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03/15/2006 10:34:12 PM · #1 |
A couple of my photos/digital art have been accepted for print at my college's zine...and they need the images in 300DPI for printing. Now when I go into image size in photoshop and I see the largest dimensions my old camera could muster, and 72DPI...how am I gonna get it to 300DPI?
Is that a matter of slowly upsizing?
There is going to be a loss somewhere, right? Which is better: printing at 72DPI or up-sizing to 300DPI?
Also, if I've got this backwards, can someone give me a crash course?
Many apologies for not hunting this info down in a forum search, but it's a bit urgent......
Thanks so much!
Katy
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03/15/2006 10:43:53 PM · #2 |
Originally posted by kdkaboom:
A couple of my photos/digital art have been accepted for print at my college's zine...and they need the images in 300DPI for printing. Now when I go into image size in photoshop and I see the largest dimensions my old camera could muster, and 72DPI...how am I gonna get it to 300DPI?
Is that a matter of slowly upsizing?
There is going to be a loss somewhere, right? Which is better: printing at 72DPI or up-sizing to 300DPI?
Also, if I've got this backwards, can someone give me a crash course?
Many apologies for not hunting this info down in a forum search, but it's a bit urgent......
Thanks so much!
Katy |
How large will they be printing the photo?
~Terry
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03/15/2006 10:46:56 PM · #3 |
Photoshop is your friend here.
DPI is a measurement of how many pixels per inch measured across the diagonal of a square.
Printers these days can feature some very high DPI measurements, but 300DPI is standard high print quality.
To get your pic to 300DPI, there are two methods. One is to use software specifically designed for this (sorry can't help with names here, others will undoubtedly). The other is to simply use photoshop. I believe you can upsizing in 5-10% increments. Most use Bicubic Resampling. In Image size, you change the DPI to 300 and it will show you the print size in inches. Then slowly increase up to the size of the print you wish to make. The printer will then take what information is available in the shot and print whatever it's configured for (usually well above 300DPI) at the dimensions you request.
The final result will be pretty close to 300DPI if the printer is any good.
I hope others fill in the gaps I've left. I'm not really an expert, but I figured I'd post as there were no others and she said it was urgent. |
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03/15/2006 10:48:00 PM · #4 |
| The important number is not the DPI because you can adjust that to fit your printing needs. The important questions is what is the total pixel dimension of your shots? That tells you how many pixels total you have to work with. |
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03/15/2006 10:58:31 PM · #5 |
Okay! Thanks guys!
Print size: ahaha! NOT BIG! I was told by the not-so-with-it folks to give them the image at 300DPI to fill a 8.5 x 11 page :)
I have a feeling this isn't an issue, and even if it's 72DPI it'll print fine!
BTW, the images in question are 1536x2048...72dpi....
I've read the tutorial on up-sizing, so I get that. But I do see that if I alter the pixel dimensions, the DPI doesn't change. If I alter the DPI, the pixel dimensions DO change.
Again, I have a feeling that the guy who gave me this info isn't really sure either.....I bet if I gave him just the full size image, 72DPI, it'd be FINE!
I really appreciate your help here. It's confusing stuff!
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03/15/2006 11:27:40 PM · #6 |
If they are printing in a magazine by offset printing methods, 72dpi at the final print size will definitely not be fine. To print magazine quality by offset you need a bare minimum of 200 dpi, and 300 is more-or-less standard. If they say they want it at 8x11 @ 300, then 8x11 @ 72 will not do the job at all ...
Remember that dpi (really, ppi) is a measurement of how many pixels there are per inch of final output. 11 inches at 300 ppi is 3300 pixels -- it doesn't really matter whether you set it at 300 or 72 ppi, you still need 3300 pixels.
That 3300 pixel image will print 11 inches at 300 ppi, 33 inches at 100 ppi, etc.
The reason you need more dots is because of the way photos are print by offset. There are no "shades" of ink color -- a press is a binary device (ink/no ink) -- and colors are imitated by using different-sized dots of ink (the "halftone screen"). Typically, there are about 150-200 of these dots per inch. Having a file with 300 ppi, lets each of those halftone dots have its value determined by taking the average of 4 pixels, and historically provided the most accurate reproduction.
One can often get acceptable results with a 1.5:1 sampling ratio (225 ppi), and you can get barely adequate results at 1:1 (150 ppi), though at our shop we'd only use that if desperate. At 72 ppi, you'd be at less than half that sampling ratio, and you will get unacceptable pixelization, banding and/or jaggies. |
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03/15/2006 11:34:56 PM · #7 |
Try this:
In Photoshop, go to Image--->Image Size. UNCHECK the 'Resample Image' box. Now, change the resolution to what you need. Hit ok.
Now go to Image---->Image Size again. Now to your resizing as per the tutorial.
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03/15/2006 11:36:15 PM · #8 |
Ohhhhhhhhhh.
Good stuff, General, many salutes and salutations!
I will then go ahead and upsize delicately :)
I imagine the size of the image will be huge and have to be delivered on CD. Dangit.
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03/15/2006 11:51:43 PM · #9 |
8.5" x 11" @ 300 ppi in 8-bit RGB mode = 24.1MB in uncompressed TIFF format; grayscale will be about 8MB. Your best quality will be preserved if you save it as a TIFF and make a ZIP (PC) or Stuffit (Mac) archive file, which should get it to between 10-50% of the original size.
You should be able to upload it to them via FTP, in which case there's no size restriction other than upload time.
If you have Photoshop CS, then the recommended upsizing method is in a single step using the Bicubic Smoother option, rather than the "step" or "stair" interpolation (upsizing in 5-10% increments) suggested for use with older versions.
BTW: Congratulations! Be sure to post a photo of the magazine page when it's been printed.
Message edited by author 2006-03-15 23:52:47. |
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03/16/2006 02:01:10 AM · #10 |
Originally posted by GeneralE:
If you have Photoshop CS, then the recommended upsizing method is in a single step using the Bicubic Smoother option, rather than the "step" or "stair" interpolation (upsizing in 5-10% increments) suggested for use with older versions. |
This is correct. I validated it by upscaling using both step interpolation (Fred Miranda's SI Program) and CS2's bicubic smoother in one step and they were literally indistinguishable when putput was examined at 100-200%. The big difference is that bicubic smoother is much, much, much faster. Goodbye to Fred Miranda's Step Interpolator for me.
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10/15/2006 07:44:56 PM · #11 |
| Well, what about a 16x20 photo? The original photo has 3072x1789 resolution. I resized it to 16" x 20" and now the resolutions are 9000X7200. What should the dpi be? |
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10/16/2006 10:43:11 AM · #12 |
Originally posted by kdkaboom:
Okay! Thanks guys!
Print size: ahaha! NOT BIG! I was told by the not-so-with-it folks to give them the image at 300DPI to fill a 8.5 x 11 page :)
I have a feeling this isn't an issue, and even if it's 72DPI it'll print fine!
BTW, the images in question are 1536x2048...72dpi....
I've read the tutorial on up-sizing, so I get that. But I do see that if I alter the pixel dimensions, the DPI doesn't change. If I alter the DPI, the pixel dimensions DO change.
Again, I have a feeling that the guy who gave me this info isn't really sure either.....I bet if I gave him just the full size image, 72DPI, it'd be FINE!
I really appreciate your help here. It's confusing stuff! |
IMO, its easier to think about the total number of pixels.
8.5 x 11 at 300 dpi is 2550 x 3300, so you have to upsample if the picture will be printed full page.
If the folks are really not-so-with-it, you should check to see if they will print your image full page, becasue upsampling then downsampling will degrade the quality.
1536x2048 at 300 dpi gives a 5.12 x 6.827 picture, which is the largest you can supply without upsizing.
Does anyone know if there's an advantage to using an evan multiple (like 200%) to upsize (or downsize), rather than a fractional multiple? I couldn't tell from an on-screen test. |
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