Here’s a recap of how to mock up your shirt design on a photographed model. You might need to tweak these steps if you’re working with a dark shirt.
- Find a good tee model. I’ll use a photo by Flickr user seventh.samurai from the Threadless Blank Tee Photos pool.
- We’ll need a grayscale version of the model to make a displacement map. Open the model picture in Photoshop, select Image → Mode → Grayscale. Bump up the shadows by pressing ⌘L and moving the middle slider. Save this as a Photoshop document. Hang onto it for later.
- Open the model image in Photoshop. Copy the Background layer and, using the polygonal lasso tool, select the t-shirt only.
- Click “Add layer mask” at the bottom of the layers palette to mask out the model and background. Hang on to this layer for later.
- If you need to change the shirt color, ⌘-click the shirt mask to load it as a selection. Click on the Background layer and press ⌘U for Hue, Saturation, and Lightness. Click the “Colorize” checkbox and play with the sliders to get the shirt color you want.
- Open your t-shirt design. If it’s in Illustrator, select the design and copy it to the clipboard. If it’s in Photoshop, select all your design’s layers.
- Paste your art into the model image in Photoshop as a Smart Object
(or, if the design’s in Photoshop, select its layers, press ⌘E to merge them, and drag the resulting layer onto the model image). Press ⌘T to change the size and placement.
- Play around with blending modes for your design’s layer. Depending on the design colors and the shirt color, different blending modes will look better.
- Select Filters → Distort → Displace. 3 is a good starting place for both settings.
Click OK, then select your grayscale model image. Your design should bend around the folds on the shirt a bit.
- Now to add the shadows back in: drag your masked tee layer to the top and set its blending mode to Multiply. Adjust the opacity to taste.
There you go! Fancy model in your fancy design.