Although our Standard White Direct Thermal (DT) is not a transparent material, it is not considered a blockout material. Depending on what's printed it may cover an existing barcode. You're welcome to try free samples at the following link to test: https://www.onlinelabels.com/samples However, we do offer the Blockout for Laser (BT) at the link below. The BT material is a sheeted material with an opaque, gray underside intended to block text and images. https://www.onlinelabels.com/materials/blockout-laser-labels