Dpi Help

[francesjoy]

Hi, I have to take a photograph put it into photoshop for editing and then bring it into quark for my college project, on the brief it says we have to set the photo res to 300DPI, we havent covered this in class and now i am really stuck, please, please, please help.
Fran

[dave milbut]

image> image size. uncheck the "resample image" box and set the PPI to 300.

[francesjoy]

Hi Dave

Thanks but one more question.

PPI is that the resolution box/ pixels inch.

Sorry probably sound a bit stupid but totally new too all this

Thanks Fran

[Colin Walls]

That's it Fran.

[dave milbut]

yes. pixels per inch. photoshop doesn't work in dpi (dots per inch) that's a printer term. ppi is a screen (monitor) term.

[Daryl Pritchard]

Fran,

Just to add a bit of clarification, many folks interchangeably use the terms "DPI" and "PPI" in reference to image resolution. "PPI" (pixels per inch) is considered the more correct term, since it directly relates to the physical dimensions of an image. Meanwhile, "DPI" (dots per inch) is printer terminology that is talking of how many dots of ink are laid down per inch of printed media. It helps to understand the difference when you start printing, for example, a 300 PPI image at 1200 DPI. What this particular example means is that the printer is capable of dithering up to 4 dots of ink per pixel of image data, thus providing what appears to be a more continuous tone image. Conversely, if you were printing at 300 DPI, then the ink is laid down more coarsely and you could in essence think of it as providing one dot of ink per pixel of image data. Now I'll add this isn't exactly correct, due to dithering characteristics of various printers, the ink absorption characteristics of different print media, etc., but it sufficiently describes the basic concept that I think it can be more easily remembered.

Regards,

Daryl

[francesjoy]

thanks

was changing the resolution box to 300 but not unchecking the resample image box and the file was going from 883kb to 6.5mb guessed it was wrong, why would you use it checked when the quality seems to be the same. thanks you are a babe
Fran

[Daryl Pritchard]

Uh, yeah, what Dave said. :) Isn't cross-posting fun?

[dave milbut]

sure daryl, but yours was in english! :)

fran you leave it checked when you want to resize an image, ie make it larger or smaller by adding or removing pixel data. that's known as resampling. you un-check it when you just want to change the resolution, say, for printing, without changing the actual pixels. (72 ppi is fine for viewing on screen, but most times 300ppi is a better setting for the printer).

[Bill Lamp]

Frances,

You will need to get a handle on resolution. I call it, as a joke, learning the DPI is not DPI is not DPI.

For the same picture, you could say you scanned it at 2900x2900 DPI (scanner resolution), edited it at 96 DPI (actually Pixels Per Inch and the true figure will depend on your monitor AND its settings), set the file to 300 DPI (lines per inch) and printed it at 2880 x 1440 (printer ink resolution - again not quite right but understandable)

The best place I know of to work this out is at [url]www.scantips.com[/url]. There is a free to use online book that has a very good explanation of the various resolutions.

I said you had to learn it...well for a one time thing, perhaps not. But if you get into graphics, you will need to know what is going on with all those various numbers and just what they mean. THAT was, for me, the hardest part of getting properly started. That site cleared it up.

Bill