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todd2000

macrumors 68000
Original poster
Nov 14, 2005
1,624
11
Danville, VA
I've been reading about printing my images at a large size, and I've just managed to confuse my-self more :). I see people saying that for best printing my images should be 300 DPI. The pictures from my camera are only 72 DPI. Should I use Gimp or some other program to increase the DPI? I don't even think that is possible, I don't understand how just changing the DPI in a program can add pixels to the images that previously didn't exist. I have a picture that is 2816x1876 Pixels just incase it matters. According to the built in printing service in iPhoto it will print fine up to 20x30, I really only wan't to print it at 16x20. The camera that was used is 6MP. So basically to sum up my question is:

What exactally (if anything) do I have to do to my picture straight from the camera to print a nice looking large print?
 

iMeowbot

macrumors G3
Aug 30, 2003
8,634
0
Don't worry about the DPI number stamped on the image metadata.

The number you care about is how many pixels you end up when they are shrunk down (or blown up) to the size of the prints you want. If your image is 1000 pixels wide and you print it on 4-inch-wide paper, you'll get 250 pixels/inch and so on.

It's not going to help much to expand the picture with gimp or whatever, you'll only be duplicating what they would be doing anyway.
 

todd2000

macrumors 68000
Original poster
Nov 14, 2005
1,624
11
Danville, VA
Don't worry about the DPI number stamped on the image metadata.

The number you care about is how many pixels you end up when they are shrunk down (or blown up) to the size of the prints you want. If your image is 1000 pixels wide and you print it on 4-inch-wide paper, you'll get 250 pixels/inch and so on.

So basically following your logic my picture can only be printed at 300DPI up to 6x9, thats not very large:confused: I printed a few 8x10s from images that were 1600x1200, which if I follow correctly only printed at 150DPI, and they looked fine. Im still confused, what exactally is an ideal resolution for a 16x20? Or a better question, what in your opinion is the largest you can print a 6MP image 2816x2112 and still have it look good?
 

todd2000

macrumors 68000
Original poster
Nov 14, 2005
1,624
11
Danville, VA
Yeah, you've got it, that 300 DPI isn't really a realistic number for what most digital cameras are really going to let you do.



It's very subjective :/

So my 2816x1876 image will print at approx. 140DPI, whic if I follow that link you agve me right, means it should look fine from 2 feet away, and farther, and relly who sees a pic on the wall and goes to stare at it from 2" away? :)
 

iMeowbot

macrumors G3
Aug 30, 2003
8,634
0
So my 2816x1876 image will print at approx. 140DPI, whic if I follow that link you agve me right, means it should look fine from 2 feet away, and farther, and relly who sees a pic on the wall and goes to stare at it from 2" away? :)

Maybe a little less than 140, remember that the image will be cropped in one dimension to fill the paper. (117?)

But yeah, depending on where you're hanging this thing, if could look lovely or it could look like a blurry mess. As long as it's not smack in front of a desk or something, you're probably fine.
 

todd2000

macrumors 68000
Original poster
Nov 14, 2005
1,624
11
Danville, VA
Maybe a little less than 140, remember that the image will be cropped in one dimension to fill the paper. (117?)

The original image was 2816x2112, I already used the Constrain menu in iPhoto to crop it down to 16x20, which ended up being 2816x1876, so it shouldn't have to be cropped any further right? Which should mean It will print at 140DPI I think.
 

ChrisA

macrumors G5
Jan 5, 2006
12,828
2,033
Redondo Beach, California
So basically following your logic my picture can only be printed at 300DPI up to 6x9, thats not very large:confused: I printed a few 8x10s from images that were 1600x1200, which if I follow correctly only printed at 150DPI, and they looked fine. Im still confused, what exactally is an ideal resolution for a 16x20? Or a better question, what in your opinion is the largest you can print a 6MP image 2816x2112 and still have it look good?

It depends on how critical of an eye you have and also on the viewing distance. Let's start with a viewing distance of "hand held". When looking at a snapshot or a book it will be no father then arms length. In this range you would prefer 300DPI. 250DPI is almost as good. You can go to 200 and it will not look really bad. At 150 it will loose any "snap" and crispness it might have had and many people can see pixels at 150dpi.

If you are going to display the photo ware the viewer will be more then an arms length away you can use proportionally fewer pixels. For example 150DPI is good for a 6 foot distance.

You said 150DPI worked OK for you. That's fine perhaps the image was not so sharp to begin with or you are not so demanding about image quality. 150DPi is about the quality you see printed in magazines. It's OK but not up to Fine Art standards. It all depends on your standards. When I did printing in my darkroom I'd put a 4x loupe on my final prints to check for sharpness

If you want to keep the quality to 300DPI and you have a 6MP camera then you can print up to about 10 inches wide. You can push it up to 14 inches if you want. For really large prints use film. Film will give you about four times the resolution as a 6MP digital camera. 35mm Film is about like having a 24MP camera. Or on the "other side of the coin" -- a 6MP DSLR camera captures only 1/4 of the information a 35mm film camera captures

My next camera will be a 4x5 large format system.
 

iMeowbot

macrumors G3
Aug 30, 2003
8,634
0
The original image was 2816x2112, I already used the Constrain menu in iPhoto to crop it down to 16x20, which ended up being 2816x1876, so it shouldn't have to be cropped any further right? Which should mean It will print at 140DPI I think.

There could be borders that fudge this, but assuming ordinary square pixels, 2816/20 is 140.8 but 1876/16 is 117.25

The ratios are different there, 16/20 is 3/4 while 1876/2816 is 2/3.

Playing with iPhoto here, I am getting the 3/4 ratio if I use the constrain tool at 16x20. Did you maybe use the 20x30 constraint for cropping, since that was one of the sizes you were also considering?
 

ChrisA

macrumors G5
Jan 5, 2006
12,828
2,033
Redondo Beach, California
Maybe a little less than 140, remember that the image will be cropped in one dimension to fill the paper. (117?)

But yeah, depending on where you're hanging this thing, if could look lovely or it could look like a blurry mess. As long as it's not smack in front of a desk or something, you're probably fine.

You can do a bit of math: From about 7 feet away the 140DPI print will look as good as a 300DPI print viewed from 3 feet
 

Abstract

macrumors Penryn
Dec 27, 2002
24,869
900
Location Location Location
To add to this thread, it depends on how sharp the photo was to begin with. If it's tack sharp, go ahead and print at 200 ppi. If it was sharp, but not TACK sharp, then a 300 ppi print will probably the same as a 200 dpi print of a sharp photo. :eek:

This is so subjective that it's killing me. Just print it, I say. Learn from your printing experiences. Just make the print you want, stand at different distances from this print, a make a mental note of how good it looks at this ppi from different distances.

And don't worry about dpi. That's a printery term. My magazine designer friend says that his magazine is printed at like 2400 dpi or something, but that he can't control this himself. He just does everything at 300 ppi and it's fine.
 

FrankieTDouglas

macrumors 68000
Mar 10, 2005
1,554
2,882
The printer is probably 2400 DPI, but the image itself is 300.

I just recently took a 6mp shot from my nikon and sized it for 16x22. I maintained 250 DPI for it so I ended up resampling the pixels in the photo to increase the resolution. And only after doing that did I apply the unsharp mask on it to regain sharpness. Printed out fine.

Just play around, if you can, and see what you prefer.
 

compuwar

macrumors 601
Oct 5, 2006
4,717
2
Northern/Central VA
I've been reading about printing my images at a large size, and I've just managed to confuse my-self more :). I see people saying that for best printing my images should be 300 DPI. The pictures from my camera are only 72 DPI. Should I use Gimp or some other program to increase the DPI? I don't even think that is possible, I don't understand how just changing the DPI in a program can add pixels to the images that previously didn't exist. I have a picture that is 2816x1876 Pixels just incase it matters. According to the built in printing service in iPhoto it will print fine up to 20x30, I really only wan't to print it at 16x20. The camera that was used is 6MP. So basically to sum up my question is:

What exactally (if anything) do I have to do to my picture straight from the camera to print a nice looking large print?

If you're printing it yourself, then you may need to upres it to get things right, but you'll be able to experiment (on smaller paper, with a portion of the image if you don't want to go broke doing it.) If some other (non-discount) place is printing it, let them handle the upres- they'll do a better job with a RIP than you'll be able to do in anything. If it's going to an inkjet at a discount place, then it'll likely be a coin toss.
 

todd2000

macrumors 68000
Original poster
Nov 14, 2005
1,624
11
Danville, VA
There could be borders that fudge this, but assuming ordinary square pixels, 2816/20 is 140.8 but 1876/16 is 117.25

The ratios are different there, 16/20 is 3/4 while 1876/2816 is 2/3.

Playing with iPhoto here, I am getting the 3/4 ratio if I use the constrain tool at 16x20. Did you maybe use the 20x30 constraint for cropping, since that was one of the sizes you were also considering?

I think your right, I did constrain it to 20x30. Does 2639x2112 sound better for a 16x20? Im not quite understanding the ratio thing though if I divide 2112/2639 I get .80 not 3/4?
 

iMeowbot

macrumors G3
Aug 30, 2003
8,634
0
I think your right, I did constrain it to 20x30. Does 2639x2112 sound better for a 16x20? Im not quite understanding the ratio thing though if I divide 2112/2639 I get .80 not 3/4?

That's fine, it should be .8, I was typing late on new year's eve :)
 

todd2000

macrumors 68000
Original poster
Nov 14, 2005
1,624
11
Danville, VA
If you're printing it yourself, then you may need to upres it to get things right, but you'll be able to experiment (on smaller paper, with a portion of the image if you don't want to go broke doing it.) If some other (non-discount) place is printing it, let them handle the upres- they'll do a better job with a RIP than you'll be able to do in anything. If it's going to an inkjet at a discount place, then it'll likely be a coin toss.

Alas the biggest I can print on my Inkjet is 8x10, what would you consider a "Non-discount" place? Is the built in printing in iPhoto (Kodak) good?

That's fine, it should be .8, I was typing late on new year's eve :)

Ahh had a bit much to drink did we? :). I think im getting this now 16/20 =.8, so as long as my picture 2112/2639 equals .80 there should be no more cropping right?
 

iMeowbot

macrumors G3
Aug 30, 2003
8,634
0
Ahh had a bit much to drink did we? :). I think im getting this now 16/20 =.8, so as long as my picture 2112/2639 equals .80 there should be no more cropping right?
Right, you have the same ratio, so it will be a neat fit. And you can get a better idea of what the real resolution will be.
 

Blue Velvet

Moderator emeritus
Jul 4, 2004
21,929
265
And don't worry about dpi. That's a printery term. My magazine designer friend says that his magazine is printed at like 2400 dpi or something, but that he can't control this himself. He just does everything at 300 ppi and it's fine.


There's some mixing of the terms. 2400 ppi is the resolving resolution of many imagesetters, much the same way a laser printer can render at 600 or 1200 dpi, although with CTP (computer to plate) processes rapidly taking over the imagesetter's days are numbered.

That fine resolution is necessary to render a clean dot, essential for good half-tone reproduction on press. However, those dots can be set at anything between 80-225 lpi depending on the stock being printed on and the speed and process of the printing process itself...

That doesn't mean that when images are half-toned that they'll need to be at 2400ppi although for reproducing sharp graphic shapes on press, say if you were rasterising type, then a minimum of 1200ppi would be suitable.

The oft-quoted 300 ppi has become a standard only for continuous-tone (i.e. greyscale or colour images) by being the usual minimum for preparing images for press. However, some fine art printing might need images at 450ppi, newspapers can get away with images as low as 150ppi.

PPI is a more accurate term for digital images, dpi and lpi (lines per inch) are often freely interchanged by designers and printers when talking about offset printing.
 

compuwar

macrumors 601
Oct 5, 2006
4,717
2
Northern/Central VA
Alas the biggest I can print on my Inkjet is 8x10, what would you consider a "Non-discount" place? Is the built in printing in iPhoto (Kodak) good?

I've used Delano Color Imaging in Oklahoma with great results- especially for things that I didn't profile but wanted cropped and done right in a rush, WHCC does great work, and I've had good results recently with Adorama, who had a sale through yesterday on 11x14s that I wish I'd have gotten a hundred or so done (although I tend to sell 8x10s mostly.) Ace Photo in Sterling Virginia keeps trying to woo me, and I'll probably let them have a go but I'm not sure if they do over 8x10. I've never used the iPhoto built-in stuff so I can't comment on it. Dry Creek used to have profiles for several places local to me, but I don't think they keep many of them up to date anymore and I don't mind getting things done further away.
 

todd2000

macrumors 68000
Original poster
Nov 14, 2005
1,624
11
Danville, VA
Has anyone here used iPhotos built in printing for large prints? How did it turn out? I've gotten 4x6s before and they were great.
 

CDailey

macrumors regular
Nov 13, 2006
159
0
Florida
Since we're on the subject of printing, where do you guys get your digital images printed. The only places I can think of that pretty much anyone has access to is Wal Mart or CVS. I've got a few shots printed at Wal Mart and they were pretty good. The 4x6's from my 4mp Fuji S5100 looked great. I got an 8x10 printed (taken with the same camera) and it looks fine from a distance, but up close it looks kinda crappy. :-/ I havn't had anything from my dRebel printed yet, but I'm looking to get a few done soon. I don't plan on getting anything larger than 8x10 printed, so would it be fine to use a place like Wal Mart to get my stuff printed?

What do you guys recommend?
 

xrays

macrumors member
Jan 6, 2005
31
0
Toronto, ON
Has anyone here used iPhotos built in printing for large prints? How did it turn out? I've gotten 4x6s before and they were great.

I've printed about 30 16x20 prints from my Canon 20D sources (8MP, some JPG and some RAW originals), and all the images look fantastic at that size. You'd have to take a magnifying glass to the prints to see the original pixelization from the camera. However, the two prints I made at 20x30 did show signs of pixelization right away, so I've learned not to print that large with my current camera, regardless of how sharp the original photo.

If your camera is only 6MP, you might think of capping the size lower than 16x20, or maybe just trying one or two of your best (i.e. sharpest) images to see the results.

As for using iPhoto... That's the only way I've printed my larger prints. Apple uses Kodak, and they do a very good job. The turnaround isn't exactly speedy, but then I live in Canada so there's a bit of extra shipping time. I'd consider using Futureshop and/or Walmart simply for convenience, but not for anything larger than 5x7 prints.

I don't think you can go wrong printing 11x17 images through Apple's service. Go ahead and try a 16x20 print to see what you get back, and then you'll have a definitive answer for your own satisfaction.

Good luck!

x.
 

bousozoku

Moderator emeritus
Jun 25, 2002
16,120
2,388
Lard
Since we're on the subject of printing, where do you guys get your digital images printed. The only places I can think of that pretty much anyone has access to is Wal Mart or CVS. I've got a few shots printed at Wal Mart and they were pretty good. The 4x6's from my 4mp Fuji S5100 looked great. I got an 8x10 printed (taken with the same camera) and it looks fine from a distance, but up close it looks kinda crappy. :-/ I havn't had anything from my dRebel printed yet, but I'm looking to get a few done soon. I don't plan on getting anything larger than 8x10 printed, so would it be fine to use a place like Wal Mart to get my stuff printed?

What do you guys recommend?

I normally print everything at home, as my printer does up to 13x19, but I've used Wal-Mart and Sam's Club when I'm far away from home. The Kodak machines are acceptable but not great, even after I've corrected light and colour through Photoshop.

It seems as though the Kodak kiosk's printer has a slight lack of contrast. I can't say how the Fuji machine works because it couldn't find the photos on my card.
 
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