Trying 85 lpi 4 color process

[cbjamel]

What mesh count is appropriate. 355 or into the 400's. Do I need to look at the extra strength's colors? Looking at more photographic type work. Is it 4.5 times the lpi? I do 55/65 in 305 now. What about Emulsions. I use Kiwo Poly One Coat now, do I need to look at something different? Anything else to look at??

Thanks for the help,
Shane
cbjamel at msn.com
Creations By Ja-Mel

[Dottonedan]

I can appreciate your attempt. In order to increase your chances at being successful, I would use 5 instead of 4 or 4.5 that would require a mesh that is above 400 mesh. You are really going to need to evaluate how much open area you have on a mesh that high. A real world method to determine if your highest mesh can hold the full tonal range is to take your smallest dot in an 85lpi screen ( between 2-3%) and see if it covers a single mesh opening and two mesh threads.

[Screened Gear]

I do 55/65 in 305 now.

Why the big jump from 55-65LPI to 85LPI? I am not expert on LPI but each LPI increase results in a lot smaller dot allowing more detail with each LPI added. If I was you I would take it in steps. If you can burn and get good results at 65LPI then I would try 70LPI. You should be able to hold up to 70-maybe even 75LPI with your current set up of 305s. I just wouldn't want to see you spend weeks and weeks working with 400 or higher screens and figuring out a new emulsion if another 5 or 10 LPI would get you the results you wanted.
 

[Sbrem]

I made the mistake of outputting films at 85 LPI for a job that we now print twice a year or so. 355 will do it, with a trade off here and there. We used to have some 420, but really just couldn't get plastisol through it well enough. Good luck.

Steve

[cbjamel]

Dan, what would be the best way to determine this.
Thanks,
Shane

[ScreenFoo]

Doing some quick and dirty math, at 85 LPI one "cell" for a dot is about 300 micron square, and isn't 3% @ 85LPI a less-than sixty micron dot?

[Dottonedan]

Doing some quick and dirty math, at 85 LPI one "cell" for a dot is about 300 micron square, and isn't 3% @ 85LPI a less-than sixty micron dot?

I'm not sure what you mean by 85lpi (cell). Are you referring to mesh opening or the cell used (in your printer) to plot out how many spits of ink onto the films in a given location to fill the needed space to make up a dot?

Most "digital printers" are not 100% accurate when outputting dot %. So, the typical digital films 85lpi 3% dots might be as much as 50% larger that a "real life" 3% dot.  Then again, what is "real life". I'm comparing to straight up traditional imagesetter films but those are almost all gone these days so the digital output results are our "real life. It;s like that old saying, "The one eyed man is king in the land of the blind".

The 420-30 Murakami smart mesh has a 30 micron thread and a 30 micron opening and results in a 25% open area (so they say).

Not that you'd measure this all that accurately, but your smallest halftone dot would have to be in the area of 2 mesh threads and one mesh opening to (get as much tonal range as you can get). That means your smallest dot (theoretically) would have to be 90 micron or larger.

SAATI carries a 420 mesh also, but it's thread diameter is 27 microns, with a 25 micron mesh opening with a 25% open area.

Now, once you've done that, you will realize that yes, your holding a very fine dot but then, what next?  Whats next is that as Sbrem sort of mentioned, your coverage would be very light (due to such a thin layer of ink) as well as most inks can't pass through the mesh easily. So, it becomes lacking in benefits to do so.

I'm not saying you can't, as I have in the past, but it's also just not production friendly.  I would not use that high of a mesh on all colors. I only use it when I might be trying to hold soft subtle detail on one or a few screens out of 8-12 colors. You can get great results of you had a 14-16 color press and was able to use all 420 mesh...but how often does that happen?

Those characters that say they are doing 85 and 120 lpi on tees are not giving you the full line of information. Yes, they are, but they are not holding under 10-15 % dot so they linearized the gradations. In other words,  what should be a 1% ends up being in the 10-15% place. They are using the mid tone of the gradations to build the art. You can do that (if you hav a big enough press) because what is actually the lighter part sof the art in a gradation (the range that visually falls under the 15% range) would end up being added on to another color that is lighter. Another spot color. That too, is made up between the 15-85% range.

Side note, When I was doing that high in my testing, I was using Kiwo. Not sure of what brand at the time.

[blue moon]

What mesh count is appropriate. 355 or into the 400's. Do I need to look at the extra strength's colors? Looking at more photographic type work. Is it 4.5 times the lpi? I do 55/65 in 305 now. What about Emulsions. I use Kiwo Poly One Coat now, do I need to look at something different? Anything else to look at??

Thanks for the help,
Shane
cbjamel at msn.com
Creations By Ja-Mel

 From personal experience, I can tell you that the linearized (calibrated with densitometer) 3% dot is the max one can hold on a 330S  at 65 lpi. I think holding 5% dot makes for a pretty decent print, but to be truly exceptional, you will have to hold smaller than that (linearized true 3% dot. As Dan already mentioned, before calibrating, the 3% dot was actually printing at 7%).

Murakami makes a 350S or something like it, maybe even a 380. My thinking would be to try those first at 75lpi and see what happens. If you send me your films, I'll take the readings and let you know what's coming up.

We use Murakami Aquasolv HV for emulsion and our fine meshes are coated at aprox 20% EOM. It turns out that with most things dialed in, holding a fine dot is not an issue. We tested some new emulsions last month and were getting 3-4% on 230 mesh at 55 lpi, but were hitting the threads and while emulsion was resolving, the mesh was blocking the smaller opening.

pierre

[Printficient]

We at Xenon can get you some screens or mesh in the mesh count ranges mentioned.  Give me a call.  Sonny.  404-895-1796

[tonypep]

Many insist that when you are this serious about resolution and detail, capillary film yields the most consistent results.

[Printficient]

Many insist that when you are this serious about resolution and detail, capillary film yields the most consistent results.

Agree 100%.  What light source do you have?

[Dottonedan]

I hear people tell me quite often that they are using a 55lpi on a 230 mesh and some say 65lpi on 230 mesh. As long as your dots don't fall under 7%-5% you should be good. If it's a fade off to the shirt, you will booger it up with the saw toothed affect.
I think I'm going to put this in my signature so its always visible.  I use 5 to come up with my optimum halftone. This way, it holds the smallest dot possible. If I've not held a 2-3% dot then it's something else that is wrong like,  emulsion, coating, exposure time etc.

Feel free to copy/paste:
330 mesh ÷    5 = 66 lpi halftone (rounded to 65lpi)
330 mesh ÷ 4.5 = 73 lpi halftone (rounded to 70lpi)
330 mesh ÷    4 = 82 lpi halftone (rounded to 80lpi) - Loss of dots below 5%, more depending on your shops capabilities.

305 mesh ÷    5 = 61 lpi halftone (rounded to 60lpi)
305 mesh ÷ 4.5 = 67 lpi halftone (rounded to 65lpi)
305 mesh ÷    4 = 76 lpi halftone (rounded to 75lpi) - Loss of dots below 5%, more depending on your shops capabilities.

230 mesh ÷    5 = 46 lpi halftone (rounded to 45lpi)
230 mesh ÷ 4.5 = 51 lpi halftone (rounded to 50lpi)
230 mesh ÷    4 = 57 lpi halftone (rounded to 55lpi) - Loss of dots below 5%, more depending on your shops capabilities.

Note:I will most often use a 230 mesh on my base and a 305 on top colors. I use the same halftone on all these days and will fit the 305 mesh, making all of the art at a max of 60lpi but more often I stay at 55lpi. Then, on your 230 mesh, you will eliminate most of your smaller lower end dots (but you want to usually) so that your top colors overlap your base white.

If I'm "required" to use a 230 mesh on a spot color job with halftones for example, I will not use higher than 45lpi (if the art has a soft fade to the shirt or to another color. It need to be a larger dot so that you can be able to hold it all and get that soft transition without the saw tooth.  Bigger dot, but smoother graphics. It's a trade off.

[tonypep]

A little off track but 60-65line process and sim process printing using discharge inks fool the eye into thinking its higher res as the dots "melt" in the steaming process. No dots visible to the naked eye or under a loupe.

[ScreenFoo]

Doing some quick and dirty math, at 85 LPI one "cell" for a dot is about 300 micron square, and isn't 3% @ 85LPI a less-than sixty micron dot?

I'm not sure what you mean by 85lpi (cell). Are you referring to mesh opening or the cell used (in your printer) to plot out how many spits of ink onto the films in a given location to fill the needed space to make up a dot?

The latter... in a way.  At 85 lpi, each line is approximately 300 microns-- 85x300 = 25500 microns, or close enough to an inch.  Just the way I make it easy on my head to do the math.    Great points on the output--transfer curves are fun, right?  That last bit of info is great--"Control without confusion" is the best book I've ever read on halftone theory and the range calculated in that example (which happens to be at 85LPI) is that 10-90% you speak of.   I suppose the trick you're describing would be similar to using a LM LC LY as well as grey to make that ten percent into a perceived one percent?

As to the match--A 90 micron dot relating to an LPI at 3% would be under 60LPI--at 85LPI it's over 7%--that was what I was getting at--don't you have to change the way you estimate your 'smallest dot'  to 'hold' these percentages? 

And isn't the real trick then what's on screen, as well as what goes down on the shirt?  Linearizing your printer is one step, but assuming you're not underexposing, you're dealing with dot loss at the exposure stage, and then gain again on press...

I (and I hope, everyone else as well,) really appreciate the great info the very experienced people here provide.   (Very neat info on the discharge, Tony)  I don't know about Shane, but I don't get to play with much stuff like this, but  I find it's a lot cheaper to fully understand the theory before I spend too much on testing--especially when it comes to expenses like the wisely suggested cap film...    

[RICK STEFANICK]

I made the mistake of outputting films at 85 LPI for a job that we now print twice a year or so. 355 will do it, with a trade off here and there. We used to have some 420, but really just couldn't get plastisol through it well enough. Good luck.

Steve

why not just re output the film?