout programs for high resolution printing
Fundamental difference: Photoshop manipulates individual color pixels within a fixed bitmap
Illustrator - Illustrator is a vector-based postscript drawing program. Its used to create high quality print material. It functions by generating curved paths (Bezier curves) connected by modifiable anchor points. These anchors, with their handles are ultimately editable, and never "leave" the structure of the file.
A vector based drawing program creates the various elements of the image as individual vector objects which retain their characteristics and do not become part of a "bitmap".
Create complicated graphics like:
• Menus, etc.
Fundamental difference: Illustrator generates "vector objects" which are not part of a "bitmap"
Sample: Here is a logo that I helped someone in the forums with recently:
When you create an image in Photoshop and then try to make it bigger, it will blur because of the pixels. Now Illustrator uses mathmatical calculations, so no matter how big you make your image it will always be clean and crisp.
Bottomline - If you are only creating a logo for your web site and will never do any type of print, then photoshop works great and you can create some pretty cool effects. If your are planning on using your logo for both web and print then most experts should recommend using a vector program like Illustrator or Corel Draw.