Half-fold

 

Z-fold

Piec is folded in half.  
half fold z fold

 

 

  

Four Panel Roll Fold

 

Tri Fold (aka, C fold, letter fold)

A type of fold where the piece is folded inward at one end and then folded inward again one or more times. It is as if you are rolling the piece up. A fold where a three-panel piece has both side sections folded inward, one on top of the other. Each section is approximately 1/3 the length of the piece. Also known as a C-fold or letter-fold.
four panel fold trifold
  

 

 

Quarter fold (aka French fold)

 

Double Parallel Fold

A sheet that has been printed on one side only and then folded twice at right angles to form a four-page uncut section. The diagram below shows a fold when the printed item is NOT being used as a self-mailer. A type of fold where the piece is folded in half and then folded in half again. The folds are parallel to each other. Also known as a quarter fold. 
quarter/french fold double parallel fold

 

 

  

Double Gate Fold

 

Gate Fold

Single gate fold, with an additional fold on the center. When both sides of an oversize page fold into the gutter in overlapping layers.
double gate fold gate fold

 

 

  

Accordion Fold

 

Half then tri-fold

A sheet that has been printed on only one side and then folded twice at right angles to form a W-shaped four-page uncut section. Standard Accordion folds are offered as 4-panels. For 5-panel Accordion fold jobs submit a custom estimate. Accordion folds are usually available on 100lb gloss book papers. Such as brochures and catalogs. A sheet is folded in half and then tri-folded.
accordian fold half then trifold