How to do light painting using Nikon d3100?

I just bought my first SLR. I'm trying to learn photography and trying to learn the light painting technique. I have been to Google and went to YouTube for some answers but still I remain unsatisfied and failed to do my light painting. Please can anyone help me?

Dark setting. Long exposure on your camera. Run around with a light stick or flashlight. Don't stand in one place for too long if you don't want to show up in the image. You may have to experiment with ISO and aperture in order to get a sufficiently long exposure without overexposing everything. Try different exposure times. Keep records.

All these tutorials expect you to have a basic understanding of the exposure triangle, and for you to at the very least be able to use the camera in shutter priority (S) mode with exposure compensation. You need to first get the exposure you want without painting light. Then add in the light you want.

There's quite some skill involved to get anything complex as you need to learn to draw everything mirrored left-right, as you need to face the camera and you won't be able to see anything you've done until you look at the image recorded. If you find that doing everything backwards is a little confusing, you may find it easier to project a laser pointer onto a wall and paint using that. This allows you to be able to draw things with greater complexity.

Whatever method you choose, light painting requires well developed spatial awareness and hand eye coordination as whatever you paint is invisible to the eye, and therefore you need to know where you've been with the light.

You have completely read the owner's manual so that you understand the effects of shutter speed, aperture, and ISO completely right?

What's that? You haven't? Well, then I guess you better start reading…

You would usually set the cameras shutter to B or T, lock it open, then run around with a light and paint the walls or objects with the light, then close the shutter.

Experiment, have fun.

There's a whole cult of this on Flickr look out for a guy called 'ernegon' and follow his friends; one Spanish 'school' uses several high power floods to great effect, you need well trained assistants for the grander son et lumiere effects on such as a big castle. Plainly, a bulb setting with the release locked open, we're talking minutes unless there's still light in the sky (which is usually a help to composition of large object). Do not ramp up ISO, you will have noise troubles, use middle apertures and long times.
Plainly, the camera is not program scene or automatic mode, pure manual. Start by taking a collimation shot using the light you have, try 30 seconds say and paint a small wall. Check histogram. Expend the time or reduce according to where the histo' is bunched, try again. Once right (highly subjective) then aim at your subject and get cracking with the light.

Try and get a very long exposure - in minutes; that way a ten second error has no effect, whereas a quick exposure has to be more exact. That's why you chose a middle aperture, apart from it'll be the best the lens can do (apologies Z€i$$ users and £eica lenses)

Have fun

Light painting is fairly simple if you understand how to use your camera. You first have to understand that the larger (the lower the number) the aperture, the more light is allowed into your camera, so usually if you're shooting in the dark you want the largest aperture possible. However, with light painting you need to use long exposure, meaning you use a very slow shutter speed. You'll need to use your camera on Manuel mode, and reduce the shutter speed to the Bulb setting. This allows you to keep the shutter open for as long as you keep the button pressed down. Some cameras have a lock so that you can move away from the camera, but you may need to purchase one instead. I got a shutter trigger for my Nikon D80 for things like self portraits, which allows you to lock your shutter. You'll need to set your camera on a tripod and use bulb settings for long exposure - the longer you leave the shutter open, the brighter the image will be, which means you'll need a small aperture (f11-16 probably), otherwise your image will end up over-exposed. Using a dark room and a small light source is best to practice with, with a low ISO (again to reduce over-exposure) and a low aperture. Practice by drawing small shapes etc at first. The faster you release the shutter, the more likely that your body will appear in the photo, therefore it's best to completely remove yourself from the photo for a couple of seconds before releasing the trigger. After you've mastered the basics you can try longer exposures and use multiple light sources etc.