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Transfer paper can be found anywhere you can buy stationary or printer paper. There are two types of transfer paper, one suitable for white or pastel shirts, and one suitable for all darker colors.  Most transfer paper is the same size as your regular printer paper (Letter size or A4 depending on your country). Before purchasing an unusual size, make sure your printer can handle it. Light transfer paper is used for light or white shirts.   Dark transfer paper is used for any shirt that is darker. You can use any image saved on your computer. If you only have the image in a physical form, scan it and save it to your computer as a jpeg file. Alternatively, take a photograph and transfer it to your computer. Transfer paper for light-colored paper creates a mirror image on your shirt. Look for a "reverse" or "mirror" setting in the print options window, or flip your image in MS Paint or another image editing program.  If you skip this step, all text in your design will be unreadable.  Do not reverse the image if you are using transfer paper for darker shirts. This type of transfer paper transfers the image exactly as it appears. If you're not sure whether the reverse setting worked, print out a test piece on ordinary paper. It should come out as the mirror image of the look you want. Before printing, check the preview to confirm that the image fits onto your paper. If it's too large, select "fit to scale" in the print options, or scale it down in an image editing program.  When printing with your transfer paper, you need the right kind of printer like an Inkjet printer.   If the two sides of your transfer paper look different, print onto the blank side. One side may have a logo, design, or thermal indicators on it. Switch to "landscape mode" if the image is wider than it is tall. Any paper you leave around the image will show up as a thin film on the shirt. To create a clean image, cut out the image. To get an accurate cut, use a ruler and an Exacto knife. Clear a table or countertop, then clean and dry it if necessary. Lay a cotton pillowcase over this surface, covering enough space to lay out the area of your T-shirt you'll be printing.  Most ironing boards are not suitable, due to the metal bars or grating on the surface. Use a surface that can withstand heat. Don't try to iron over a laminate countertop. A cutting board can also work. Check the instructions that came with your transfer paper to find out which settings work best for your product. If no advice is listed, select the "cotton" or high-temperature setting; select "dry" or turn off the steam; empty all water out of the iron. Give the iron a few minutes to warm up. For best results, use an iron with at least 1200 watts of power. ron the shirt. Place the shirt over the pillowcase. Iron it until it is completely flat. Any wrinkles will show up in the transferred image. Wash and dry the T-shirt first if necessary. If using transfer paper for light shirts, place the image face down. If using transfer paper for dark shirts, place the image faceup. Line up the center of the image with the center of your T-shirt neckline. Placing the image face down will allow the image to be transferred so that it’s not a mirrored image when it gets transferred to your shirt. Press the iron firmly over the clothing, pushing down with your whole hand for significant pressure.  Iron from 30 seconds to several minutes, according to the instructions that came with your specific transfer paper. Keep moving the iron and make sure to provide heat to every part of the paper. Some types of transfer paper have thermal indicators that will change colors when the area is hot enough. Let it cool for at least a few minutes, until the paper reaches room temperature. Peel off the paper to reveal your image underneath.

Summary:
Purchase T-shirt transfer paper. Select an image. Mirror the image for light-colored shirts. Print your design onto the paper. Cut out the image. Cover a hard, flat surface with a cotton pillowcase. Set your iron. . Place the paper onto the shirt. Iron the image onto the shirt. Let the area cool and then peel the paper off.