I want to create an action that will place a border around a photo. The question is, do I create it as a percentage of the photo size or as a fixed number of pixels? I want the border to be relative to the original photo size. IOW, I don't want an 800x600 photo to have a 10-pixel border and a 2400x1200 photo to have the same size border. I hope this makes sense. Any help will be appreciated!
Because Images canvas can have any number of pixels and have any aspect ratio both portrait and landscape wide panoramas and tall skyscrapers same percentage of what? You could have an action add like 1" of canvas to the width and height how many pixels that would be would depends on the image print resolution setting. The action will just record relative and add 2" to the width and height. Photoshop will add the canvas based on the document print ppi the add the 1" boarders. It is easy for actions to add canvas for mats and frames.
If you want relative border dimension then set Ruler to Percent when recording action because there isn't (for now) conditional action to check dimensions and react based on condition/dimensions but you can check for orientation if necessary. The only way is using Percent or perhaps using custom script what is not an easy solution.
The thing is Aspect ratios vary and a percentage of the width and height will create uneven boarders on none 1:1 aspect ratio that vary with an image aspect ratio using Canvas size. Using a modify border would you would need to use a percent of what the step requires a number of pixels you can not use percentage or a relative unit like inches. It requires an absolute number of pixels you want the boarder to be
That is right if aspect ratio is different. I can not even remember how to record action to calculate border width instead of using fixed number, long time I haven't deal with border actions. Will check later, generally for anything that is not fixed, solution is manual input or step recorded with percent as measurement unit.