Florian,

Fantastic! One final bit of advice for you… no need to go as high as 12 on the quality. I spoke with a very experienced printer who assured me that Q12 was just marketing hype and really you can’t see the difference from Q10—it’s virtually imperceptible. If you want to compare and have Photoshop, export the same image at the same size using both 10 and 12, stack them in Photoshop, and apply a Difference blend mode. See if you can see anything… that’s the difference between the two. If you want to push that to an extreme, then flatten those two layers and run auto-levels a couple of times. That’ll force any differences to super bright, and you can see where the differences were—but keeping in mind that you probably couldn’t see them to begin with.

Q10 is a significantly smaller file than Q12, in my experience.

cheers,
-Joseph

Florian,

Thanks for the extra info—that helps.

MPIX is limiting the size you can print based off the actual resolution—any quality print service will do that, to keep you from ordering a print that won’t turn out well. If they are requiring a 20x30 inch photo to be 2000x3000 pixels, that’s 100dpi (dots per inch, also displayed as PPI, or “pixels per inch”), which is actually quite low. Best quality prints are typically at 133dpi or higher, up to 300dpi.

You said your original files are 1584x2376, which is only 3.7 Megapixels. That’s a VERY low resolution file to be printing at 20x30 inches. As a point of reference, the iPhone 3GS shoots at 3.1 Megapixels, or 1536x2048. If you printed your image at 20x30, it will print at 79dpi, which again is very very low. I can promise you that you will not he happy with the quality of the print you get.

Technically it is possible to increase resolution, but you’re not adding data of course—you’re just making up pixels that didn’t originally exist, and the quality will not be great.

My recommendation is to print at a smaller size. MPIX is saying 12x18 is the max, which is 132dpi, and will give you a good quality print. I’d follow their advice and only print at that size.

If you’re determined to get a 20x30 inch print, regardless of the quality, you can increase resolution in Aperture by building an Export Preset that will output the exact size you desire. Go to the menu Aperture > Presets > Image Export…, create a new preset with the + button at the bottom right, and set it up to your specifications. You can do it by pixels, or even inches or cm and resolution; so 20x30 and 100dpi.

You also asked about other printing services. Did you know that there’s a print service built in to Aperture? Just select your image(s) and choose File > Order Prints…. This will connect you to Apple’s print services company and allow you to order prints directly from within Aperture. This service is available in most countries, I believe. It will also, however, limit the size of what you can order, based off of resolution.

cheers,
-Joseph @ApertureExpert

Thanks for the help Thomas!

Florian, Thomas nailed it—you’ve solved the problem. And there’s no need to send MPIX an exact size image. Just send them the “JPEG - Original Size” file and let them print from that.

And no, Aperture doesn’t print gallery wraps or anything like that. So if that’s what you’re after, then MPIX is great.

One more thing I’ll advise—be sure to zoom into your photo at 100% (tap the Z key in Aperture) and pan around the entire image looking for anything you may need to retouch, such as dust, sensor spots, stuck sensor pixels, etc. Aperture’s retouch tool (tap the X key to bring it up) is fantastic and works really well for those kinds of problems. (Check Aperture’s manual on how to use it if you’re new to it.) When printing a high resolution image at a small 4x6 print, you wouldn’t notice these problems—but when you print big at 20x30, you’re going to see every “mistake” on there. If you haven’t already done this, you’ll be surprised how many “little things” you might find on your photo.

Good luck and let us know how your print turns out!
-Joseph @ApertureExpert