How many pixels is 8.5 x 11 in.?

Question: How many pixels is 8!.5 x 11 in!.!?

I'm trying to enlarge an image!.Www@QuestionHome@Com

Best Answer - Chosen by Asker:

Why do people quote dpi when replying to any question about printing!?

Dpi (dots per Inch) is the resolution of the printer and bears no relationship to size, I routinely alter my file size to print 6ft X 4ft prints, when I send them to my printer it prints them at the size I set at a resolution of, you guessed it 300 dpi!. Dpi is the resolution of the printer NOT the resolution of the print which is in ppi (pixels per Inch)!.

Only two thing determine print size, how many pixels you started with and file size!.

For instance a 6Mp camera will print 'natively' (natively means no resizing up or down) a print of slightly larger than 10" X 8" a 10Mp sensor will print natively at about 16" X 10!.5")!.

If you want to print larger (or smaller for that matter) than the native format then you have to 'interpolate' to add pixels to cover the paper!. Interpolation is necessary, but reduces quality because (in the case of printing larger) it 'invents' pixels to cover the extra paper area by looking at the data and inserting pixels the values of which are determined by the valid data around them, so should be kept to a minimum!.

In Photoshop this is done in the Image Size dialogue box, but all image manipulation programmes have something similar!. Make sure the 'Resample Image' box is checked enter the size required (8!.5" X 11") and just play around with the resolution (ppi) till you get a file size that equals 1M of file size to every inch on the longest side of the print, so for your 8!.5" X 11" you are looking for a resolution that gives you an 11Mp file size!.

This is the smallest value for a quality print and ensures the minimum of 'interpolation'!.

You need to start off with enough pixels, if it's a downloaded image or from a low res source such as a mobile phone camera there wont be enough information in the file to enable a print of any quality to be achieved, there would need to be too much interpolation!. For the size you want you need to be starting with at least 2Mp (2000px X 1000px) from the camera sensor!. Most mobile phones output an image that is already interpolated from a tiny sensor and are useless for print!.

When you send this file to the printer it will print at the size you set at whatever resolution you set the printer at!.

ChrisWww@QuestionHome@Com

Just do the math: 8!.5 x 11 x (DPI) x (DPI)
At 300 DPI, it's about 8!.4 million pixels!.

EDIT ***

"Why do people quote dpi when replying to any question about printing!?"

Because the printer will resample the image if you send it something that doesn't match its DPI, and most printers use 300 DPI or a multiple of it!.

As any Flickr or Eyefetch user knows, not all resampling algorithms are created equal!. It may be better to resample in Photoshop!. It may be better yet to be able to capture an image that needs no resampling at all!.

This point is especially sensitive for images whose character makes them sensitive to moire effects!.Www@QuestionHome@Com

You'll most likely be wanting 300dpi (dots/pixels per inch)!. Lower resolution will appear more grainy!. The maximum resolution of the print head will influence the highest DPI used successfully!.

Using 300dpi as a guide you'll have 2,550 x 3,300 pixels!.
The reference below is a good forum thread discussing resizing photos with DPI in mind!. Note that digital cameras are commonly capturing at 72dpi!.Www@QuestionHome@Com

8!.5" x 11" is equal to 1700 x 2200 pixels!.Www@QuestionHome@Com

Just set your DPI to 300 and you should be fine!.Www@QuestionHome@Com

Don't know!.Www@QuestionHome@Com