Invisible UV ink for inkjet printers - 10 ml bottle Blacklight invisible ink Print real fluorescent images and see them only under a 365 nm UV lamp (the ink reacts THE best at this nanometer lenght) Very simple to use: You`ll need a inkjet printer, empty refillable ink cartridges. Fill your empty refillable ink cartridges. Place them in your printer and you could start to print. The effect will be amazing. Application : - secure documents, labels, images; - invisible decorations in homes, bars, hotels, restaurants (posters, wallpaper printed invisibly on the walls); - safekeeping of brand authenticity; - marking cords, badges or any cotton white material; - unique customization of your brand; - keeping your secret images on clothes, mugs or any sublimation stuff; Note: This ink is only suitable for printers that have a piezo printhead. Recommendation! - using invisible ink with compatible inkjet printers and rechargeable cartridges; - use a UV lamp with a wavelength of 365 nm (the ink reacts best to this nanometer intensity); - print must be made on non-fluorescent materials. Paper selection : please be aware that most of the white copy paper have fluorescent brighteners to make the paper look whiter. These brighteners are usually fluorescent blue and the invisible inks can be hard to detect on bright white paper .So it 's highly recommended to use papers without any optical brighteners.So for best results we recommend non-fluorescent paper. Black light : a black light , also referred as a UVA LIGHT , wood's lamp or simply ultraviolet light is a lamp that emits short wave UVA, ultraviolet light and not much visible light. For our invisible inks black light with 365 nm is the optimum.