PPI & DPI

"Dave" wrote in message

Hallo to everybody:-)

If I change the pixel dimensions of an image (enlarging it to A2 in this case) and resave it in CS at a resolution of 400 x 600 mm & 300 PPI, and the printer prints it at 180 DPI (the results are beautifull), are the end result still better then it would have been if I originally saved it on 180 PPI?

I have quite a few A2’s printed, and always save it
on a resolution of 300 PPI. Last week I asked the printer on what DPI setting he is printing it, and he said that
‘they’ (printers internationally?:-) always print on 180 DPI.

Are you talking about offset litho printers?

If you are talking about sending images to a printer for litho printing, and they are going to use a 180 dot screen, for the best results you should really have you print set at 2 * 180 dpi = 360dpi which is a preset you will see on many scanners, if you have set your image to 181dpi (for example)and the printer is screening at 180 you will get an interference pattern every 1 inch. many printers will sort this by making your images slightly out of focus so the dots are out of focus if you have your images set at 360dpi then you get a interference paters every 1/180 inch which is the same as the screen so can’t be seen.
hope that makes sence.
MOP

On Sat, 12 Feb 2005 10:45:39 GMT, "MOP" wrote:

"Dave" wrote in message

Hallo to everybody:-)

If I change the pixel dimensions of an image (enlarging it to A2 in this case) and resave it in CS at a resolution of 400 x 600 mm & 300 PPI, and the printer prints it at 180 DPI (the results are beautifull), are the end result still better then it would have been if I originally saved it on 180 PPI?

I have quite a few A2’s printed, and always save it
on a resolution of 300 PPI. Last week I asked the printer on what DPI setting he is printing it, and he said that
‘they’ (printers internationally?:-) always print on 180 DPI.

Are you talking about offset litho printers?

If you are talking about sending images to a printer for litho printing, and they are going to use a 180 dot screen, for the best results you should really have you print set at 2 * 180 dpi = 360dpi which is a preset you will see on many scanners, if you have set your image to 181dpi (for example)and the printer is screening at 180 you will get an interference pattern every 1 inch. many printers will sort this by making your images slightly out of focus so the dots are out of focus if you have your images set at 360dpi then you get a interference paters every 1/180 inch which is the same as the screen so can’t be seen.
hope that makes sence.
MOP

Thanks a lot for your reply, MOP. And yes, (I think:-) your guess about litho printers are correct.

Your explanation makes a lot of sense. Does the printer saves ink by printing it on a lower resolution, and if yes, is that not the general practise? Because 99.99% of the clients do know nothing about resolution and therefore do not ask this kind of questions?

What then is the resolution I am suppose to save at? I go for 300 PPI and if I understand you correct, it must be printed at at exactly the same resolution.

Sorry for a English that is not really dictionary English. It is not my home language:-)

Dave

"Dave" wrote in message

On Sat, 12 Feb 2005 10:45:39 GMT, "MOP" wrote:

"Dave" wrote in message

Hallo to everybody:-)

If I change the pixel dimensions of an image (enlarging it to A2 in this case) and resave it in CS at a resolution of 400 x 600 mm & 300 PPI, and the printer prints it at 180 DPI (the results are beautifull), are the end result still better then it would have been if I originally saved it on 180 PPI?

I have quite a few A2’s printed, and always save it
on a resolution of 300 PPI. Last week I asked the printer on what DPI setting he is printing it, and he said that
‘they’ (printers internationally?:-) always print on 180 DPI.

Are you talking about offset litho printers?

If you are talking about sending images to a printer for litho printing, and
they are going to use a 180 dot screen, for the best results you should really have you print set at 2 * 180 dpi = 360dpi which is a preset you will
see on many scanners, if you have set your image to 181dpi (for example)and
the printer is screening at 180 you will get an interference pattern every 1
inch. many printers will sort this by making your images slightly out of focus so the dots are out of focus if you have your images set at 360dpi then you get a interference paters every 1/180 inch which is the same as the
screen so can’t be seen.
hope that makes sence.
MOP

Thanks a lot for your reply, MOP. And yes, (I think:-) your guess about litho printers are correct.

Your explanation makes a lot of sense. Does the printer saves ink by printing it on a lower resolution, and if yes, is that not the general practise? Because 99.99% of the clients do know nothing about resolution and therefore do not ask this kind of questions?
What then is the resolution I am suppose to save at? I go for 300 PPI and if I understand you correct, it must be printed at at exactly the same resolution.

Sorry for a English that is not really dictionary English. It is not my home language:-)

Dave

The is just the best compromise for printing on paper with thick printers ink and nothing to do with cost.
I would set your prints at 300 or better 360PPI for printing at 180 dot screen.

On Sat, 12 Feb 2005 20:28:44 +0200, Dave wrote:

Thanks a lot for your reply, MOP. And yes, (I think:-) your guess about litho printers are correct.

Your explanation makes a lot of sense. Does the printer saves ink by printing it on a lower resolution, and if yes, is that not the general practise? Because 99.99% of the clients do know nothing about resolution and therefore do not ask this kind of questions?
What then is the resolution I am suppose to save at? I go for 300 PPI and if I understand you correct, it must be printed at at exactly the same resolution.

Don’t get hung up on 3000 ppi. The ppi should be appropriate for the printer. Consequently, on a printer which uses 300, 600, 1200 etc dpi, 300 ppi is good. If you are printing out on an Epson inkjet where the native resolution is 720 dpi, then multiples or fractions of that are best (e.g. 360 ppi or 1440 ppi).

What MOP says about professional printing is correct. If they are using 180 then you should be using 360ppi.

Sorry for a English that is not really dictionary English. It is not my home language:-)

No problem 🙂

Dave, the reason is that because as images are printed larger, the viewing distance at which you view the image increases. Consequently, you can use a lower dpi and get the same result as if you had printed a smaller image at a higher dpi. Other than that, listen to MOP, he/she is correct.

—

Hecate – The Real One

veni, vidi, reliqui

On Sun, 13 Feb 2005 01:04:07 +0000, Hecate wrote:

The is just the best compromise for printing on paper with thick printers ink and nothing to do with cost.
I would set your prints at 300 or better 360PPI for printing at 180 dot screen.

Dave, the reason is that because as images are printed larger, the viewing distance at which you view the image increases. Consequently, you can use a lower dpi and get the same result as if you had printed a smaller image at a higher dpi. Other than that, listen to MOP, he/she is correct.

—

Hecate – The Real One

veni, vidi, reliqui

Thanks a lot for the info, MOP & Hecate.
I’m a little bit brighter now:-) (even after
learning today that the printer usually doing
my work uses a lesser value paper and that I must
start making use of the (other) printer’s services who pointed it out to me:-)

Dave
(would have added my website url here,
if only I could remember it:-)