Low resolution warning?

Question

I have the Nikon D80 and have it set to fine and large file format and can't seem to enlarge bigger than an 8 x 12. Is Aperture possibly compressing the files somehow, or changing the mega pixels when I export the photo?

Answer 1

What are the pixel dimensions of the Image?  What do you mean by " ... can't seem to enlarge bigger than ..."?  Are you printing? exporting?  Using what settings?
Fwiw, the first bullet point from the guidelines on this page in the User Manual is likely apposite:
Printing Tips
Here are a few suggestions to help you with the printing process:
Use the highest-resolution image possible: It’s preferable to work with images imported directly from your digital camera. However, even images imported directly from your camera or card reader can be low-resolution, low-quality images. This is why it’s important to shoot with the highest-resolution settings available on your camera. Compression settings applied during image capture may be apparent when you print. Consider shooting RAW files if the setting is available, and shoot at the highest bit depth possible.If you’ve imported an image that was reduced or compressed in another application, Aperture cannot increase the resolution of the file. In other words, Aperture cannot replace image information that was previously removed during the compression process. If possible, locate the original full-resolution image file, use the Lift and Stamp tools to apply the adjustments you’ve made to the low-resolution file, and print the higher-resolution image file.
Use a printer that supports 16-bit printing: If the image you’re printing is a high-resolution 16-bit file, using a printer that supports 16-bit printing results in smoother gradations.
Color calibrate your Aperture system: It’s important to calibrate your display and printer so that your printed images look as much as possible like the images you see on the computer screen. For more information about color calibrating your Aperture system, see Calibrating Your Aperture System.