4. PPI = (pixels per inch) refers to screen resolution
DPI = (dots per inch) refers to print resolution
The two are interchangeable
Often images are referred to as high resolution (hi-res) or low resolution
(low-res).
High resolution would be an image intended for print, generally having
300 dpi or more.
Low resolution refers to images only intended for screen display, generally
having 72 - 150 dpi.
5. Image enlarged so that you can see the individual pixels, each pixel is a
solid square of colour.
6. Standard screen resolution is 72 dpi and standard print resolution is 300 dpi
Circle at 72 dpi enlarged to see individual pixels
7. Standard screen resolution is 72 dpi and standard print resolution is 300 dpi
Same circle at 300 dpi enlarged to see individual pixels
10. Raster (Bitmap)
• Made of pixels; tiny dots or squares* of colour
• Represents and edits photo and photo-like elements
better than vector programs with the use of
continuous tones. The use of different colour pixels
allows for smooth blends of colours.
Disadvantages
• Is bound by the number of pixels in the image. It
cannot be scaled up without losing quality.
•Large (dimension) & detailed images equal large file
size
• Some service providers like engravers, stencil-cut
signs, etc, must have vector art.
• It is more difficult to print raster images using a
limited amount of spot colors
• Depending on the complexity of the image,
conversion to vector may be time consuming
11. Vector
• Made of mathematical calculations that form
objects and lines
• Can be scaled to any size without losing quality
• Resolution-independent: Can be printed at any
resolution
• Number of colours can be easily increased or
reduced to adjust printing budget.
• A large dimension vector graphic can maintain
a small file size.
• Vector art is required by many service
providers
• Can be easily converted to raster
Disadvantages
• It is not the best format for photographs or
photo-like elements with blends of colour
12. Image scaled 600%
On the left the vector image is still sharp
But
On the left the bitmap image is blurry
14. All jpg’s are Bitmap or Raster images,
they are made from a mosaic of pixels
jpg file
Characteristics of a jpg file:
• Small file size - compressed file format,
makes the original file a smaller files size
due to lossy compression.
• Smooth gradients like are found in a
typical photograph
• Be careful not to over compress a jpg file
picture Fran Jackson
15. Too much jpg compression will distort your image
jpg distortion
picture Fran Jackson
16. RAW is not an acronym for anything, is simply is the raw unprocessed data from your image sensor
17. JPEG = Joint Photographic Experts Group, nowadays shortened to jpg or JPG
23. Vector is a series of lines filled with colour, it is created by the computer.
Therefore the computer is able to manipulate it’s size and properties
easily and without loosing any quality or edge definition
Vector graphics generally have simple outlines and solid colour fill
Vector graphics are small file size also, they are not good for complex images
Vector graphics are commonly used for things like logos
24. All text in Photoshop is vector
Tools like the shape tool can be used in a vector mode or a bitmap mode
Just make sure you choose the shape layer mode for vector
You can’t mix vector and bitmap on the same
layer, or use bitmap tools on a vector
