# Image Dimensions vs. Print Size and Cropping



## Guido44 (May 7, 2009)

Hi all,

Can anyone point me to a good link (or advice) on image dimensions vs. actual print sizes. What I mean is, how the actual each photo will be cropped with regard to each individual print size?

I did some test prints yesterday, and I was a little disappointed that depending on the print dimensions, my shots had about 5 or 10% of the top and bottom cut off, or the edges. 

Is there a preferred image size? Do you limit the prints sizes available to clients to avoid screwing up (cropping) your work?

My D300 takes originals at 2848 x 4288. 

Thanks,

dan


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## Big Mike (May 7, 2009)

It's just a matter of simple ratios.  

The common print sizes do not have the same aspect ratios, so there will need to be cropping for those different sizes.  Most DSLR cameras shoot with a native ratio of 2:3, good for 4x6 or 8x12 prints...but there will be cropping for 5x7 or 8x10 prints.

So are you asking about size files to give the clients?

I think the common practice is to give them 2:3 files, but leaving enough 'space' in the photos for 8x10 cropping.


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## KmH (May 7, 2009)

You might google 'aspect ratio". I think Wikipedia.org has a fairly good writeup on aspect ratio too.

The most common image aspect ratios are 2:3, 4:5 and 5:7. The ratio is the short side to the long side of the image. In the 2:3 aspect ratio the long side is 3 units, the short side is 2 units. Expressed another way, the long side is always 1.5 time the short side. 4:5 the long side is 1.25 times the short side and 5:7 the long side is 1.4 times the short side.



2:3

4x6
6x9
8x12
10x15
16x24
20x30
24x36
4:5

8x10
16x20
5:7

Wallets
5x7
10x14
20x28
There are some other aspect ratios out there like 1:1 which is square.

The issue of image size to actual print size refers to output resolution which is expressed as pixels per inch (ppi). Output resolution is only valid when it is used relative to the linear dimensions of an image.

Your cameras output size, 2848 x 4288 is not a linear dimension (like inches) it is a spatial dimension (pixels). There is no standard pixel size.


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## ANDS! (May 7, 2009)

Doing too much work.  If you are using Photoshop, simply set the dimensions of your crop tool to your printers output and then crop as needed (making sure to keep the desired DPI).  No need to remember rations of sides and all that wonky nonsense.


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## Dwig (May 7, 2009)

KmH said:


> ... Your cameras output size, 2848 x 4288 is not a linear dimension (like inches) it is a spatial dimension (pixels). There is no standard pixel size.



Quite true, but ...

... all common digital images use square pixels and all common sensors use square photosites. Thus, the pixel "dimensions"  of your image can be used to determine the aspect ratio of your image. The 2848x4288 mentioned has a 2:3 aspect ratio.

When dealing with borderless prints you also have to keep in mind that it is MANDITORY for the printer to spill some image past the edge of the print to allow for minor tracking errors as the paper moves through the printer. As a result, there will be some cropping on all edges even when you match the image and print aspect ratios. My HP B9180 "crops" about 2-4% of the image by linear measure.


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