ifurnish Loc: Katy, TX

Does anyone know of a good article explaining this? I have googled and cannot seem to find one that I understand. I recently ordered a large print but could only get it done in a 16x24 and not a 20x24. Any help appreciated.

Linda From Maine Loc: Yakima, Washington

Here is one:
http://digital-photography-school.com/aspect-ratio-what-it-is-and-why-it-matters/

Example, for 3:2 aspect ratio, multiply each side of the colon by the same number to keep the "aspect" the same and to not crop anything from your original image:

3x2 is same as 6x4, 12x8, 18x12, 24x16, 30x20

We reverse the numbers in printing to read 4x6, 8x12, 16x24 even though we say 3:2 aspect ratio...just to keep life interesting, I guess

From the above examples you'll see that if using a 3:2 camera, and you want to print a 20x24, you lose six inches on the long side. You can usually select how you want the image cropped even with online printing services (e.g. Costco), where you upload the file, or crop it yourself in editing prior to upload.

Finally, a simple way to envision the concept of aspect ratio is this: if you have a rectangular image and want to print as square aspect (1:1), something's gotta give

PhotomanTom

Most DSLR camera's provide an aspect ratio of 2-3. That gives full frame enlargements of e.g. 4-6, 8-12, 16-24 etc., any other size reproductions (prints) can be achieved by cropping the original to your desired size e.g. 8-10, 20-24. By cropping you of course loose picture area on either the horizontal or vertical edges. Some photo print businesses will only print to full frame or original aspect ratio because they don't know what area you, the customer, would be willing to lose in a cropped print.

The answer, of course, is to crop your own images in your processing software to your desired aspect ratio and have the result printed.

SonyA580 Loc: FL in the winter & MN in the summer

Kinda depends on what you sent them to print from. If you originally have a 4x6 inch photo, unless you want it severely cropped (trimmed in size), you are limited to maintaining that 2:3 ratio. So, enlargements to 8x12 or 16x24 are some of your options. If you start with a 4x5 inch photo you can get enlargements of 8x10, 16x20, etc. Some photo labs will print at different ratios than the original (Ex. 4x5 printed as 16x24) but you have to tell them what part of the original you want to eliminate. The other alternative is to have the final result distorted to fit into the odd format. Sometimes this works but mostly it looks ...., distorted.

dpullum Loc: Tampa Florida

I have written a Presidential Decree that we, the USA, only support particular aspect ratios. The automated machines will no longer be allowed to arbitrarily whack off part of your photo with auto crop!! It is time for the United Nations to step in and standardize the world of paper!!! Why when 8x10 [8.5x11] is a popular [home printing and frame/matt] size drug stores of course off 8x10, but for small show/tell prints the size is 4x6, not 4x5. To prevent auto crop, I resized the canvas by batch using Faststone Resize. Indeed paper world wide is a hodgepodge mess of sizes.
http://resources.printhandbook.com/pages/paper-size-chart.php
Rant done!

There are some photos that one can change the aspect ratio to fit the print and no one will ever notice [Except for Linda]. With landscapes no one will know if the tree is a little shorter or the steam a little wider. one ocean sun set [red in clouds] was taken in portrait out of necessity [building i was in blocked landscape view] I widened it about 25% and so the buildings were shorter, as were the trees, but if you were not familiar with Mar del Plata downtown beach area, you would never know that that photo was a real cheat of aspect ratio. You are in charge of the software and photo not the other way around.

Moral of the story, if you have a standard size for exhibiting, make life easy and crop to fit that size or change the aspect ration by un-checking the keep aspect ratio box in the "image resize" menu.

SharpShooter Loc: NorCal

Possibly what you are misunderstanding is dpi and poi?
As a print gets bigger, a printer may decide you don't have enough dpi.
Make sure you understand that as well. Good luck!
SS

Linda From Maine Loc: Yakima, Washington

Title of the topic is "aspect ratio." You're used to more ambiguous titles and having to puzzle out their meaning

Linary Loc: UK

I wondered what "poi" was, so I looked it up - "Poor Obfuscation Implementation"

Not sure of its connection with Aspect Ratio.

BebuLamar

I can't think of a camera that can take pictures that could fit into a 20x24 without cropping. If the printer said that they won't make 20x24 even with cropping then may be their equipment simply don't print that size (or can but with a lot of waste).

Linary Loc: UK

Here is a list of photographic paper sizes, inches and millimetres together with aspect ratios. http://www.zabbage.com/paper-sizes.htm

Linda From Maine Loc: Yakima, Washington

Nice resource!

I also thought of a way to define aspect ratio at its simplest: shapes

So while a 16x24 and a 20x24 are both rectangles, they are not the same shape rectangle. Think of old tv's: they were 4:3 while newest are often 16:9. Both are rectangles, but you can't fit a 16:9 picture into a 4:3 tv

Gene51 Loc: Yonkers, NY, now in LSD (LowerSlowerDelaware)

First you need to determine the ppi required for your print size.

This will help:

http://www.photokaboom.com/photography/learn/printing/resolution/1_which_resolution_print_size_viewing_distance.htm

Once you have that you can do the math to figure out what you need, in pixels on each side, to print to the size you want.

Using the chart a 16x20 requires a minimum of 89 ppi. If you multiply 89 times the dimensions of the final print you end up with 1424x1780. If you want to use a higher resolution for better viewing at closer distances you can use a higher ppi number. For argument's sake you decided you need 180 ppi which is actually a lot - you end up needing 2880x3600.

So, your image must conform to this proportion, 4x5 or a multiple thereof. If your image is a different proportion - like 2x3 (same as 4x6) then you will either print the full width and have extra space on the top and bottom, or print full height, and need to crop the edges, to conform to the 2x3 proportion.

A 20x24 is the same proportion as a 4x5 and a 16x24 is the same as a 2x3.

Linary Loc: UK

Do you not mean "A 20x24 is the same proportion as a 5x6"

BebuLamar

That what I meant that I know of no camera can produce image that fit 20x24 without cropping. So if you have to crop to fit then an image from a 3:2 camera can be cropped to fit.

via the lens Loc: Northern California, near Yosemite NP

Hi ifurnish,

First, the size you wanted is an odd size for printing for the most part. So, your primary problem is that you requested a size that the print shop you chose just does not print in. But they do, apparently, print on 16 x 24 paper and that is why they offered that size for your print. Bay Photo will give you a print that is 20 x 24 so you might check them out, bayphoto.com. They provide quality prints at a decent price and are very quick to do the work and send it to you. It's all done online. I have attached their list below showing the 20 x 24 print.

As for sizes in general. In the "old days, i.e., film" prints had standard sizes of 5 x 7, 8 x 10, 16 x 20, and many print shops today still operate from that perspective, although it is changing (and I don't think film was even sized exactly to those sizes). Since dSLR cameras shoot in a different format (ratio), 3:2 (an image that is longer than it is tall), than the offered print sizes, any photo you take will need to be cropped in order for it to fit into that "old style" sizing. The cropping will come from either one side or a bit off both sides, which works well in many cases.

If you do not crop the image, you can have it printed at its original digital format sizing of 4 x 6, 6 x 9, 8 x 12, 10 x 15 (which can be fit into a 16 x 20 frame so many people use this size), 12 x 18 (for a larger frame), 14 x 21, 16 x 24, 18 x 27, and the list goes on (hopefully I've got my math right). What these numbers have in common is that you add to the "3" and to the "2" the same number to figure out the sizes. So, if you add 3 + 3 you get 6; and then 2 + 2 you get 4 -- for a 4 x 6 print and so on, each time adding either 2 or 3 to the number, depending on the side, to figure out all of the print sizes. I talk about this on a web site I have for Lightroom/Photography, viathelens.net.

Hope this helps.