The importance of the aspect ratio in photography, do you know why they crop your photos when printing them?

Today I come with one of those topics that we take for granted and, however, when push comes to shove, they bring a lot of headaches. It’s about the aspect ratio in photography and image printing. Simplifying, the photographs when taking them have a size, however, the prints have other measurements. That is why I want to make a stop to clarify it and make sure that you have this topic clear and, if not, that you discover its importance and how it can help you develop your photos.

In addition, the aspect ratio in your photos can not only cause you to be upset when you receive your printed photo and see that it is cropped or (hopefully) that it has white borders that you did not expect, but it also influences the final result. and how photography is perceived at a compositional level.

This is what we are going to talk about today, you are interested, right?

  1. What is aspect ratio in photography?
  2. How does aspect ratio affect photo printing?
  3. Aspect ratio and composition
  4. How to determine the aspect ratio of my photos?

What is aspect ratio in photography?

Aspect, proportion, aspect ratio, etc., is the relationship between the width and height of the photograph. When this is expressed as two numbers separated by a colon (3:2), the first usually refers to the horizontal side of the image and the second to the vertical. Another way to express it is with a decimal number that results from the division of both digits, for example, 3:2 would be 1.5. Although in this case, the horizontal or vertical orientation of the image is ignored.

It is also often called more colloquially photographic format.

To clarify this about numbers a little more, 4:3, for example, means that on one side it would have 4 parts and on the other 3, regardless of size. For example, here we see a ratio of 3:2 and another of 3:4.

Here the same aspect ratios with an image:

If we divide 4 by 3 it gives us 1.33 (that would be the decimal proportion we were talking about before). Multiplying the shortest side (3) by 1.33 gives us the size the longest side needs to be to maintain the 4:3 ratio. An example, a photograph that measures 10cm on its shortest side, to maintain the 4:3 ratio, it will have to be 10×1.33, which would give 13cm. And that is the measure that the print must have (10×13) so that it is not cut off by one of its edges. I do not want to go into complications of formulas and calculations now, it is just to situate you. The idea that I want to convey to you is simpler and has to do with the following sections.

The aspect ratio is determined by the size of the sensor, although some cameras allow you to change it at the time of shooting. Also, it is always possible to change the aspect ratio with Photoshop, Lightroom or any other free editing program. We’ll talk more about this in a moment.

What are the most common types of aspect ratios or proportions in photography?

1:1 aspect ratio

Although there are many more, the most common formats or proportions in photography are:

1:1 or square. It is the only format that is not rectangular and has a fixed aspect ratio. There are few cameras that offer this format when taking pictures, except for some medium format cameras and some instant cameras. And it is that it is a somewhat unusual frame, although with the arrival of Instagram became very popular. Which does not mean that it is a bit complicated to use, then I will give you some advice about it.

2:3 aspect ratio

3:2 or standard. It is the classic that comes from 35mm film and the one inherited by all digital SLRs, both cropped sensor and full frame or mirrorless. Some medium format too. It is the one that corresponds to the most standard 10×15 print. In this example on the right, being vertical, it would be 2:3, since the longest side is the tallest. If you compare it with the next one, you will notice that the vertical is more marked.

It is the one you should use if you do not want to worry too much when sending them to print.

4:3 aspect ratio

4:3. They are the ones offered by Micro Four Thirds cameras and other digital cameras, such as compact cameras or those in mobile phones. It is a more natural and adaptable format to the eye. And it emerged to be displayed on the computer or television screen. It offers more space within the frame, there is no axis as dominant as in the 3:2 format. Although, unlike the square format, the proportion between height and width is enough for the brain to interpret it as vertical or horizontal and to place the gaze.

It is more used for viewing on a computer than for printing.

16:9 aspect ratio

16:9. This is the aspect ratio that is normally used for panoramic mode, although it is more of a crop, since it is not the proportion of any sensor (with some exceptions). Although the 16:9 ratio is the best known or most widespread because it is the one normally used by televisions, computer screens or mobile phones, as long as the longest side doubles the shortest (2:1 ratio) it is considered widescreen.

These last two aspect ratios (4:3 and 16:9) are closest to human vision and are the most commonly used on computer and television screens.

Let’s now see a horizontal panorama that is the most common, although there are also vertical panoramas. Here you can see how to get a panorama, beyond cropping, but now stick with how it looks in terms of proportions.

16:9 aspect ratio

In addition to these, which are more common or used, you can use other less frequent proportions but also standard ones or completely freely, without maintaining any type of determined proportion. Although, in that case, to print them you will have to go to a laboratory that will make them to measure for you or cut out all the white part that is left over from other larger standard formats, it is the option seedybut it gets you out of trouble 😉 .

How does aspect ratio affect photo printing?

In addition to affecting the composition, as we will see shortly, when you take or send a photograph to print, there are certain print sizes, for example, 10 × 15 or 9 × 13. If you send your photos without looking at the aspect ratio they have and choose one of the sizes they offer by default, you may be surprised that your photos are cropped somewhere.

That is why it is important that you take this into account. We are going to see how to make sure that your photos are not cropped at will, so that it is you who decides where to cut if necessary.

Here are the calculations that I mentioned above for divisions and multiplications, although I am going to make it easier for you with a table so you can see what standard print sizes fit the proportions of your photos. When sending to print, make sure that the aspect ratio (first row) corresponds to the print size, that they are in the same column of this table.

(1.78)5 x 5 cm9 x 13 cm 9 x 11 cm30 x 53 cm8 x 8 cm10 x 15 cm 10 x 13 cm50 x 90 cm10 x 10 cm11 x 17 cm 11 x 15 cm13 x 13 cm13 x 18 cm 13 x 17 cm20 x 20 cm15 x 21 cm15 x 20 cm30 x 30 cm20 x 30 cm30 x 40 cmPrint size and aspect ratio

Important: Paper size is measured internationally in inches (1 inch = 2.54cm), what happens is that in Spain, for example, this is changed to centimeters and when rounding there are (minimal) differences between the proportion and the printing, although choose the right one. For example, a 9x13cm is actually 85x127mm. This difference can be up to 5mm and the only way to avoid it is to always leave space near the edges, that is, not to leave something important in the image very close to the edge so that it is not eliminated. This is the actual size chart in mm:

Format in cmActual paper size in mm9 x1385 x 12710 x 13 95 x 12710 x 15 101 x 15211 x 15114 x 15213 x 18127 x 17813 x 17127 x 16915 x 21152 x 22820 x 30203 x 30520 x 27203 x 27013 x 13127 x 12720 x 20203 x 20330 x 45305 x 45730 x 53305 x 53350 x 90508 x 889 Correspondence of photographic sizes with real measurements of the paper in mm

Standard Photo Paper Measurements

If what you want is to print your photos at home and you don’t know what size to choose when buying paper because it comes in inches, this is the correspondence.

Cm910111320Inches3.5″4″4.5″5″8″Paper size in inches

Print size and minimum resolution

The resolution issue has nothing to do with the aspect ratio but with the print sizes. Each image size must have a minimum resolution so that the image is seen correctly and not pixelated. In other words, the quality of the print is indeed associated with the resolution. In this article we explain more about the resolution and other aspects to take into account when sending a photo to print, but I leave you with another table with the standard print sizes and the minimum resolution they must have. This is the minimum resolution, if it has more, nothing happens, if it has less, yes 😉 ).

Image size
)Minimum resolution (pixels)Image size
Minimum resolution (pixels)9 x 13700 X 100030 X 302400 X 240010 X 13750 X 100030 X 403200 X 240010 X 15800 X 120030 X 453600 X 240011 X 15900 X 120040 X 534200 X 320013 X 171000 X 150040 X 604800 X 320013 X 181000 X 160050 X 675340 X 131000 x 100050 x 766000 x 400015 x 201200 x 160030 x 534200 x 240020 x 301600 x 2400 50 x 90 7000 x 4000Recommended resolution based on print size

Anyway, when you upload your images to any photo development program, they usually give you a green, yellow or red face. This tells you if the resolution is optimal, adequate (although fair) or insufficient.

Aspect ratio and composition

As I mentioned before, the aspect ratio also influences the composition and how the images are perceived.

Composition in 1:1

A 1:1 aspect ratio produces balanced and stable images. These types of photographs are rigid and always lead towards the center. Also, they remove some of the background and space around or in front of the subject. In this article I offered you some tips to compose your photos in a square format. However, I leave you with some other ideas that you can take into account when using this format:

  • It is ideal for enhancing symmetries or when the surrounding space lacks information or importance.
  • By fitting a circle within a square format, you ensure that the attention and focus falls on the center.
  • The vertical and horizontal lines emphasize the sense of balance and stability that the square itself provides.
  • Diagonal lines are more dynamic than in rectangular formats.
Diagonals in 1:1 format

Diagonals in 3:2 format

Composition in 3:2

This format enhances the…