DPI :]
Thursday, February 19, 2009 // 2:20 PM
Resolution you typically use for print 300 DPI (dots per inch)
72 DPI (FAST) for computers (internet) (dots per inch)
a million pixels is a megapixel
4 by 6 inches is the most common size for photographs
only time you use a large DPI (e.g. 1200dpi) is for something like scanning a tiny picture and blowing it up later.
a comparison in sizes could be that a 300dpi picture could be as much as 4mb while a 72 dpi could be about 500 kb. A low resolution picture would be even less.
If you retrieve an image from the internet and you want to increase the dpi and the overall quality, something you must know, is that you will never have the same quality as the original image before compression, was. This is because when an image compresses, it loses information as it throws it out in order to lessen the size of the image. The information lost can never be recovered, even when you go back in the compressed photo and try to increase the dpi. It will look better if you increase the dpi but definitely not the same as the original.
A Jpeg is a file format. it is a way to save picture information. Jpeg loses information from the pixels thus earning the name "lossy". It gets rid of unnecessary info. Good because everyone can use.
Lost-less are file names such as .psd which saves every piece of information. (no information is taken away). PSDs are good but not everyone can read this and it is a huge file.
tif. tagged image format. lost-less typically.
bmp: bitmap. lost-less.
Labels: dots per inch, jpeg, photoshop, pixel, psd, resolution