Make all the art into a Photoshop file Kelly, Index colour is the best method to simulate stochastic and gives awesome results (no overprinting and very little gain) You do need quite a few printing heads to get a good result.
here’s a brief run down on how I do it, still in RGB, set the image size to 170 pixels/inch, go to image>mode>index color and you’ll get the index dialogue box, turn off preview and in "palette:" go to custom.
Remove all the colour index squares by clicking and dragging diagonally from one corner to the other, this highlights all the squares and you can delete them, now pick out the amount and range of colours you’ll need from the white squares, one at a time, as you click on them you’ll get a colour picker and you can eye drop from the image. when you have the 2,3, 4, 5, 8, 12 colours, whatever you need, save your colour palette, click OK and turn on the preview back at the index color dialogue box, you’ll now see the image as it will look in index, it may look crappy at 100% but zoom in and you’ll se how the image will print, if this is what you want then click OK and we can separate the index file.
I’ll run through that tomorrow if your interested.
Todie, Stevie,
thanks for the help/suggestions. I am temporarily on another project that came up i need to complete. I will be getting back on the stochastic project very soon and will look into your suggestions.
Stevie, i just might be interested in more once i am back on the project. Youll probably be hearing from me soon.
….."You do need quite a few printing heads to get a good result."….
I am unsure of the "printhead" situation. All my stuff gets printed in tiawan, so i am pretty disconected from that end. Sucks sometimes, it would be nice to be able to have comunications with the printer sometimes to help educate me. Is there something i should look for / ask about the printer about his print equipment?
Thanks again,
Is there something i should look for / ask about the printer about his print equipment?
Yes… whether or not they can do the stochastic screening in their rip, in which case you don’t have to do anything special, just prepare normal Photoshop and Illustrator files.
You said screen printing… silkscreen?
Steve:
So stochastic screening works OK in silkscreen? I would have thought that most stocastic would have too fine a dot for the silk.
So your method uses the dithered pixel structure of the indexed file, separating each of the colors in the table to a plate… interesting. In which case file rez would determine the dot size.
"So stochastic screening works OK in silkscreen?"
Yes, actually it can be quite popular with screen printing. Of course they use a coarser dot for silkscreen, not the fine dot used for offset.
170 pixel/per inch file size John (that’s what I use anyway, some people go to 220 or finer), way too fine for screenprinting in halftone with graduated dots (45-55 line halftone is most common in screen printing), but perfect on the same mesh with index/fake stochastic, the main benefit being no dot gain because there is no overprinting and the print remains sharp right throught the run.
You don’t put much ink down though so we’ve devised a method of putting a higly reduced (90% reducer) clear down afterwards to seal the "nape" of the shirt so after washing it doesn’t look instantly 5 years old.
I’ve done some award winning stuff using the index method.
Lots of print heads means lots of colours Kelly, at least 8, my stuff usually comes in at 12 -14 colours.
….lots of print heads… lots of screens… one for each color.
no overprinting.
yeah but wouldn’t that mean essentially kiss-fits between all plates that touch each other?
how do you avoid the need for trap?
I was always taught that silkscreening required pretty meaty traplines.
Some of the "heads" : ) are used as driers.
And all good printers can handle "butt fit" (as in butt up to each other) rather than overprinting. Lots of trapping is for crappy machinery, lowest denominator types, I don’t deal with them.
Well if we’re talking about silk screening, consider this scenario:
12′ banners, double sided.
In silk screen, one color hits first -cured, then the next color, and so on. Each ink hit, the substrate has to go through UV lamps to cure the ink.
Each time that substrate goes through the UV lamps, it shrinks a little bit.
So 4 color, both sides – that’s 8 times that banner is going through the UV lamps. (assuming it’s only 4 color – no spots/white or clear coat)
I’ve seen times where an 1/8" trap was not enough for this type of job.
Stevie is talking about T-shirts (10-12" wide images).
(What’s funny is that I’ve seen moire patterns on stochastic printed shirts : )
What’s funny is that I’ve seen moire patterns on stochastic printed shirts
Certainly not a screening moire…
Must have actually been in the file (pixel moire)
Even if there’s no moire in the image (and there could be), there could be fine lines that clash with the screen’s mesh angle, and (or) the T-shirt fabric’s angle.
Jason,
You don’t print off contact? I’ve never printed banners, but we did do some slick surface coated posters and off contact was used for each ink. Later we cured it under lamps.
"off contact"
I dont think so, because I have no idea what that is…?
We would always have problems with different substrates – sometimes the ink just didnt want to stick.
whatever it is – the site kills safari. it just simply fails to load, and takes safari down with it.
From that link:
When the ink can not be absorbed or penetrate the surface you wish to print, you can not lay your screen directly onto the surface to be printed or the design will blur/ smudge when printed.
The screen must be raised above the item to be printed by approx. 3-5mm, to create an ‘off contact’ style of printing. After your squeegee passes over the design area, and the ink is printed onto your item, the screen ‘snaps’ back upwards and the ink is left sitting on top of the item.
Yep, opened in IE to see what it’s about.
I can guarantee that’s how we printed. I’d say they had the screens at least 1/4" above the substrate.
There’s a lot of flex in a 96"x48" frame.
That’s why I do the 170 pixels/inch Todie, it’s a little coarser than most people like but I get no moire on 100 thread per centimetre mesh (about 230 tpi) and still get good coverage. I’ve seen terrible moire on or about 200 pixels/inch index.
Stevie,
I walked through your technique(explained at the top). I can see where that could be of help….(making mental note of technique). however, I am not sure if i can use it exactly.
The art that i produce (illustrator for 95% of the artwork, and photoshop only for the gradual blend) gets printed much in the same manner as mountainbike helmets. Its printed on a clear plastic and then formed into a shape. If my "dot" (stochastic) pattern is the least bit symmetrical, it creates banding really bad. The pattern/look i am needing to imitate (see webpage link for example) is the same as when you airbrush something using a "spatter" technique. Its a very random looking blend/gradient.
I included an example of previous art i have created (a mac stuffed file) called test2.sit which has an example of the red yellow blend created in photoshop that i currently use and have been using for produced product. I place the photoshop blend (the stochastic screen provided to me by an outside source) in illustrator.
An example of what i want to convert to a stochastic is posted on my webpage for anyone in a "helping" mood 🙂 called test1.sit.
<
http://kcrosby.home.texas.net/stochastic/stochastic.htm>
It has an internal drop shadow i wish to convert to a stochastic blend but don’t know how. I have tried several options, but not close enough to work…..or at least i don’t think they will work(this is where i wish i had the ability to communicate with the printer in taiwan). I don’t really have too much of an option to have him test different techniques. What ever i supply will be what it will be.
forgive any lack of printing knowledge……
thanking every one in advance for help……..
Jason:
Do you have the latest version ( v.1.2 ) because John’s link works for me in Safari?
No. I’m on 1.0 (ahh – I didnt even realize that!)
Maybe that’s the problem.
Hmm, looks like 1.2 only works in Panther?
Yep.
Time to change your spots?
Safari sucks. I’ll stick with Camino thanks.
Kelly,
I’d make the blend in two colors. Orange and Yellow (both blended to help eachother) at 1200ppi, as separate plates in bitmap mode (85 line screen halftone, round dot; the orange at 33° and yellow 63°).
Avoid 50% values, by making the orange blend 100 to 60% and the yellow 40 to 0%. Assemble in Quark or InDesign with the rest of the Illustrator EPS.
Just my 2 cents worth, I always use 55/63 for halftone work, all colours.
If it works, don’t change a thing.
