I’m no web designer but I’ve done quite a bit of modification for this site and these two little free tools help a lot.
The first one is JR Screen Ruler. It’s a small app which does just what you see. You can place a ruler, measured in pixels, anywhere on your screen. You can have it vertically or horizontally and you can adjust the length.
This image actually shows one ruler vertical and one horizontal. It will stay on top of all open windows. There are other screen rulers out there but this one has all the features I’m looking for.
The second app is Pixie. Pixie shows you a swatch of the pixel your mouse is currently over. It also gives you the hex, HTML, RGB, CMYK, and HSV values of the color making it easy to capture the color for reproduction in your favorite app. You can even hit control-alt-c to copy the HTML value for the color you’re looking at straight to the clipboard.
Thanks again to Zach (who is a web designer) for introducing me to these tools.