When I moved into a new apartment, I started looking for something to fill up a blank wall. Searching around the site, I was inspired by kiwisaft's Instructable "Megaposter Curtain" to make a multi panel piece of artwork that would fill up my wall.

I didn't want to have any visible means of support, so I decided to use magnets instead.

Step 1: Materials

1] An image- It needs to be high resolution, or in a format easily enlarged without loss of quality.
2] Masonite- The amount you'll need depends on the size and number of the individual panels.
3] Spray adhesive- I know, I know, aerosol is bad...
4] Small metal washers- Something magnets can get a hold of.
5] Small rare earth magnets- I used 3/8" x 1/16" round nickel plated neodymium magnets, you might go a little bigger depending on the size of your panels.
6] Small level- To make sure nothing is crooked
7] Chalk line, or high tech equivalent- To ensure your panels are all evenly spaced.
8] Thumbtacks- If at all possible, get flat head thumbtacks so the magnets will stick better.
9] Chalk- To mark your wall
10] Glue- Something that will hold a magnet to the back of your Masonite. I used Gorilla Glue, but it expands quite a bit, so I don't really recommend it.
11] Tape Measure- To lay out your wall.

Might need:

Xacto/paper cutter- To trim up your printed images, depending on the size and whether or not you printed bleeds. If you use a print company like Kinko's, you could have them do the trim work, but they'll probably charge you for it.

Step 2: Your Image - Part 1

You can either do this yourself in Photoshop, or use the website Rasterbator, and have it done for you. I did it in Photoshop because my image is an unusual shape, and because I wanted to have more control over how it looked.

If you use the Rasterbator site os some other image editing software, you can skip to the next step, if you want to use Photoshop, read on.

I decided on a final image size of 6' x 2', which combined with 1/2 inch spaces between the panels, would cover a bit more than that on the wall.

First, I created a new document at an inch for every foot, so for my 6' x 2' piece, I created a 6" x 2" document at 600 dpi, CMYK, 8 Bit.

Paste your image, and size it so it fits the work area the way you want it to. You might have to crop it a bit depending on your image's size. Once your image looks the way you want it, you need to make it look more like a halftone image.

Duplicate your image layer, then apply a Color Halftone filter to the new layer (Filter>Pixelate>Color Halftone) I went with a max radius of 4, but you can go higher if you want more distortion. Then just drop the opacity of that layer down till you're satisfied. I went with around 30%, but once you're happy with how it looks, merge the layers.

Step 3: Your Image - Part 2

Once your image is finalized, you need to break it down into the individual sheets to be printed. To do this, I used an open source program called PosteRazor.

Save your image as a JPG, then change the JPG's mode to RGB (Image>Mode>RGB Color) For some reason, PosteRazor would save my CMYK JPG as all blank pages.

Then go into Image Size (Image>Image Size) and change the resolution to 100, and the size to the final size you wanted. In my case, it was 72" x 24". Save and open up PosteRazor.

Step 1: Select your image
Step 2: Input your individual image size, not the paper size you're printing on. Set borders to 0.
Step 3: Set this to 0
Step 4: Choose "Size in pages" and input your values. It should fit exactly, without any extra gray border.
Step 5: Click save and you're done.

Now you have a PDF, but unfortunately, if you have any white spaces like I do, you don't have any marks to tell you where to cut. So we need to add printers marks. The only way I know of is using Adobe Acrobat, so if you don't have it, you can ask your local print shop to do it for you when you take it in.

Step 4: Your Image - Part 3

Open the file in Acrobat, and open your PDF. Select Page Setup (File>Page Setup) and choose a paper size thats larger than your image.
Then select print (File>Print) and select the Advanced button. Then click Marks and Bleeds on the left, then check the box next to Trim Marks.
Lastly, make sure you have Adobe PDF selected as your printer, because we don't want to actually print it yet. Then print and save your new PDF.

Now you can print this PDF yourself or take it to a print shop. I took mine to Kinko's and had them printed on 11" x 17" cover stock. (I think that's what it was called, basically just a thicker paper)

You can print your images on anything you want, just make sure they print it at 100% scale, centered. It doesn't mater if they need to crop the white area around your image, but ask them to print out the first image to make sure everything is the way you want it.

Once you have them printed, either get them to crop them, or do it yourself, then you're finally ready to make something.

Step 5: Estimating Materials

I didn't give any quantities before because it depends on what you want to do. The number and size of your individual panels will determine how much hardware you'll need.

1) Masonite: Figure out the square footage your image will cover, then go to the store and figure out how much of each sheet of Masonite you can use. For me, it was 12 square foot.

2) Magnets: You'll need at least 2 magnets per panel, I used 3, but if I had been able to find flat head thumbtacks I could probably have just used 2. The larger each panel, the more magnet strength you'll need.

3) Washers: You'll need 1 for each magnet.

4) Thumbtacks: 1 for each magnet.

Step 6: Panels

Cut your Masonite into the size you want, or have someone at the hardware store cut it for you, and sand the edges a bit so they're fairly smooth.

Once you have them all done, wipe them down to get the dust off, and prepare to glue.
To help ensure that my prints went on straight, I made a little guide.

Just a piece of cardboard taped to a larger piece of plexiglass at right angles.

Spray a light, even coat of adhesive onto the smooth side of a panel, then place it against the corner of the guide. Then just slide a print against the left edge of the guide, and it should go on perfect every time. Make sure there are no bubbles of air, then let them dry.

Once the glue is dry, flip them over and glue a washer to at least the top 2 corners, at least 1 washer per magnet. For mine, I glued a washer to the top 2 corners, and 1 to the middle of the bottom edge, and I found it helpful to mark each one so I knew which way was up. Try to get all your washers in the same spot to ensure uniformity in hanging.

Step 7: Laying Out Your Wall

Starting from where you want one of the top corners to be, use your chalk line to lay out the top edge a bit wider than the final width of your piece including the spaces. Make sure it's level, then from the same starting point, run a line down the wall to give you one of the side edges, repeating for the other side.

Look at one of your panels and measure the distance between your top washers and the bottom edge of the panel, or if you have washers on the bottom edge, the distance between the top of the 2. This is the distance you need your guide lines for the thumbtacks to be. In my case, it was 5 3/4", so starting from the top of my side line, I would mark at 5 3/4", then 1" for the space between the panels, then another 5 3/4", then 1", etc... Repeat on the other side.

Once you have the sides done, you can mark across each line for where the thumbtacks will actually be. Measure the distance between the top of the top washers, this will be the distance you'll mark. For me it was about 11", so starting at the far side of the top line, I measured out 11", then 1" for the space, then another 11", then 1", etc...

Repeat the process for the bottom washer(s) line.

Now just push a thumbtack into each spot you marked, then wipe the chalk off the wall with a dry cloth. Place a magnet on each washer, and attach the panels to your wall.