Printing photos - How do I determine resolution and dpi to print on 8.5 x 11 paper?

P

Praetorius

Limp Gawd
Joined
Jun 6, 2002
Messages
310
If I want to print a photo how do I determine what resolution and dpi the image should be converted to prior to printing?

I'm printing to a Canon i960 which has a horizontal resolution of 4800 dpi and a vertical resolution of 1200 dpi.
 
DPI is the number of dots of ink per inch, not the number of pixels. When you're printing, the resolution depends on the application. For a billboard, for example, you need much lower resolution density than for a small photo print. If you want to print an image, DO NOT (!!!!) change the resolution of it. Don't convert it, just print it.
 
Praetorius said:
If I want to print a photo how do I determine what resolution and dpi the image should be converted to prior to printing?

I'm printing to a Canon i960 which has a horizontal resolution of 4800 dpi and a vertical resolution of 1200 dpi.
Click to expand...

I'm guessing as close as you can get to 4800? :confused:

I think we need more info to answer this. Can you give the specific size you want the image to be on the page, and what's size of it + resolution?
 
Basically, here's how it works:

You've got a bunch of pixels. You can print these any size you want them. If you print them too big, it will look like shit. The only thing you need to know is whether or not it will look good at the size you want to print it, or alternatively how big you can make it before it looks like shit. You cannot change the resolution or do anything like that to improve it. All you have is the current number of pixels, and that's that.
 
Black Morty Rackham said:
DPI is the number of dots of ink per inch, not the number of pixels. When you're printing, the resolution depends on the application. For a billboard, for example, you need much lower resolution density than for a small photo print. If you want to print an image, DO NOT (!!!!) change the resolution of it. Don't convert it, just print it.
Click to expand...
+1

OP, if you are really concerned about it check some of these links. Lotsa reading but worth it.
design215.com
rideau-info.com
steves-digicams.com
 
If you're printing a photo, and the image will be printed at pretty much 1:1 scale, anything at 300dpi and above should be fine for colour, and 600dpi for greyscale. Remember though, it is pixels per inch so if you're printing a 300dpi pic at 200% size on paper, then effectively the printed pic is half the dpi - 150dpi (1 inch on the file equals 2 inches on the printed output) so you can get pixelation.

Always keep in mind the output size when doing any dpi conversion. It's not much point having a 4800dpi image that will be printed out at 50% actual size on a printer that can only print at 1200dpi max. Be aware that printers have a limit to what dpi they can output, so a 4800dpi image will only print out at 600dpi on a 600dpi max resolution printer and won't look any better than a 600dpi image printed the same way assuming the image is printed 1:1.

However, it is good practice to at least store a copy of the orginal image at max resolution for later reference and use.

Another thing to note. The printer prints in CMYK, however, it is not usually necessary to convert your RGB images to CMYK beforehand. Often, the printers built in conversion algorythims can yeild more vibrant results form an RGB image than a pre-converted CMYK image. But have a play and see what you like.
 
The Cannon i960 will print great photos if you use the high settings or, finest. I have one and, it has always printed great at 8x11s. Now I have a Pixma Pro9000. It prints way better pics. :D
 
Bugger! :p

Sorry, I should use ppi (pixels per inch) instead of dpi (dots per inch) when refering to onscreen images.

O.k... .here's the short short version. If an image is 300ppi, 6"x8" in photoshop and you print it out twice the size.... 12"x16" (actually 4 times the size but skip that ;) )... 1 inch in the file is printing as 2 inches on the paper, therefore, you're only getting 150 pixels per inch instead of 300 pixles per inch.... so pixelation will start to occur.

You can simulate this onscreen. Get an image in photoshop and zoom up close. The bigger the scaling from the original, the more pixelation you see onscreen. Exactly the same as if you print out the image at a larger scale on paper.

Hope that makes sence, makes sence to me anyway ;)

Dpi or dots per inch is how many ink splots your printer will make per inch. If it can only do 300 ink splots per inch, you will not achieve any better result having a 600ppi image over a 300ppi image unless you are scaling it.

A side note, if you're preparing images for commercial printing (offset or what-ever) as a general rule-of-thumb in pre-press, an image ppi should be twice the lpi (lines per inch). i.e., an image that is to be printed at 120lpi should be 240ppi in the file. There will be no pixelation and there is no point having a higher res image.

I have a Canon PIXMA iP5200 which prints great photos. I usually use 300ppi images. Make sure if you save your pics as JPG you use the highest quality compression.
 
We've got a print here at the office that's about three meters wide. It's about 25 PPI, and looks great. Horrible up close, obviously, but stunning from only a couple of meters away.
 
Black Morty Rackham said:
We've got a print here at the office that's about three meters wide. It's about 25 PPI, and looks great. Horrible up close, obviously, but stunning from only a couple of meters away.
Click to expand...

Yeah, large posters and banners are usually around 32ppi as they are viewed from far away.... otherwise, the files would be huge. I have some mates that work for a company that did the Lord of the Rings Aeroplane graphics, and even at a low ppi they were working with 4GB files :eek:
 
You must log in or register to reply here.
Back
Top