MTH 101: Aspect Ratios & Scaling

The word alone strikes fear into the hearts of many (OH, God, no! It’s MATH!! Aaahhhgggrrrrhh!!), after all, most of us wouldn’t have gotten in half as much time hanging out in the darkroom at the back of the Art Studio if we had actually GONE to Math class. As if!

But now we’re faced with another one of those things that we asked ourselves in high school “how in the world is this going to ever apply to me?” Well, lucky for you, we’re here to brush you up and even old Mr. Peters (or insert your own bushy browed math teacher’s name here) might crack a smile for you on this one!

Why do we need to know what aspect ratios are? Say you offer an album (or print) to a client and they come back saying that they want a couple smaller versions for their parents. What do you do? What size album or print do you pick?

I’ve seen it a lot: “Why is my image all smushed-up? I thought I could scale-down the original by taking an inch off each side? I only went from 11×14 to a 10×13. What happened?” What happened is that it just doesn’t work that way, and here’s why.

An aspect ratio refers to the relationship between width and height as a set. For every X units of width, there are Y units of height, and this relationship does not change when you “Scale” an image. So X:Y (said “X to Y”) is a marriage that can’t end in divorce. Even if you don’t use whole numbers or whole units, the proportional relationship stays the same. No worries, we’ll use a nice clean example to illustrate.

Squares have a 1:1 ratio. For anything square, the idea of subtracting the same amount from both sides would work, because a square has exactly one unit of width to every one unit of height. So no matter what number you take off one side, it will be the same number for the other side that will need subtracted as well in order to scale down without distorting your image. Easy, right?

Say you have an 8w x 12h photo:
4 is the largest number that can go into both of these numbers evenly, it goes into 8 twice and into 12 three times. So an 8w x 12h has an aspect ratio of 2:3 (two units of width to every 3 units of height). The units don’t matter, as long as they are the same. They can be inches or light-years, doesn’t change anything. The sides are dependent on one another, so if the height goes up or down, the width has to change also, not by the same measurement, but by the same proportion. So if our 12 inch height grows 1 more inch, the width, being only 2/3rds of the height, must grow 2/3rds of an inch or 0.66 inches.

An easy way to do a quick check to see if two things share the same aspect ratio and will be able to scale is to divide the smaller number by the larger number. 8×12 size comes out to 8/12=0.66 If two sizes both come out to 0.66 they are the same aspect ratio and are able “to scale”. So testing out a 4×6, you find that 4/6=0.66 and that means that you can safely scale down an 8×12 image to a 4×6 image without it being distorted.

We provide Size Charts for albums already arranged by compatible sizes under the DESIGN section on a product’s info page, so when you look at the chart, you can quickly see what other sizes are available if you should need to scale down and make a smaller copy of your original book.  Just a note on the Mixed Ratios, these are sizes that we don’t have another corresponding size for, so these are not able to be scaled down for our album purposes.

Well, now that wasn’t so terrible was it? Send all questions and apples to jamiew@finao.com and I’d be glad to further assist in any way I can!

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