The correct resolution for prints

PhinglasPhil

Will saving my processed images at 600 dpi in PhotoShop (as opposed to 300 dpi) increase the quality of an image when printed? Any advice would be appreciated.

stcstc

nope

well thats the simple answer

you should save at the native resolution of the printer

300 - canon and hp
360 - epson

oh and it ppi, dpi is soley in the land of the printer

PhinglasPhil

stcstc... That clarifies things for me - thanks.

cnocbui

stcstc wrote: »

nope

well thats the simple answer

you should save at the native resolution of the printer

300 - canon and hp
360 - epson

oh and it ppi, dpi is soley in the land of the printer

Doesn't the 'native' resolution depend on the paper type you have selected to print to?

I have read that Canon printers have two native resolutions, 300 and 600 ppi, for plain paper and photo paper respectively.

sineadw

Nah, it's 300 or 360. Although Fire in town print at 250. It's always worth asking if you're leaving stuff in somewhere.

stcstc

You can't have 2 native resolutions in 1 inkjet printer

Fire use 2 diff res, because their prints are kind of an analogue print for want of an easier way to explain

Heebie

The "Native" resolution of an Epson printer depends on what mode it's in, and can be 1440x1440, 1440x2880, 2880x2880, 2880x5760 dpi, depending on the printer model.

You can't send it that resolution, however, because it needs to dither the output you give it to get the right colors. There are hundreds of "real" drops of ink dithered into a pattern that gives approximately the right color for the "dot" in the image that it's sent.

Other printers have other methods etc.. The Fuji Frontier, for example, has a native resolution of 303dpi, and doesn't tend to dither because it has control over the intensity of light it's throwing at colored-light-sensitive paper.

The reason things tend to hover around 300dpi, is that it's widely considered that a human eye with 20/20 vision and no color-blindness can resolve the individual dots at resolutions below 300dpi at a distance of one foot, and cannot at above 300dpi.

The further the expected viewing distance is away from the printed material, the lower you can have the resolution and expect the average person not to be able to see the individual pixels/dots (which are interchangeable as far as I'm concerned... and since I've never seen a piece of software that had "ppi" only "dpi" and "lpi" [lines per inch]) I'm not going to fuss about which is the right one to use... it's just silly.

There is probably a mathematical formula somewhere to determine the "optimal" resolution of an image based on viewing distance, but a good guideline is don't go below 300dpi on an image that you expect people to hold in their hand, or walk up close to, and I try not to go under 180dpi for large-format prints that will be looked at from a significant difference.

I also never downsample an image to a lower resolution than I have unless I know the true "native" resolution for the output medium, as I did for the Fuji Frontier when I was working with one regularly. Sending an image that's been sharpened for output of something other than the "native" resolution of a printer can cause you to get a lot of artifacting around sharpened areas because the system/printer will resample the image to it's "native" resolution before actually printing it. If it's been sent in image that is it's "native" already, it will skip this step, or perform it with a 1:1 ratio causing no effective change to the image.
Say the "native" is unknown, and my image amounts to 837dpi at the size i want to print it it.. I will leave it there instead of sampling it down to 300 or 360, if I don't know the actual output resolution.

360 is a good resolution to send to an Epson, because all it's "native" resolutions are multiples of 1440, and 1440 is 360x4, so any of the Epson's "native" resolutions are multiples of 360. (at 1440, that gives it 16 spots of color it can mix to dither a single pixel sent to it. at 2880 it has 64, and 2880x5760 it has 128, because the resolution doubles in only one direction.)

It's really complicated.. but you don't really need to think about it that much. If you have purchased a decent printer, or are printing through a company that uses a decent printer, it's going to do a good job dithering the image to give you what you're hoping for. If your sharpening filters aren't way crazy too strong, you're not going to SEE any truly adverse effects from a resample. (Well.. unless you go looking at it with a loupe)

stcstc

no the native res of epson is 360 - thats a physical limit of the head

no head has a native res as high as 1440,

1440 is the dithered output from the 360

as it doesnt print pixels in the same place on each line

Heebie

The choices in the settings dialogues for the Epson print drivers are 1440x1440, 2880x2800 and 2880x5760. Those are the actual physical resolutions used for the drops of ink that hit the paper. The resolution it can drop ink on the paper at is a function of the precision of the print head (How small a droplet it can deposit on the paper and the density at which they can be deposited, which may be 360dpi) and the precision of the stepper motors that move the print head side-to-side, and the motors that move the paper up & down in the printer. (the minimum distance the head and/or paper can be moved in any direction.)
It is not solely a function of the print head. It can also change from one print media to another, because different papers will have different wicking factors, and the ink will actually have slightly different viscosities at different temperatures, which will affect the spread and/or wicking, and affect the functional resolution. The resolution on Epson's "lustre" finish, for example, will end up being a lot higher than on Crane Museo, because Museo is an un-coated cotton rag paper, it has a lot of wicking going on.

stcstc wrote: »

no the native res of epson is 360 - thats a physical limit of the head

no head has a native res as high as 1440,

1440 is the dithered output from the 360

as it doesnt print pixels in the same place on each line

stcstc

Heebie wrote: »

The choices in the settings dialogues for the Epson print drivers are 1440x1440, 2880x2800 and 2880x5760. Those are the actual physical resolutions used for the drops of ink that hit the paper. The resolution it can drop ink on the paper at is a function of the precision of the print head (How small a droplet it can deposit on the paper and the density at which they can be deposited, which may be 360dpi) and the precision of the stepper motors that move the print head side-to-side, and the motors that move the paper up & down in the printer. (the minimum distance the head and/or paper can be moved in any direction.)
It is not solely a function of the print head. It can also change from one print media to another, because different papers will have different wicking factors, and the ink will actually have slightly different viscosities at different temperatures, which will affect the spread and/or wicking, and affect the functional resolution. The resolution on Epson's "lustre" finish, for example, will end up being a lot higher than on Crane Museo, because Museo is an un-coated cotton rag paper, it has a lot of wicking going on.

yep thats all true, but its not the native resolution

my wide formats do 360/720/1440 and 2880

but the native res is 360, in the same way the native res of my monitors is 1920/1200

they are fixed, the fact it dithers and doesnt print dots in the same place etc are not native, they are a bit like interpolation.

this is why the recommended print input res is 360ppi as there is not interpolation or rounding errors on the fly from the printer

you are correct that it will print at higher res. also the res has nothing to do with the media, its still printed at the same res, but a by product of the paper is the rendering of the print res, though absorption etc. the same number of dots are still printed, just some blend together etc on some papers and dont on others