This is a nice, basic article that comes from Popular Mechanics. It explain the picture hanging basics. I have added the following two items to their content.
1. Get a piece of Museum putty, from a shop like Michael's. Once you get the picture placed and level, a very small piece, size of a dime. on the bottom center of the picture will keep it from moving.
Don't worry, it is wall and paint safe. Just keep it clean.
2. An inexpensive Lazer Level is invaluable in keep all the pictures in a room at the same level.
POPULAR MECHANIC'S ARTICLE:
Although it's a simple DIY project, picture hanging can be frustrating if you can’t get the frames where you want them (and potentially expensive if you knock holes in the wall).
Hanging a picture on a wall is arguably the simplest of all DIY home-improvement projects. In fact, it’s almost impossible to do it wrong. Almost.
As with most things, there’s a right and a wrong way to hang pictures. The most common problems include hanging the picture securely so it doesn’t fall, pinpointing the nail location so the picture hangs exactly where you want it, and hanging it perfectly level.
There’s no single, surefire way to hang every picture. But here are several tips that can help you hang virtually any frame as perfectly and precisely as an art gallery.
When hanging a picture, it’s best to drive the nail into a wall stud for superior strength. But chances are you’re not going to. Studs are typically spaced 16 inches on center and are only 1½
inches thick, so the chance that a stud will be in the same place where you want to hang your picture is remote—you’re much more likely to tap the nail into a void between two studs. And for
small- to medium-size pictures, that’s okay.
A single 1 1/2-inch (4d) or 2-inch (6d) finishing nail will support most pictures, even when nailing between studs. The trick is to drive the nail into the wall at a steep angle, at least 45 degrees. That will provide much greater holding power than tapping the nail straight into the wall.
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Another option is to use a picture-hanging hook, which comes with its own small-diameter nail. These specialty fasteners come in a wide variety of sizes and are surprisingly strong—if properly installed. First, insert the nail through the sleeve on the hook, then hold the hook against the wall at the desired height. (The hook automatically aligns the nail at the optimum angle.) Next, tap the nail all the way in. Just be careful not to strike the hook, or it’ll cut into the wall.
Generally screws provide more holding power than nails, so they’re better for hanging large, heavy pictures. When hanging a picture between studs, use a hollow-wall anchor, such as a toggle bolt, molly bolt, or spiral anchor. A spiral anchor is the easiest to install: Simply drive it into the wall with a screwdriver, then drive a screw into the anchor. Some spiral anchors come with special picture-hanging hooks.
We’ve been there: You’re staring at the wall, trying to figure out where to you need to drive your nails so your pictures hang in just the right, pleasing spot. Here are two quick, effective methods for figuring it out.
Method 1: Hold the picture against the wall at the desired height, then draw a short pencil line on the wall that marks the top of where the picture will go. You don’t have to draw all the way across the top of the picture—just make a short line at the center.
Take down the picture; hook a measuring tape onto the hanging wire attached to the back of the frame (or whatever will be sitting on the nail to hold up the picture). Pull the wire tight and measure the distance to the top edge of the frame. Now simply measure down from the pencil line on the wall that same distance, mark the spot, and drive in the nail. If you’re using a picture-hanging hook, make sure the hook—not the nail—is level with the spot you marked.
Method 2: Make a simple picture-hanging tool from a wire clothes hanger. First, use pliers to cut a piece of wire about 12 to 14 inches long. On one end, measure in 3 to 4 inches from the end of the wire and bend it down at a right angle—this will be your handle. On the other end, bend the wire in the opposite direction to form a 1-inch-long leg. Snip the very end of the leg at an angle, creating a sharp point.
To use the tool, hook the short, pointed end under the hanging wire on the back of the picture. Hold the picture in position using the wire handle. Press on the picture with the palm of your hand. The pointed wire end will pierce the wall, indicating exactly where to tap in the nail.
Be sure you know how to use a level to get the picture to hang straight. If you pictures don’t stay level, try this simple trick.
Go to a home center and buy a package of small rubber bumpers, the kind with peel-and-stick adhesive backing. Take the offending picture and place it facedown on a covered surface. Stick one bumper onto each bottom, rear corner of the frame, then rehang the picture.
The rubber bumpers will provide a little traction and help hold the picture straight and level. And as a bonus, the bumpers create airspace behind the picture, which prevents dust and dirt from collecting and creating “shadows” on the wall.