Making math look good: advertisement photoshoot for a calculus course

Last summer, my wife was involved in designing a short course in calculus for incoming first-year students at UVic. To help promote this course, we set up a staged photoshoot with current students and instructors as models. Armando and I set up the lighting (studio strobes with softboxes and umbrellas) in the actual classroom where the course would be taught. We had a relatively short shooting list: couple of shots of individual students writing on the board, a group portrait of them having a conversation in front of the board with formulae written on it, and a group portrait of the students talking to the instructor.

The key image, shown above, is a composite of two photos: a shot of the student pretending to be writing (he was holding the marker in mid-air) and a shot of the math formulae written on a white board with a blue marker.

Here is how I made it:

• Opened both photos in the same Photoshop document: the portrait on the background layer and the shot of the board on the layer above it.
• Created a Curves adjustment layer above the top layer.
• Clipped the adjustment layer to the layer below it. To do it, I clicked the left-most icon at the bottom of the Curves menu, which looks like a square with an arrow pointing down. This makes the adjustment layer affect only the layer immediately below it, not all underlying layers.

• Increased the exposure (by dragging the midpoint of the curve in the layer menu upwards). The purpose of this is to over-expose the image of the white board, so that everything, except the text, becomes solid white.
• Selected the layer with the board image, and clicked on the white colour with the magic wand selection tool (activated by pressing W). I held Shift key and click inside all areas enclosed by the blue lines, such as the areas inside the loops of 6’s. This created a mask containing everything, except the blue text.
• Pressed Delete key. This removed the white board and left only the blue text.
• Removed the selection by going to Select > Deselect in the top menu bar (or pressing Command-D).
• Selected everything in the layer (i.e. the text) by going to Select > All (or pressing Command-A).
• Went to Edit > Transform >Flip horizontal to create a mirror image of the text.
• Selected the move tool (by pressing V) and dragged the image of the inverted text to align it with the marker in the student’s hand.
• That’s it! I saved the  Photoshop document to preserve the layers. The flattened composite image can be saved in any format afterwards as a copy.