How a paper bag is built
A paper gift bag is judged at the handle. That attachment takes the entire load every time the bag is lifted, and it is where a bag fails — usually by tearing through the paper rather than by the handle breaking. Board weight, reinforcement at the top edge and handle type are specified together from the intended load, and confirmed on a loaded sample.
How the handles are specified
Handles are the load path of the whole product. Attachment method, reinforcement at the join and handle drop are all specified from the intended load, and drop also decides whether the bag is carried on the shoulder or in the hand — the two need different lengths and are not interchangeable after production.
Confirm on a physically loaded sample, carried the way customers will carry it, rather than from a drawing.
The fabric
Paper weight decides whether the bag holds its shape when loaded and whether the handle attachment tears out. It is specified from the intended load rather than chosen by feel, and it should be confirmed on a sample loaded to the weight it will actually carry.
