What are Aspect Ratios and Why Should An Artist Give a Crop About Them?

An aspect ratio is the ratio between the length and width of something. Aspect ratios are a shorthand way of describing the shape of things. In two-dimensional paintings, most aspect ratios describe rectangles and squares.

As a beginning painter, I never really paid attention to aspect ratios. I bought whatever boards or canvases were on sale. Size and shape didn’t matter because I was just using them to practice painting. Mostly, I thought of in terms of “small, medium, large, and too big for me to afford.”

When I began work on my artist’s website, I didn’t pay much attention to cropping the photos I took of my work—I just tried to get the entire picture in, even though it wasn’t exactly perfect in shape. I concentrated on accurate color and sharp focus, and some of my photos showed the edge of the painting (where the canvas started wrapping over the sides). And when I cropped photos in general, I only paid attention to what I wanted to include or omit. I never thought much about the measurements or the shape (i.e. aspect ratio).

Then I started shopping online for frames for my canvases. Eye-opening. Frames seemed to come in a limited number of shapes and sizes. Anything beyond that required custom mats and frames---much pricier.

But still, I didn’t truly put two and two together until I photographed my paintings and sketch book images and posted them to my website to sell as Art Prints. The platform of my artist’s website is called Artspan, and one of their services to their artists is they will mat and frame any of my prints for my customers. To take advantage of this arrangement, I submit a really good photo of an artwork and then they calculate what size prints they can make for me, based on that photo.

First of all, I immediately had many photos rejected because the imagery/colors in the painting didn’t “bleed” all the way out to the edge. No shadowy colors dropping off a rounded edge were allowed—All four outer edges had to be crisp and clean. (Note: This is true only in situations where prints are being made from the photos…Many artists prefer to photograph their paintings in a more natural setting, showing edge shadows and all.)

Second, I learned that if my photos did not have aspect ratios that corresponded to the most common frame shapes, it made it difficult to offer standard frames without losing part of my my painting’s details. While the clarity and pixel count of a photo are the major determinants of what size prints can be made, the aspect ratio also appears to play a role.

I realized that it was really helpful to learn about the standard aspect ratios found in many paintings and art photos, and that lesson is what I’d like to share with you now:

 

Here’s a diagram that I made showing some of the most common aspect ratios of two-dimensional art. 

The ratio is a number that results, in this case, from
dividing the shorter side by the longer side. If all four
sides are equal, the ratio is 1:1 = a square.

As you scroll down the page here, you’ll see that
as the aspect ratios get smaller, the black rectangles
get squatter (flatter). This can help when you’re trying
to figure out how to crop a portion of an image—an
aspect ratio of .80 is going to be much fuller than that
of .66, which is flatter by comparison.

If you have a good photo editing program, you can
ask it to automatically set the shape of your cropping boundaries.

For example, say you want a 3:4 (.75) aspect ratio.
   --According to the diagram at right, you could tell the crop tool to set the boundaries at
12 in and 16 in. The cropping box will have a .75 aspect ratio. Just enlarge/decrease the crop box and move it where it works for you.
 
  --If you want to work with pixels, start by dividing the smaller number by the larger. Examine the ratio decimal—if you’re within .005 of one of the common aspect ratios at right, you’re probably good to go.
So .714 is fine, and .805 is fine—just double-check with your print maker to be sure.

Note: the aspect ratios stay the same whether the picture is horizontal or vertical.

But what if you have a photo whose aspect ratio is, say, .78 (such as a photo that’s 2000 x 2560 pixels). That’s about midway between .75 and .80 (see above diagram). How you set your crop depends on whether you want an image that’s closer to square (.80) or one that’s a little squatter (.75). Examining the photo and deciding what’s most important to include (i.e., more width or more height) should help you make that decision. And, the shorter edge is going to be your “limiting factor.” Here’s what I mean:

This is a photo of my painting Soliloquy.
It had been rejected by my printers because I needed to clean up the edges.
    
Plus, it’s not perfectly square.
It’s 1781px wide and 1800px high. Before I clean up the edges, I need to figure out how to make it square (1:1). Ideally, it should be 1800 x 1800 px, but I simply don’t have the width—
I lost 19 pixels somewhere, probably because I tilted the camera a bit when I took the photo.
  
So that’s an important thing to keep in mind: the shorter side is always going to limit the final crop size. In this case, my final photo has to be a maximum of 1781 x 1781. I will set my crop size to that and dither about trying to include all the important bits.

Let’s go back to the imaginary photo you have that’s 2000 x 2560 pixels. Dividing the smaller number by the larger gives you .78. What if you want your image to have an aspect ratio of .75? You’d simply take the pixels of the longer side (to maximize the finished size of your photo) and multiply it times .75. In this case, .75 x 2560 = 1920. So your adjusted photo size would be 1920 x 2560.

If you wanted to go to a .80 (8/10) aspect ratio, you’re now INCREASING the height relative to the width, but you’re limited by your shortest side, 2000 pixels. So you’d have to solve the equation of 2000/x = 8/10. Remember basic algebra? Cross multiply 2000 by 10 (=20,000) and then divide by 8 = 2500. So you’d set your crop limits at 2000px  x  2500px.

Again, doing this sounds like a real challenge, but in the long run, you will save yourself (and your customer) cash if you/they don’t have to pay for custom framing.

p.s. You can also use the chart above for vertical paintings—just turn it on its side.
pps. If you'd like a copy of the diagram above, just email me at [email protected] and ask me to email you a .jpg or .gif of the diagram and I'd be happy to send it to you. Also, if you like my blog, I'd sure love to have you Subscribe--just click the link at the top right corner of this screen. Thanks!

Comments

[Joquim]

Interesting post! I never realized how important aspect ratios are in art. Your explanation was clear and easy to understand, making it easier for artists to grasp this concept. Two additional tips I'd suggest are: Experiment with different aspect ratios to see how they affect the composition of your artwork. Sometimes, a slight change in aspect ratio can dramatically alter the visual impact of a piece. Consider the final display of your artwork when choosing an aspect ratio. If you're creating a piece specifically for a certain size frame or canvas, make sure to choose an aspect ratio that will work well with that format. Overall, great job on highlighting the importance of aspect ratios in art.