Add border to photo but keep the aspect ratio same

[csrajput]

Hi,

I like to add borders to photos for which I have created few actions in photoshop. However for adding borders I have two options:
1. Add symmetric border (for e.g. 1" to all 4 sides)
For e.g. Picasa Web Albums - Charansing - Kelsey Creek ...
2. Add border in percentage of height width to keep the aspect ratio
For e.g. Picasa Web Albums - Charansing - NorthBend Trip

I like the first option because having similar sized borders to all sides looks better. However, this changes my original aspect ratio of the photo.

In second ratio since I use percentage method to add borders, the aspect ratio is maintained but if my photo's height and width are not same (like in 16:9) my borders are never of same size to all sides of the photo.

So my question here is: How can I add border to photo (in photoshop or some other tool) so that I maintain the aspect ratio but still get same sized border to all sides?

You suggestion on this is highly appreciated

- Charan
Picasa Web Albums - Charansing

[dcclark]

OK, I'm a mathematician, so I'll probably screw this up. :P

What you want to do is crop the photo into a nonstandard aspect ratio, so that when you use Option #1 (same size borders on all sides), the resulting image DOES have the right ratio! Here's an example calculation.

WARNING: Mathematical content ahead!

Let's say you have an image which is 2000x3000 pixels (that's 2:3 = 4:6 aspect ratio). You want to end up with something in the same ratio. So, you'll have to trim some amount off of both sides -- say, remove x pixels from the 2000px side, and y pixels from the 3000px sides. Then, you'll add the same amount (say, b pixels) to each side for a border. Then:

(2000-x+b)/(3000-y+b) = 2/3

This has many solutions (one equation with 2 variables and a constant, b), but we want the smallest positive values of x and y that make it work. So, first we get rid of the fractions:

3(2000-x+b) = 2(3200-y+b)

Solving for y, we get:

y = (1/2)*(3x-b)

So, you need to pick x to be the smallest positive number which makes 3*x bigger than b. For example:

If you have b = 300 (a border of 300 pixels), then y = (1/2)*(3x-300). So, x = 100 is the smallest that makes this work, and you get x = 100, y = 0. Then you can trim 100 from the 2000 pixel side, and 0 from the 3000 pixel side. When you add a 300px border, you'll have a 2200 x 3300 image, which is in the correct ratio.

SUMMARY:

For 2:3 ratio (most common on digital cameras), find the smallest value of x so that 3x-b is positive. Then crop x from the short edge, and y = (1/2)*(3x-b) from the long edge. Add a border of size b, and you're done.

You can do something similar for other aspect ratios.

Whew! I think I did it! :P

[csrajput]

Awesome!!!

Thats really wonderful explanation. But would I be able to add this in my actions?

- Charan

[dave_lines]

Not real sure if I understand what you are trying to do.. do you just want a line for a border around the outside of the image? If so,, you can use a stroke or you could add to the canvas size and make it however many pixels wide you like and whatever color you want. ie if you want a 10 pixel border, add 20 pixels to the width and height. DAve

[dcclark]

Originally Posted by dave_lines

Not real sure if I understand what you are trying to do.. do you just want a line for a border around the outside of the image? If so,, you can use a stroke or you could add to the canvas size and make it however many pixels wide you like and whatever color you want. ie if you want a 10 pixel border, add 20 pixels to the width and height. DAve

The OP wanted a border of a fixed size, as you said. However, if (for example) you add a 20 pixel border to a 2000x3000 image, then the new image is 2020x3020, which is no longer in the 2:3 aspect ratio. The OP wanted to find a way to add a border AND keep the right ratio.

Also, no clue about actions, sorry.

[OsmosisStudios]

You could also always add a border INSIDE the image.

In the 3000x2000 with a 20px border example, you'd end up with an image that was the same size (ie 3000x2000) but you'd also have a 20px border on all sides. That means you'd end up losing 40 px per side, but that's not that much in the grand scheme of things.

[dcclark]

Originally Posted by OsmosisStudios

You could also always add a border INSIDE the image.

In the 3000x2000 with a 20px border example, you'd end up with an image that was the same size (ie 3000x2000) but you'd also have a 20px border on all sides. That means you'd end up losing 40 px per side, but that's not that much in the grand scheme of things.

That's a ridiculously simple and easy idea! Come on man, we have to preserve the mystique of mathematics!

[wulf]

Inside would have been my choice as well (as much as the maths appeals!). Select the whole image and then shrink the selection by an appropriate amount. That will also mean the resulting image still prints at the same size for a given DPI setting.

If, of course, you really need a border in the first place. I'd rather leave putting on a border until when I am mounting and displaying the image for a particular purpose rather than embedding it in the image.

Wulf

[drr0b]

Of course an even easier way would be to make square crops of the photos... bloody mathemeticians over-thinking again!

[elkidogz]

Originally Posted by wulf

Inside would have been my choice as well (as much as the maths appeals!). Select the whole image and then shrink the selection by an appropriate amount. That will also mean the resulting image still prints at the same size for a given DPI setting.

If, of course, you really need a border in the first place. I'd rather leave putting on a border until when I am mounting and displaying the image for a particular purpose rather than embedding it in the image.

Wulf

I agree with Wulf here. I try to only put a border on images where either they make an impact on the content of the image, or it's going onto the wall. otherwise leave the image to stand to the edge of the file.