# Question about resolution/image size



## StevenisWhere

About 80% of the time, I will only be looking at my pictures/posting my pictures on a computer screen, but my question is for that 20% of the time that I will be printing my photos.

I just got a Nikon D5000, and have been taking photos in RAW, and editing them using Aperture 3 and Photoshop.

My question is about image size. I already read all the tutorials about ppi and resolution and all that jazz, but I'm a little confused.

When I go to resize my image, I set the ppi to 300 (with resampling turned off), and it says then that the document size is ~14x9.5

14x9.5 is by no means small, but I was expecting to be able to print larger sized photos with a D5000.

For those of you that print your photos often, do you always use 300ppi, or do you go smaller?  What's the lowest ppi that should be used for good quality, large prints?

Thanks for the help.

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## Phranquey

StevenisWhere said:


> For those of you that print your photos often, do you always use 300ppi, or do you go smaller? What's the lowest ppi that should be used for good quality, large prints?


 
A lot also depends on the viewing distance.  I always use 300dpi when I can, but you can go less for larger prints and still get very satisfactory results, as long as you aren't putting your nose right up to the print.  You can easily go to 200dpi for a nice wall print that will be viewed from the couch, but some pixelation will be visible if you get real close.


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## KmH

StevenisWhere said:


> For those of you that print your photos often, do you always use 300ppi, or do you go smaller? What's the lowest ppi that should be used for good quality, large prints?


The key is: ppi means Pixels-Per-Inch (and is vastly different from dpi)..s, without cropping the native resolution of your D500 is 4288 pixels x 2848 pixels.

At 300 ppi, _regardless resampling being on or not_, the image would print at 14.3 x 9.5 inches. (4288/300=14.29  ...2848/300=9.49)

The same image at 200 ppi will be larger because there are fewer pixels in an inch, 1/3 fewer per inch and the sides of the image will be 1/3 longer or 21.4 x 14.2 inches. (4288/200=21.44  ......2848/200=14.24)

The size of a print determines how far away from it people tend to stand to view it.

People will stand farther from a 21x14 print than from a 14x9.5 print generally. Thus, they would probably percieve the quality as being equal.

At one point in the past, for comparison purposes, it was decided a digital image printed at 300 ppi was equivelent to a print made from a film negative and that number persists to this day. 

However, it is far from being an absolute.

The reality is the lowest ppi that should be used for good quality, large prints _is entirely dependent on the image being printed._

I have had large (20x30 and bigger) prints made from images that had to be carefully up sized to pixel dimension so the print could be made at 400 ppi. Anything less was not a good print.

I have also had large (20x30 and bigger) prints made from images that were cropped from their native resolution and used as is, after editing, at 100 ppi with no quality issues.


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## Dwig

StevenisWhere said:


> ...What's the lowest ppi that should be used for good quality, large prints?...



It depends on a number of factors. Primarily the print size and viewing distance are the main considerations. The printing medium and printer come next.

For prints that will be viewed closely, regardless of size, the minimum printing resolution is around 300ppi. I generally upsample when necessary to get an image that is 300ppi at the printer. You don't gain real detail with the upsampling, but it does avoid aliasing and allows you to do the final sharpening at the printer's output resolution so that any sharpening artifacts aren't upsampled.

Also, I frequently make large prints for use on signs. These can be very large (10x20 feet or more). I generally prefer to keep to the 300ppi rule for smaller images (under 2-3ft long dimension) but often let the PPI drop to the 150ppi range when making very large prints. With extremely large images that will be viewed at long distances, I still hold to a 100ppi minimum when possible.

When the viewing distance is large lower resolutions are fine. There's a picture of a foot on a sign here in Key West that's about 4 ft square (a sign for a foot doctor) that I took with an 8mp camera and cropped to a square. It was printed at 150ppi after some upsampling (roughly a 2200x2200 pixel area of the original 2448x3264 pixel image as used) and looks perfectly sharp and smooth. From the point of view of someone driving by, its never any larger than a 4x4 inch print would appear when held at reading distance. Even when you walk by on the sidewalk its still far enough away that its never any larger that what a 16x16 to 24x24 inch image would appear at arms length.


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## StevenisWhere

Thanks for your explanations!  Your responses really help me understand it better

Now time to go get some prints!


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