photoshop printing & resolution question

Nikon AF-S NIKKOR 24-70mm f/2.8G ED

10/05/2009 02:11:10 PM · #1

This is something I really should know--but I don't. So please help!

I'm going to my first nature photography club meeting tonight, and they want us to bring our favorite picture from the last two years. I opened two of my bluebird shots and looked at the image size (I want to print an 8x10).

It says the image size is:
1880 pixels by
1392 pixels

7.833" by
5.8"

240 pixels/inch

another bluebird picture says:
1558 pixels by
1426 pixels

21.639" by
16.806"

72 pixels/inch

What is the largest size I can print these pictures with optimal quality? Can I print the first one at 8x10 with a lower resolution and have it look excellent? Should I be changing the resolution of the 2nd one to something higher than 72 before I print?

Please help!

thanks! (the help feature doesn't explain any of this...)

Message edited by author 2009-10-05 14:13:27.

Citadel

Nikon D7500

10/05/2009 02:24:38 PM · #2

From my understanding optimal pixel density (if that's the correct term) for prints is 300 dpi. (72 is good for monitor though). So your first image at 300 dpi would be 6.26 inches by 4.64. If you change to 300 from 72 on the second image you'll probably lose quality. If possible you may want to reexport at higher resolution.

eta: sorry, the second one could be printed at 5.19 X 4.75 inches without scaling. When you scale an image you are adding/subtracting pixels so if all the pixels are already there then you're good. You may also want a second opinion on whatever my little brain is saying right now though

Message edited by author 2009-10-05 14:27:22.

Yo_Spiff

Olympus OM-D E-M5 Mark III

Olympus 12-100mm f/4.0 M.Zuiko ED IS PRO

10/05/2009 02:28:15 PM · #3

How big do you want to print it? DPI is a matter of pixel density, but is only an abstraction until you put the image on paper.

What is the resolution of the printing device? For arguments sake, lets say 300 DPI.

Divide the pixel count by the resolution you want to print at:

1880 pixels divided by 300dpi= 6.26 inches is the largest size that will get you optimum detail. Blow itup any larger and you will start getting jaggies.

Here is another thread on the topic from a few months back that may provide some more explanation. (And keep me from typing the explanation all over again!)

It's a confusing subject. I have even had difficulty explaining it to others within the printer trade.

ETA: You may be able to blow it up some without obvious jaggies. It is a perception thing. Can't take it too far, however.

Message edited by author 2009-10-05 14:31:22.

GeneralE

Canon PowerShot S3 IS

Canon 12x IS USM (S3 IS built-in Lens) -- 36-432mm (35mm EQ)

10/05/2009 02:46:53 PM · #4

In the Photoshop Image Size dialog, uncheck the Resample Image box, and you can then enter the dimensions to see what resolution you'll end up with, or enter the resolution and you'll see the largest size you can print.

As previously mentioned, you ideally want 300dpi at the final print size, but you should be able to get acceptable quality from most photo printers as low as 150dpi at the final print size; for example, DPC Prints will approve for public sale images as low as 150dpi.

Note that to end up with an 8x10 image you will probably need to either crop or border your image.

10/05/2009 02:46:59 PM · #5

'good resolution' depends on the medium and viewing distance. You can print a billboard at something like 40 dpi because nobody will be close enough to see the individual pixels, similarly, you wouldn't want to print a landscape for a gallery at 40 dpi because it will look like crap since people will be up close to view it.

printers recommend you print at 300 dpi, but honestly, I cannot see a different between 300 dpi and 240 dpi when I have upscaled photographs and I have printed at 200 dpi will fine results. If you go lower than 200 dpi, I would prepare for a slight degradation in the up-close quality but nothing that will make you cry.

I think people fear anything other than 300 dpi because they expect crap results but this isn't the case unless you have a totally crap printer/print lab.

Now, when I print, I print at 240 dpi.

When I display on the web it is at 72 dpi because anything above that is a waste and this also reduces file size. I have a photoshop action that converts image size, sets to 72 dpi and sharpens it for final display.

mpeters

Canon EOS-5D

Canon EF 50mm f/1.8 II

10/05/2009 02:49:38 PM · #6

Originally posted by Tez:

What he said. :) 240 dpi(or less in many cases) will give you very good results. I prefer to print at a lower resolution rather than resampling an image to 300dpi.

Canon 12x IS USM (S3 IS built-in Lens) -- 36-432mm (35mm EQ)

10/05/2009 02:51:33 PM · #7

argh! I'm so confused.

And a new, unedited photo of mine measures 1936 pixels. Does that really mean I can only print up to 6.5 inches??? I realize that the 40D doesn't have a huge number of pixels, but I would have thought that I could make quality prints larger than 5x7, but according to Spiff's post, it doesn't sound like it...

I'm sending it to Ritz to be printed.

Message edited by author 2009-10-05 14:53:12.

GeneralE

Canon PowerShot S3 IS

10/05/2009 02:51:57 PM · #8

This Tutorial may help: Resizing Pictures to Standard Print Sizes

Note: In printing, the "actual pixels" are not applied directly to the paper, but are instead used to calculate "printer spots" or "halftone dots" (used in commercial offset printing processes); each spot or dot can be made using the data from several pixels.

For example, when printing at 150 Lines (halftone dots)/inch on an offset press, such as a decent-quality magazine on glossy paper, each printed dot can be made using the data from four pixels in a 300dpi file.

Message edited by author 2009-10-05 14:59:02.

10/05/2009 02:55:06 PM · #9

Took a quick look at the tutorial -- but the question still boils down to this: With a Canon 40D, am I really limited to printing quality prints at 8x12 or smaller? Am I really using that poor of a camera?

10/05/2009 02:57:19 PM · #10

ok, first stupid mistake -- I think I'm viewing a small jpeg -- my raw files didn't get imported (have some weird glitches going on in elements). Let me check a different picture for pixel size before continuing...

10/05/2009 02:57:45 PM · #11

Originally posted by vawendy:

Multiply the number of inches you want to print by 300 and you'll find your image dimensions.

So a 5x7 would be 1500 x 2100. Likewise, an 8x12 would be 2400 x 3600 and so forth.

I used a 40d (before I got the 5d2) and I've printed at A3. It goes back to my previous point of how close people are going to get. 8x12 is great, 11x14 is great, 16x12 is great and the A3s are great but I wouldn't go bigger than that.

don't sweat it... again, like i said in my previous post... don't get caught up in the DPI and thinking you can 'only print at 300 dpi'. that rationale is bullshit.

Olympus OM-D E-M5 Mark III

10/05/2009 03:08:45 PM · #12

Ok, I'm beginning to get a handle on this. I've discovered that I can print my file as an 8x12 (it's only 150 resolution, but it sounds like it should be ok).

Do you actually go change the resolution in the image size box (with sampling unchecked) before you print? Or does the print command automatically print at the highest resolution possible given the size you input?

Yo_Spiff

Olympus 12-100mm f/4.0 M.Zuiko ED IS PRO

10/05/2009 03:17:45 PM · #13

When I print from PSP, I tell it to fill the page and it stretches or shrinks the image accordingly. The default DPI encoded with the file means nothing.

If anyone tells you "I need a 300DPI image", you also need to know the physical size it will be printed at, with those 2 pieces of info you will know if you have enough pixels.

10/05/2009 03:22:22 PM · #14

yes you change the resolution in the image size box.

Why was the final picture only 1936 pixels? Whatever happened to the other half of it?

8x12 at 150 dpi will be ok but won't be the best quality in the world. I would consider adding a plain border or something so you can squeeze more resolution into the image.

I think you're making this far more complicated than it needs to be. If you're really bothered, send 3 files through to be printed at different DPI and see what happens.

10/05/2009 03:35:31 PM · #15

Originally posted by Tez:

If my printer was working, I would do that. But ritz is charging $5 for an 8x10 -- so it gets expensive to experiment. :D

10/05/2009 03:38:20 PM · #16

try mpix.com

I think they're at $3 for an 8x10, or hell, make the files and take them to costco or walmart on one of those kodak machine things.

and I don't think $15 is a lot to ask to categorically KNOW what works and what doesn't.

10/05/2009 03:43:47 PM · #17

Originally posted by Tez:

I agree completely! This is just a last minute thing, so I needed to do it quickly, and money's a little tight at the moment. I usually send to Richmond Camera which is much less and much better quality than Ritz.

Curious, though, I've only used the "print it yourself" machines once. I thought the quality on those pix were not nearly as good as the big industrial machines. What have you discovered?