Screen Printers Open - A Forum for Screen Printing and Embroidery

Something I've always wondered about, having an idea about the correct way to do it, is printing halftones over a white halftone base. This seems very difficult to accomplish because, in my mind, the extremely small halftone dots of the top color must sit precisely on top of the underbase halftone dots. I can imagine attaining very good registration but underbasing a halftone leaves no room for any misregistration; no peeking allowed. The same concept has always made me wonder about how four color process being precisely lined up? Am I missing soemthing?

Not only something that must be accomplished with an underbases but also with a blend. This is I suppose what my problem is here. The first picture is what I wanted the print to look like. It was accomplished by printing an 80% underbase of white, highlight white, blue and red last. What I wanted to do was to print the underbasse, then blue, then red and the highlight white last to make sure the outlines were top dog (smell a trap?). The second picture is what I got when I did it that way. I think what happened was that a good percentage of the halftone dots ended up being printed on top of the blue and red dots and not where there was no red or blue ink like it should have. The scan I took (3rd picture) seems to confirm that.

Is it all a matter of registraion? Or do all things that I can think of that matter, very tight screens, perfect positives, tight press, and perfect registration all be requirements for any precision printing. Did I just answer my own question? I think I did. Precision printing requires precision. But then again, it's hard for me to imagine that all the successful halftone prints out there are only done by printers that use those requirements. So do the others use some kind of work around? That's my plan. I 'm gonna use a fifth screen with just the outlines on it. I'll get the results I want but probably not the proper way.

- Scotty

Homer, it's called a pellon, or test square.

I agree with Homer, I would have printed it the way you did the top one. Also, you should choke your base bask if you want to print halftones on halftones. Or, if you have problems lining that up, just do each as a spot color and print flash print each color on top of itself with high opacity inks. It doesn't solve your problem of not lining dots up, but it will make it easier in a pinch on a short run.

Your underbase looks larger than your overprint.

I'd have print it using a solid white underbase and process color using 55LPI with traditional angles and an elliptical dot.

The would i use to describe what is happening in the image is "strobing", this is where the registration of the press either aligns or doesn't align to other halftone dots. Traditional screens counteract this issue by the rossette being a controlled point of moire. Shift the screens around and the moire will shift with it, rather than strobing.

fred

Looks to me like you used the same screen (or film) for the highlight white that you did for the underbase. True?

If so, that, of course, won't work. If you're really going to use a highlight white, it has to be just for the areas to pop.

I still get good results by doing a P/F/P/F on the underbase white and wet on wet from there. No Highlight white.

Is the white supposed to show as an outline? If not, need to choke it back so the color lays just outside the white where the overlap splash will not show near as much as white does.

Just my 2c.

That is why I have damn near every color of wilflex ink. Most logos use the same colors, most reds are either national or dallas scarlet. Most navys are bears or regular navy.

The problem with process is if you have to reprint a color that ran out of ink or somehow didn't print right, you end up with a funky shade.

This is a spot job all the way.

Do ink shops not ship to Dahlonega?

Looks to me like you used the same screen (or film) for the highlight white that you did for the underbase. True?

If so, that, of course, won't work. If you're really going to use a highlight white, it has to be just for the areas to pop.

I still get good results by doing a P/F/P/F on the underbase white and wet on wet from there. No Highlight white.

Is the white supposed to show as an outline? If not, need to choke it back so the color lays just outside the white where the overlap splash will not show near as much as white does.

Just my 2c.

No, the underbase is not the white you see. It was a separate white screen.
Yes the white outline is important since these will be printed on navy shirts.

Two completely different films were used for the underbase and the highlight white. The underbase all 80% halftone. The highlight white is the halftone blends and the outline.

Thanks for all the responses but I am still looking for an answer as to whether or not a nice blend can be done without the parameters I mentioned before. Imagine blending white into red. The halftone dots of each color will have to precisely fit into 'holes' not filled when printing the other color. Can this be done without very tight screens, perfect registration, an accurate press, and perfect positives? And if you don't have these conditions then should a printer come up with a different way to print it? And what about four color process? If you don't have the conditions is it even possible? - Scotty

Hold the phone! Evidently I am not correct in my understanding of how these colors merge. As I explained before, I imagined holes left by one color being filled in by the other. If this were the way it worked then layering a positive of one color on top of the other should result in the object of the blend being completely black with printer ink, assuming the colors of the blend started out as 100% at their non blend ends. So I got a surprise when I lined up the blue positive over the white positive. All the dots of the blue lined up right on top of the dots of the white. Now I'm thinkin' that there is no way to get a decent blend other than printing a halftone fade over a solid color. What do you all think? - Scotty

Two completely different films were used for the underbase and the highlight white. The underbase all 80% halftone. The highlight white is the halftone blends and the outline.

Thanks for all the responses but I am still looking for an answer as to whether or not a nice blend can be done without the parameters I mentioned before. Imagine blending white into red. The halftone dots of each color will have to precisely fit into 'holes' not filled when printing the other color. Can this be done without very tight screens, perfect registration, an accurate press, and perfect positives? And if you don't have these conditions then should a printer come up with a different way to print it? And what about four color process? If you don't have the conditions is it even possible? - Scotty

Hold the phone! Evidently I am not correct in my understanding of how these colors merge. As I explained before, I imagined holes left by one color being filled in by the other. If this were the way it worked then layering a positive of one color on top of the other should result in the object of the blend being completely black with printer ink, assuming the colors of the blend started out as 100% at their non blend ends. So I got a surprise when I lined up the blue positive over the white positive. All the dots of the blue lined up right on top of the dots of the white. Now I'm thinkin' that there is no way to get a decent blend other than printing a halftone fade over a solid color. What do you all think? - Scotty

I think not. All my underbases (under colors) on halftone prints are halftones themselves. Solid white (not underbase) is solid white.