does dpi and ppi are the same? how to save a hi-res JPG image(dpi must over 300) since the ppi is 400 already

Answer 1

If you are talking about saving the image at a specific resolution, then you are going to want to save it at 300 ppi or better. If you are talking about printing, then you want to print the image at 300 dpi or better. They are two different things that people interchange a lot without realizing it.

DPI is dots per inch. Basically, it's how much ink used per inch of image space to print. The higher this number the smoother and more seamless your image looks.

PPI is pixels per inch. This is how many little dots of color your computer needs per inch to create the photo digitally. Again, the higher this is, the more seamless the photo and the sharper the image.

If you are being told to save it as 300 dpi, chances are that it's fine the way it is. But, I'd ask your teacher just to be sure.

Answer 2

"Brad H" does not, quite have it right. They are NOT, essentially the same thing.

A pixel is, simplly a single element in the content of a digital image. It is one, square, solid color, otherwise featureless. Put a bunch of pixels together and you have an image, much like a tile mosaic. The more pixels, the greater detail is in the image. A pixel has no specific size. A pixel can be, either, large or small.

A "dot" is a tiny spot of ink, applied to a printer. The more dots that the printer can apply in a given space, the more detail can be shown in the print. If a low digital image is to be enlarged, and then printed, the printer may take many dots to create one pixel. In traditional CMYK colors, more than one dot is REQUIRED to create most colors. So, a blue pixel will have to be made of a certain amount of cyan, red, and black ink dots. A tiny, web image, such as the Yahoo avatars, blown up to 8 x 10 paper will, actually contain several hundred ink dots, just to recreate a SINGLE PIXEL.

One more thing, even the dots per inch figure, associated with a printer is not an indicator of detail quality. A more significant figure is the printer's line screen capability. It is a pity that manufacturers do not publish that figure as prominently as it's dpi.

Answer 3

DPI= dot per inch
PPI= pixels per inch
DPI refers to printers
PPI refers to display monitors.
They are essentially the same thing because a pixel is just a dot. They are just different because it depends on the equipment your talking about.

Answer 4

They are not the same, but I think that it is probably only nit-picking.

I think that the image is ready.