light color Opacity

[urbanrobot]

anyone have any advice for getting the most opacity out of a water based color? I need to print bright yellow on black paper and I need it to stay bright. The best advice I got was to mix the yellow with standard everyday sheetrock primer, but Im afraid of it gumming up the screen. is there any trick to this? I cant underbase it due to perfect registration purposes.

any advice is welcome. oh, and the search box yielded nothing.

[Gregory]

Print white underneath the yellow first.

[urbanrobot]

Gregory,

thanks, but I can't do that. I cant underbase because I'll never re-register the poster perfectly. the paper is always a little warped, and i have to pick it up to dry it - I need to get it opaqe in one shot. any suggestions?

[edwardo_machino]

You want an opaque yellow with a lot of pigment. I can tell you that I was able to do this with some flat yellow housepaint on a darkish paper, not black - can't remember what brand.

Maybe if you mixed it with some white primer, yeah. White ink should do the same thing. If you're afraid it will gum up the screen stop being afraid it will gum up the screen and try it. Another way - try printing once, drying the paper with a hair drier or heat gun, then printing on top. But this won't work very well if the ink is transparent to begin with.

[TeddyPancake]

I've heard some people print a whole flood of transparent base on the paper before any color goes down. That pretty much allows the paper to do whatever warping it will do before you start on the colors that need to be registered. Then you could do the underbase and have less registration problems. This adds two pulls to every sheet though. Adding white ink to the yellow would definitely increase opacity but makes the color push towards pastel. Maybe just use a coarse mesh and really heavy flood to push as much ink on the paper as possible.

[urbanrobot]

"Maybe just use a coarse mesh and really heavy flood to push as much ink on the paper as possible."
this is another suggestion I got that I like, which brings up another question: in your experience, what is the lowest mesh that you've used before you could see the edges? I only ever use 230. how low can I go and keep a crisp edge?

about the house paint, I've only ever used it successfully once. I dont know what the hell I did differently that time, but every other time, which was many, the paint gums up the screen - not dries - its weird. it just gets gummy and stringy in the little spaces on the screen, and on the edges of the emulsion.

Also I notice that if i get the sample size, it comes out thin like milk. If I open a gallon, its nice and thick. has anyone else experienced this?

[edwardo_machino]

Are you prepping the screen with a combination of 409 and water before you put the ink down?

[urbanrobot]

edwardo_machino -

... hold the phone - what?
hit me with that one in full please...

[squeegeethree]

Use white in the ink. From TW buy halftone yellow concentrate and ad some florescent saturn yellow pigment.

[strawberryluna]

If your off-contact is decent / high, you can just do two hits on press, one after the other. Flood > print > flood > print > remove paper and set the next one.

I've done that thousands of times with no ill effects. You just have to have some serious off-contact. I use a folded paper towel taped to the bottom corners of the screen to keep the screen well up off the press.