Week Six: Review Questions

Kathryn Fletcher, kfletche.geo@yahoo.com 

1.On the Web, the intensity of each of the primary colors is assigned a number from 0 to  ____ 
255
2. The ________ image format is normally more suitable for photographs. 
JPEG
3. The use of the ________ Palette guarantees that an image will be displayed in browsers without dithering. 
The Safety palette made up of the 216 web-safe colors. 
4. Discuss the differences between the GIF and JPG formats. When should one be used over the other?  
GIF does not compress the image but it is restricted to 256 colors. It is best for images with large areas of solid colors such as line drawings, charts, scanned maps, and screen snapshots. It also allows you to designate one color to be transparent - sometimes useful for images whose background color needs to be made invisible to look better against the web page background. Often, web site "buttons" should be GIF files.

JPEG allows millions of colors and will create an image with a smaller file size. Smaller files are desirable for web publications. However, the JPEG format achieves this smaller file size by compressing the image. If the image has any large areas of the same color, you will often get artifacts - some pixels will be a different color. You should also not resave a JPEG image as each time you do, you lose more information with the additional compressions being applied; always keep a copy in TIFF or PSP format. JPEG is best used for photographs which usually need lots of colors to be able to realistically reproduce the subject matter.
5. What is an image map? Describe a situation where an image map might be effectively used.  
An image map is an image with some areas designated as "hot spots" which act as links to other web pages. 

Situations where an image map might be effective:
6. Describe a situation where you would use a Mask. 
A Mask could be useful if you wanted to place an image on another image - it allows you to block out the background from the image to be copied. A mask can also be used to protect an area of an image from a special effect you want to apply to the rest of the image.
7. Describe a situation where you would use Layers. 
I would use Layers if I were creating an image composed of multiple elements, perhaps combining images with other images or text. By placing items on separate layers, you can manipulate each item separately (location, special effects, and/or color correction).
8. What is the advantage of saving your file in PSP format?
If you keep a copy of the file in PSP format, you can retain layers if you created any and you can keep a copy of the file with millions of colors but no compression.

Return to Kathryn's Paint Shop Pro eClass page

1