Sign up now! · Forgot password?
RSS/Atom feed Twitter

what is dpi, ppi and lpi

This discussion is connected to the gimp-user-list.gnome.org mailing list which is provided by the GIMP developers and not related to gimpusers.com.

4 of 4 messages available
Toggle history

Please log in to manage your subscriptions.

what is dpi, ppi and lpi Amit Mukherjee 12 Apr 07:54
  what is dpi, ppi and lpi Jon Winters 12 Apr 16:19
   what is dpi, ppi and lpi Roland Roberts 12 Apr 17:44
   what is dpi, ppi and lpi Guillermo S. Romero / Familia Romero 12 Apr 19:22
Amit Mukherjee
2002-04-12 07:54:22 UTC (almost 17 years ago)

what is dpi, ppi and lpi

Hi,
Can anyone tell me the difference between dpi, ppi and lpi ? If my intention is to print a picture measuring 8"x10", at what resolution should I scan ?

Thanks Amit

Get fast and easy Internet access through http://www.netkracker.com

Jon Winters
2002-04-12 16:19:27 UTC (almost 17 years ago)

what is dpi, ppi and lpi

On Fri, 12 Apr 2002, Amit Mukherjee wrote:

Hi,
Can anyone tell me the difference between dpi, ppi and lpi ? If my intention is to print a picture measuring 8"x10", at what resolution should I scan ?

dpi = dots per inch
ppi = pixels per inch
lpi = lines per inch

to know the minimum you need to scan you'll need to know what sort of dpi your printer is capable of printing.

Lets say its an ink-jet that'll handle 1000dpi To print an 8x10 without having to scale the image up or down to make it fit you'll need to scan...

8000 x 10,000 pixels!

Pretty easy eh?

Depending on the software you're printing with you might be able to get a decent print from less. If you're going to be retouching the scan you might want to scan at double or triple the resolution of your printer so you can make really fine corrections and then scale the image down to the maximum size your printer can handle right before you print.

Enjoy!

Roland Roberts
2002-04-12 17:44:58 UTC (almost 17 years ago)

what is dpi, ppi and lpi

"Jon" == Jon Winters writes:

Jon> On Fri, 12 Apr 2002, Amit Mukherjee wrote: >> Hi,
>> Can anyone tell me the difference between dpi, ppi and >> lpi ? If my intention is to print a picture measuring >> 8"x10", at what resolution should I scan ?

Jon> dpi = dots per inch Jon> ppi = pixels per inch
Jon> lpi = lines per inch

DPI is normally used for scanners, printers, and monitors. LPI is normally used for half-tone screened images. A 100 LPI half-tone image corresponds to a much higher DPI rating.

Jon> to know the minimum you need to scan you'll need to know what Jon> sort of dpi your printer is capable of printing.

Jon> Lets say its an ink-jet that'll handle 1000dpi To print an Jon> 8x10 without having to scale the image up or down to make it Jon> fit you'll need to scan...

Jon> 8000 x 10,000 pixels!

Jon> Pretty easy eh?

For most practical purposes, 300dpi for a color print is more than good enough. Scaling the image to fill whatever resolution you need for your printer should cause no problems. If you have a 300dpi image (at print scale), and produce a fiery from it, you will be completely happy with the results. For photographs, I typically scan the 35mm negatives at 2400dpi and print up to 8x12 with no perceptible loss.

roland

Guillermo S. Romero / Familia Romero
2002-04-12 19:22:03 UTC (almost 17 years ago)

what is dpi, ppi and lpi

winters@obscurasite.com (2002-04-12 at 0919.27 -0500):

Can anyone tell me the difference between dpi, ppi and lpi ? If my intention is to print a picture measuring 8"x10", at what resolution should I scan ?

dpi = dots per inch

This causes confusion, some file formats say DPI, and monitors too... but IMHO they should say PPI. Dots per inch, but what kind of dots? Multilevel ones like pixels? Single level like ink jets? Single level but mix capable like dye based printers (so multilevel)?

ppi = pixels per inch

What monitors and files have.

lpi = lines per inch

Or how many different lines of a set of shades you can have per inch with a halftoning printer (newspapers, laser printers, normal ink jets). The more shades (b&w, 16 grays...) you want the less lines you can paint (the less fine the detail is), but more intensity levels avaliable (always supposing same printer).

to know the minimum you need to scan you'll need to know what sort of dpi your printer is capable of printing.

...

8000 x 10,000 pixels!

Umm, eeeeeek! The guys I know work at 300-400 DPI and A4 (210 * 297 mm) output, that gives around 3300 * 4700 pixels, less than 8000 * 10000. And they do not use home printers, but professional machines with good inks and papers. For home ones I guess 200-300 is more than enough, and that means 2400 * 3300 for a full 8*10, so check what size the original is, and scan so you get that many pixels.

Pretty easy eh?

It is not. You will always find problems, due inexperience, not fixed definitions or whatever. Some references are http://www.aim-dtp.net/ and http://desktoppub.about.com/library/weekly/aa101800a.htm, in this last one they already say that terms are mixed, and they add SPI (samples, about scanners, normally called DPI or PPI, being PPI the most near, cos a "pixel is sample", IMO).

OK, I think I made it even more confusing now. :]

GSR