DuraFirm Technology Bulk Inks for Uni-Kit Featuring COLORFAST INK For those who have refilled before and just need INK! Our 60ml, 250ml and 1 gallon bulk ink packs save you even more money. The Uni-Kit bulk ink bottles come with DuraFirm Technology (Colorfast Ink), which has archival qualities (does not fade), is smudge resistant and waterproof on waterproof paper! These inks are the latest technology and 100% guaranteed to perform and last longer than your original manufacturers ink! Colorfast ink is archival quality. The ink wont fade or more accurately in time all things fade. In this case the fade is on tone. The result is that it takes about 3 times longer to see the fading. The ink wont run when used on waterproof paper.