Placing Guides for a Classic Tri-Fold Brochure (C-Fold or Letter Fold)
This fold creates three panels by folding the right panel inwards and then folding the left panel over it.
For even folding, the inside panel (the one folded in first, typically the right panel) needs to be slightly smaller than the outer panels to prevent bulging.
Guide Placement:
Outside: Place guides at 3.625" and 7.313" from the left edge. This creates panels of 3.625", 3.688", and 3.688".
Inside: Place guides at 3.688" and 7.376" from the left edge. This creates panels of 3.688", 3.688", and 3.625".
Note: The exact measurements can vary slightly depending on paper thickness and folding equipment, but a common rule of thumb is to make the inner panel 1/16" to 1/8" smaller than the outer panels.