I have had several problems when trying to print designs with a black background that contain transparency. When I place a jpg into an AI file and change the blending mode to multiply to remove the background a gray box appears around it when it is printed. I have also removed the background in Photoshop and placed that file directly into Illustrator and the same problem occurred. This same problem occurs when using the outer glow effect. I have tried flattening it before printing it and that still doesn't help. I have tried converting to a PDF at press quality and that doesn't work. I have also tried using 100% black as the background and also process black. These files always look fine on screen. Please let me know if you can help.