mobile ruler for a photo file?

Factual Questions
1

I paint, often using photographs instead of a model, and it just occured to me that it would be helpful if there were some sort of measuring device I could move around in the photo to tell me quickly how far apart something is. (E.g., the end of the highlight on her nose is 3.293 inches from the furthest point on the left end of her mouth.) Is there some sort of movable device that gives quick measures of distance? I’m using Adobe Photoshop Elements to view my photos in.

I know I can use a grid, but that’s often mechanical and ungainly–I’m looking for something to give me exact measurements between two points just so I can be sure my sketch and underpainting is about correct, beyond eyeballing it.

Eyeballing usually works, but I ask because I just spent two hours painting a set of eyes and realized that this meticulously rendered detail work is off by about an inch–whole thing gets wiped out and done over when the canvas dries a little. Grrrrr.

2

I’m not familiar with Elements, but most drawing programs have a tool where you click to establish a first point & then can drag a so-called “rubber-band” line to any other point. Meanwhile, somewhere in a sidebar is a display with the current mouse location as x & Y plus the distance (& sometime direction) from the fixed point to the current mouse location.

That’s probably the easiest tool to use.

3

Google Earth has such a tool but I wish MS-Paint had it because it is extremely useful.

4

Have you tried using a grid? You can create guides in Photoshop, then comparable ones on the canvas.

5

Grids are a pain in the ass–counting squares, losing count, re-counting, re-counting again…I’d like some tool that tells me how many millimeters (inches, whatever) it is from pixel A to pixel B.

6

http://www.mioplanet.com/products/pixelruler/index.htm

7

Fabulous.

And one of them is free. Free and fabulous. Thanks.

Not to detract from the fabulosity or anything, but the free ruler seems only to work on the horizontal or the vertical plane. Is this correct? It would be superfabulous if I could move it around on various diagonal planes as well, though this is far better than what I had before.

8

Yeah, I think the one you have to pay for rotates but not the free one.

There may be other free rulers that do what you want. Those are just a couple I found a while ago. Here is a link to some other ones that might be better suited for your purpose:

http://www.freedownloadscenter.com/Best/on-screen-ruler.html