Linen backing is a key step in poster conservation because it stabilizes fragile paper, flattens waves and folds, and gives torn or brittle sheets safe, even support. A properly backed poster is easier to handle, frame, and store, and it can slow further damage from stress and humidity changes. But quality matters: the right tissue, paste, and tension must be used so the work stays reversible, avoids stains, cockling, shrinkage, or distortion, and respects the original print.