Banksy Tenner, comes with COA, invoice and email correspondence from gallery. Authenticity guaranteed! I stand by this item.as.being authentic.Notice the square/octagon like dots under a magnifying glass in the last picture, this cannot be copied even with a high resolution scanner. Please contact me if you have any questions.Genuine tenners were produced using traditional offset lithography. The Tenners were produced using CMYK colours. Each of these colours will have had its own plate and printed separately. A close up of the tenner will reveal a rosette pattern. These cannot be generated via fake photocopies. Using a simple phone camera you can magnify the tenner. This will allow you to Cleary see the CMYK dots. I.e. C (cyan), M (magenta), Y (yellow) and K (black). This pattern is clear on the tenner and not blurred or non existent. It has its own plate, and each colour is separately printed in dots at a different screen angle. When done correctly, the overprinted dots form regular patterns, called rosettes. An authentic tenner must and will have a clear rosette pattern.