It's not easy to hold a camera in exactly a vertical or horizontal position. I was surprised to learn on a recent camera club shoot that some very experienced photographers continue to have the problem; I'm not alone. But sometimes we don't want a perfectly straight image because the tilt is part of the story. Whether and how plumb the image is to be is an aesthetic decision. Here is one of my favorite examples of an image that might possibly not be straight. (This poster is available.)
If we are going to change the tilt of the image we should do it early on in image processing.
What line in the image should be truly horizontal or vertical? In the case of the image we are working with, the answer is a little tricky since there is keystoning. I would pick the left edge of the window in back because it is pretty close to the middle and is least subject to keystoning. Separate instructions are provided for Elements and Photoshop.
