Distribution Considerations TA4 Flashcards
What’s dpi or ppi
Dot per inch
Pixel per inch
Compression
Making large files smaller.
Making easier to store and send
Lossy compression
Permanently deleting part of a file to make it smaller, can’t be undone
Commonly on audio & image eg. JPEG image files
Why is lossy compression bad
Lower quality of image eg. Pixilated it
Advantage of lossy compression
File sizes reduced more then lossless
Disadvantages of lossy compression
Are lower quality,
Can’t be restored to their original high quality
Lossless compression
Making files smaller but don’t loose any data , can’t be decompressed back to original
Advantage of lossless compression
Files can be decompressed back to original quality, no data lost
Disadvantages of lossless compression
File sizes are generally larger than lossy compression
What does compression help with
Helps transmission speed across a network and in saving storage
What are bitmap images like
Pixilated coloured square that is stored as a number.
What are vector images like
Have straight lines by coordinates
How do we see number of pixels
Pixel dimensions
Dots per inch (or pixels per inch)
What does higher pixel dimensions mean
Better quality image
What’s a TIFF file
(Raster file format) A lossless compressed file, used for high quality printing or scanning.
Very high quality for photography or desktop publishing
(Doesn’t compress as effectively, lead to large files size)
What’s a JPEG file
(Raster file format) Lossy compressed file commonly for online photography and artwork, low quality printing
Compress images a lot, useful display on websites.
Has pixilation dues to lossy compression
What’s a GIF file
(Raster file format) Lossless compressed file
Commonly used simple web graphics/ embedding animations
Small file size due to lower colour depth (means can only display 256 colours)
What’s a PNG file
(Raster file format) Lossless compressed file
Used for high quality images that require transparency
Has colour depth, having control over quality vs. File size
What’s a SVG file
(Vector file format)
Can be compressed, used for web
Supports animation effects / colours changing
What is eps
(Vector file format) Excellent compatibly with graphic design software and printers
Outdated doesn’t compatible with web , poor compression ability
What is pdf file
(Vector file format) uses compression used for printing, docs on webs
Can contain raster image data
Can be small file size
Vector file format
Images built by math coordinates
Eg. PDF, svg
Raster data format
Boxes / pixels equally sized on rows
Eg. JPEG
