White underbase question

[vicb]

I was printing out some seps and wondered what the result would be if I printed the white underbase at 35 dot frequency 22.5 degrees and
the top colors at 55 dot frequency 22.5 degrees. Not sure how the print would look and if there would be a pattern in the print.
Has anyone who has tried this and what were the results?

[3Deep]

Grainy, but a pretty cool effect if your going for that, but will smooth out some as the white base starts to fill in if you PFP your underbase.  Your cymk won't be as bright printing on a 35 % base if your printing on dark unless you us triple blend, I've heard it work much better than the regular cymk inks that I use.

Darryl

[blue moon]

if you print at two different angles you will get moire (a hatch like pattern). There might be some designs where you can get away with it, but for the most prints it's a no, no!

try going to 45lpi for everything and putting the ubase on an S (thin) mesh. 225S would be good, it should even hold your 55lpi just fine.

pierre

[vicb]

I just used the 55lpi art and burned it on a 156 mesh screen. I cut the exposure time down to eliminate 99%
of any moire' pattern forming. It burned fine with no pattern and I just re-exposed it afterwards since it was initially
underexposed. I usually don't burn a 55lpi screen on 156 mesh but I think it should print just fine.

[kirkage]

I am down with the "flexo" angles  22.5,  37.5, 52.5 etc.

[Screened Gear]

I just used the 55lpi art and burned it on a 156 mesh screen. I cut the exposure time down to eliminate 99%
of any moire' pattern forming. It burned fine with no pattern and I just re-exposed it afterwards since it was initially
underexposed. I usually don't burn a 55lpi screen on 156 mesh but I think it should print just fine.

55LPI will not hold on 155 unless it has no gradients. Especially if you lower your exposure. I am not saying your wrong here, maybe you know something I don't. Did any detail wash off?

[vicb]

It burned just fine and lost no detail. Just lower your exposure time by 1/3 and give it a try.
If you burn it at the regular setting, you will get a nasty pattern and lose detail.
The underbase was a negative reverse of the full color image converted to a grayscale.
I was trying to use a lower mesh because the design also had white text.

[Screened Gear]

It burned just fine and lost no detail. Just lower your exposure time by 1/3 and give it a try.
If you burn it at the regular setting, you will get a nasty pattern and lose detail.
The underbase was a negative reverse of the full color image converted to a grayscale.
I was trying to use a lower mesh because the design also had white text.

Can you take photos of the screen? What exposure unit did you use? 55LPI will have dots way to small to hold on a 155 threads per inch screen. Highest I can go on a 155 is about 45LPI and that is not easy. I have to burn longer to hold the stand alone dots. A shorter exposure time would never hold the dots.

[GaryG]

I can see on the outside chance with s mesh, but that is pushing
the limits of simple math. Mesh being the defensive line and dots the fullback.

[jvanick]

so I know this is a bit off topic, but in the same realm...

how do guys like Artem hold 150lpi halftones on a 300mesh screen (according to the #'s it should be impossible, just like 55lip on a 150mesh)?

[3Deep]

so I know this is a bit off topic, but in the same realm...

how do guys like Artem hold 150lpi halftones on a 300mesh screen (according to the #'s it should be impossible, just like 55lip on a 150mesh)?

I'd like to know that too since I'm thinking that 150lpi is darn near solid

[ScreenFoo]

Depends on the tonal range of the original you're trying to hold. 

Just about anyone can hold 25%-75% @ 55LPI on a standard 160, I doubt too many can hold 10%-90%.