Aperture Image Resolution Problem

If you are indeed exporting correctly, it sounds like your email client is compressing the image. You might try putting the image in a zipped folder and emailing that, so the emailer does not see it as a jpeg.

Just to be clear, we are talking megapixels, not megabytes, right? Your description of a RAW 10-15 megapixel image being compressed to 1 megapixel sounds eerily like a 10-15MB RAW image being compressed to a 1MB jpg (which would be nornal and would not result in a smaller pixel count).

Try exporting an image to your desktop and check it out with "Get Info". It will give you the pixel dimensions. Did it work there? Try your export to email then drag the photo from the email to the desktop and check it out the same way. Is it correct? Is it the same?

How big are you printing?

What are the pixel dimensions of the files you are sending? (Get this information from Finder's "Get Info" dialog.)

Divide, for either height or width, the number of inches of the print by the number of pixels of the image to determine the PPI. (Ignore the DPI setting in Aperture's export dialog -- it's just a number, and is misleadingly labeled.)

Also confirm that you export presets are in fact set as you think they are (the names are purely descriptive -- it's possible to have an export preset "Whopping Big File" set to "2 x 2 pixels".)

Agree.

OP:

A quick review, just so we are on the same page.

Digital image files have two "sizes".

The actual image size is measured in pixels. The digital image comprises a grid of colored dots. Each dot is a pixel, which is short for picture ellement. The dimensions of the image are given as so many pixels in one direction (usually height) by so many pixels in another direction (usually width), e.g.: 600 x 800 pixels, or 4,000 x 6,000 pixels. The overall "size" of the image is calculated by multiplying the height by the width. In the examples given, the first image is (600 x 800 = ) 480,000 pixels. The second image is (4,000 x 6,000 = ) 24,000,000 pixels.

That's a lot of pixels. The size is often given in megapixels, where 1,000,000 pixels = 1 megapixel (abbreviated MP). So the first image is approximately half a megapixel, and the second one is 24 MP.

Pixels themselves have no other unit of measurement. There is no way from the pixel count to know how many inches (or centimeters) an image will be when printed or shown on a screen. In order to determine that, you must have the pixels-per-inch (PPI) of the printer or screen (or projector, or any other display device). A 600 x 800 px. image, at 100 PPI, will be 6 x 8 inches.

Pixels are device independent. PPI tells some programs and devices how big to display (or print) an image.

The other image file size measures how much data is in the file. Data is measured in bytes. One thousand bytes is a megabyte, abbreviated "MB".

Generally, the larger the image size, the larger the file size. But this is not necessarily so, and shouldn't be used as anything but a very general guide.

Your question is about resolution, which is a question of density: how many pixels there are in a given area. This is commonly measured in PPI. Resolution and file size are independent.

Message was edited by: Kirby Krieger

What are the dimensions the image will be when printed? The page size sets an outer limit -- the image will be printed smaller than 11 x 13 inches -- but tells us nothing else about the dimensions that it will have when printed.

When Blurb says "DPI" they mean PPI. 😉 .

Generally, 100 PPI is low for a high-quality print. 200 is good. 300 is generally considered the minimum needed _to assure_ top quality.

At 96 ppi, a 10 x 10 inch print will require an image that is 960 x 960 pixels. 960 x 960 pixels is 921,600 pixels, or close to 1 MP.

Your c. 4,000 x 2,600 px image should be printable up to at least 20 x 13 inches and look very good (20 x 13 inches at 200 PPI is 4,000 x 2,600 pixels).

Export one to an ordinary folder, and in that folder check its size with Preview or another photo app.

If you are using Apple Mail, check the status of the image size button at the bottom of the compose window.

Ernie

Got it. Confirm the actual pixel dimensions of the exported file when you can. 11 x 13 inches at 200 PPI is 2,200 x 2,600 pixels. Anything that big or bigger should print fine.

Note that the aspect ration of the page (11/13) is 0.85, and the aspect ratio of your Image is 0.66. Either your image will have to be cropped, or it will not fill the entire page.

"I then uploaded the same image, this time directly from Aperture. But this time I received a low image resolution warning from the blurb software."

How did you upload directly from Aperture?

(Sent from my magic glass.)

Ahh. It would appear you are using the Aperture preview image. If you use the media browser or drag&drop from Aperture to somewhere else, the preview image is what you get. If your preview images are set to "unlimited", you'll get full-size previews and then you can drag&drop or use the media broswer and get full-size images. You'll have to set this preference and regenerate previews if you want to use this workflow versus exporting via Export.

Aperture/Preferences/Previews, set Photo Preview to Unlimited. Set the quality to what you want.

I believe to regenerate previews you click on Photos (under Library, in the sidebar) then, from the menu bar, Photos/Update Previews for Library

Larger previews take up more space. Make sure you have the drive space for them. They'll each be a full-size jpg.