Message
RE: I've only just found QTR
2013-12-17 by <sanking@...>
I have been making digital negatives for UV sensitive alternative printing processes for the past 12-15 years and have tested many inksets. I don't believe it is generally correct that the color inks block UV better. In fact, with all of the current large carriage Epson printers that use the K3 inkset MK is by far the biggest blocker of UV light. PK blocks about the same as Y and C. G in the *900 series printers also blocks a lot of UV, about like C+Y.
You can test this by printing the ink calibration page in QTR, using calibration mode, and then either reading the densities with a UV densitometer, or by printing the page with a UV sensitive process. What you will find is that UV blocking is in this order:
1. MK
2. PK
3. Y
4. C
5. LLK
6. LC
7. LLK
8. LM
G in the *900 series also blocks a lot of UV, not sure where it falls compared to the other inks as I have not actually tested it.
I don't know what UV blocking one needs for printing circuit boards but at 100% the blockage of the MK in the Epson K3 inkset is about log 4.5, and Shade 1 in the Cone K7 set blocks as much or more. That much density gives what we might call a bullet proof negative.
Sandy