This question regarding continuous problems with tinting sounds very much like some experience I have had with web printing with EB inks. EB inks are quite similar to UV inks. ................................... Where I was working at the time, we had two presses which had little problem with tinting or toning. A new press was installed and right from the start there were problems with continuous tinting. The operators had to run extra water to try and keep tinting to a minimum but that was not a good solution. The tinting on the web increased as one moved to the trailing edge of the plate. ................................ All the presses had the same ink, same fountain solution and ran the same paper. It was found out that the cause of the tinting was related to the design of the dampener. That particular dampener applied too much shear to the ink on an inked roller and this ripped ink away form the ink film and resulted in small bits of ink in the free water layer that contacted the non image area of the plate. Since these bits of ink were small and were surrounded by the water, they would not reconnect with the ink layer on the form rollers. We did some tests to confirm this and could eliminate the problem but the test method was not suitable for a modification. ............................... We did this internally. The press supplier was useless and for over three years, they could not sort out the problem. Anyhow, this type of situation might be related to your problem. ..................................... On another related issue. Density control with EB or UV inks can be a problem due to how it interacts with water. Reducing the amount of water with an hot air knife can help but it is not the fundamental solution. ....................... There is a generic problem with all offset presses and it is related to how the press transfers the ink from the ink fountain roller into the roller train. Even on modern offset presses, there is not a positive transfer of ink. Water just makes this transfer process more inconsistent. ............................... There is a solution that does address the fundamental problem and that solution is to force the transfer of ink in a positive way across from the ink fountain roller to the roller train. This can be done in many ways but nothing is commercially available at this time. ............................ I have an invention called an Ink Transfer Blade or ITB which does force the ink transfer in a very simple and low cost way. It has a US patent(#6,857,366) and will shortly have a Canadian patent. It is not commercially available but the patent describes what it does. .............. The ITB has been tested on a web press with EB inks and on another web press with UV inks. Also a small sheetfed press. The testing also has been with coated, uncoated and plastic coated paper. .................... In all of these tests the water window is very large. The density is consistent and independent on how much water is applied. One can not wash the print out even if one greatly increased the water way outside the range one would want to use. The print density is consistent because the ink feed is consistent. The ITB does not solve every problem there is but it does solve a fundamental one and has shown that the major problem of density control is related to the press design and not the ink system being used. I hope this was of interest to you in thinking about your problems with printing UV inks.