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Mojorocker1964
Participant
April 9, 2009
Answered

Silk Screen and Halftone dots

  • April 9, 2009
  • 7 replies
  • 58874 views

What is the short answer to, "Can Illustrator allow the user to control the size of halftone dots?" Just to be clear, for silk screen, the dots must be course. I have read several posts on the subject and still there is no definitive answer. The PPD file has been loaded. The document is a CMYK. In the print menu the separation menu has only very fine settings available (The lowest is 56 lpi/300dpi) which if selected makes very little to no difference in the dot patterns.


     Just to reduce confusion, often a silk screen printer will try to get two colors for the price of one. The simplest example would be to get Black & Gray with one screen. If I set the Gray to 50% and the Black to 100%, still no change. If I use spot colors like PMS Cool Gray and Black, no change. Moving the files into Photoshop may work but fundamentally speaking PhotoShop in my opinion is for constant tone images or Photos, and it seems counter productive to add in a extra step (and software) to the work flow.


     I like to stick to the old K.I.S.S. motto. Keep It Simple Stupid. In this case less is better. Other software packages make this task a no brainer. I like Illustrator and have invested hundreds of hours learning and promoting it's virtues. When I was asked by a local shop how to do this task, I responded, (Oh I'm sure its just a setting that needs to be set.) Well, not so. So, Can I do this or do I need to tell my associate to keep using CorelDraw! 7...

    This topic has been closed for replies.
    Correct answer Skullmaker

    Hello Mojorocker1964,

    Adobe Illustrator gives the freedom to output the artwork at any LPI or DPI you wish (The Typical LPI for offset printing ranges from 85-133 lines per inch)

    The output of the image is control by the imagesetter (the machine that makes the negatives) and not by Illustrator , CorelDraw, Freehand, Xara Xtreme, etc. With native Adobe Illustrator artwork (meaning no image placing) you do not have to worry about LPI, DPI (Dots Per Inch) or resolution.

    Be aware that when you print the artwork, you will able to see the dots instead of a smooth screen. Specially if the files was output with a low LPI.

    See attached JPEG file to compare printed half tones with computer half tones (Output was 133 LPI)

    Sometimes is better to go with solid Pantone colors when you are printing t-shirts. But this type of questions you can have a better respond is your post at Design Forums - Print Design: http://forums.adobe.com/community/design_development/printdesign

    I hope this answer your question.

    7 replies

    Participant
    April 18, 2013

    I believe the KEY element to all of this is to FIND A PRINTER WHO IS NOT a money grubbing, "I'm going to make this PMS or whatnot into FIVE DIFFERENT colours instead of ONE using varying gradients..." I've found a wonderful printer who actually despite me working as a graphic designer in a medium sized print shop...schooled me WELL into DOT GAIN, etc inter alia...so, finding a printer who is willing to actually share with you is PARAMOUNT to foregoing all the BS that can occur if you happen to get printer who is a total wanker. Init? Aight. I'm out.

    Participant
    April 19, 2013

    I don't think that printers are necessarily "money Grubbing" particularly. I would suggest probably, if anything they’ve become LAZY and DUMB. I strongly believe that since this topic was first raised in April 2009 (4 years ago) the whole printing and pre-press industry has been so dumbed down to the point where a true "craftsman" now days is hard to find. We’re all being forced to go with 'standard'. Many have surrendered to the whole 'push-button-buy-off-the-shelf/McDonalds' kind of mentality — there’s no skill any more.

    To a large extent the demands made by the average customer have driven this phenomenon and a big part of that revolves around cost. Probably because so much of what we consume today is produced in China, much of which is utter CRAP I might add. So that's what the market has come to expect. People want everything yesterday and don’t want to give anything any real serious thought.... until suddenly there’s a problem.

    I have a customer who complained that there was something wrong with their logo which I designed for them and supplied as a.jpg (that's what they wanted at the time — probably so they could use it in a Word document and print it off on their office inkjet). Problem was it printed out a different colour with every different printer they took it to – from business cards to large scale signage, etc, etc. all on different substrates using different inks. Of course they didn’t tell me that’s what they were going to do, but they rang me months later to complain about the problems they were having with their logo. None of the printers wanted to take responsibility or could explain what the problem was. Of course, it was all the designer's fault (me) because that’s what the printer told them. What a LAZY, DUMB answer! Just covering their butts no doubt. I explained how the problem was related to how each different print device is calibrated slightly differently, resulting in the variations in colour she was seeing. She didn't want to know about all that. In her opinion the whole printing industry should have more fool-proof systems that guarantee more consistent results. I advised her to make sure she always took a colour sample for them to match to, so they can adjust their equipment accordingly.

    I find it inconceivable that a printer’s first response is that there’s something wrong with the artwork — they all worked from the same piece of artwork but with all different results! Printers aren’t skilled craftsmen like they used to be. They’re just copy machine operators with no real understanding. (This doesn’t apply to any SKILLED craftsmen reading this)

    Sorry if I was ranting...

    Participant
    April 19, 2013

    Hi! Dave, I was NOT at all lumping all printers together, just like

    everything in life you get good and bad...honest and dishonest..and I

    believe some (the one I've worked for for over 20 now, I KNOW for a fact

    increases cost by about 700 percent write up....even with me, my wedding

    invitations which I designed he screwed me LOLOL...anyway you're totally

    right...and I thank you for your honesty, insight and good nature.

    PEACE BRO

    Randall

    RogerPaine
    Participating Frequently
    August 12, 2009

    What a huge topic!

    I have used Illustrator to output seps for screenprinting t-shirts since V.7 and never had a problem. I do full colour cmyk prints and spot colour/halftone prints. I set the screen angles, frequency and dot shape in the print dialogue. If you're printing through a 120t mesh use a 52 line screen for the black - or lower frequency for lower mesh count. I think the rule is one and a half threads per dot.

    As I say, I've done it for years, both for hand printing and auto and won many awards for it. Never had anything we couldn't sort in illustrator.

    Your laser printer might be the issue.

    One other thing: you are going to loose the tone in the top 10-20% of your half tone and get dot gain in the bottom 10-20%. There is not a lot you can do about that other than push the levels in your art to allow for it. The amount of dot you gain/loose depends on squeegee sharpness and durometer, mesh count, emulsion thickness, machine pressure, fabric quality and if its printed on a friday arvo or monday morning - neither of the latter are good.

    OsakaWebbie
    Inspiring
    August 12, 2009
    What a huge topic!

    Yes, this has been a good discussion, both before I leaped in and after.  I love learning!

    Perhaps if I talk to the right person at the replication shop (whoever actually does the setup for printing the silkscreen disk labels) I might discover that he has a printer driver (and therefore a print dialogue) that has all the needed options to do the screen the way that works best for his equipment - if so, then I'm happy to leave it alone and let him do his thing.  But since the physical replication of the DVDs isn't even done in Japan (the factory is in Taiwan, I think, because overhead is cheaper), the printing may be done there as well, so I might never meet the actual silkscreen guy.

    My lack of Postscript printer isn't really related because I won't be printing anything myself - all I have to do is give the replicator my Illustrator file, as long as my text is outlined and my graphics not linked.  I was surprised that they don't even care if the objects in the different colors are separated by layer or not - I sort of assumed they would want me to give them a file with all the white on one layer, all the purple on another, and all the yellow on another, but the guy who talked to me said it doesn't matter to them (of course that was also the guy who wasn't sure if they could do halftone or not).  I'm getting more and more curious to ask them again, but this week is the second biggest holiday time of the year in Japan, so they are probably closed for a few days.

    One other thing: you are going to loose the tone in the top 10-20% of your half tone and get dot gain in the bottom 10-20%. There is not a lot you can do about that other than push the levels in your art to allow for it. The amount of dot you gain/loose depends on squeegee sharpness and durometer, mesh count, emulsion thickness, machine pressure, fabric quality and if its printed on a friday arvo or monday morning - neither of the latter are good.

    If I understand you correctly, you're saying that if the opacity setting for an area of color is low but not zero (10-20%), or high but not 100% (80-90%) then the size of the dots or holes ends up too small for the screen to do smoothly, right?  That makes a lot of sense.  Thanks for the advice - I'll avoid those levels, and I'm sure that others who read this thread will appreciate the tip as well.

    Participating Frequently
    August 12, 2009

    We use InDesign to create our films.  We simply place your Illustrator file in an InDesign template, add crop marks and color names and send the file to our rip.  We have a standard set of instructions for our halftones.  Our dots are elliptical and each color is set to a certain angle so they don't interfere with one another.  After we have films we create the screens from those.

    Our films are created at 100 lpi for solids and some spot color halftones and 133lpi for full color prints and some intricate spot color halftones.  I believe everything gets shot on screens using a 385 mesh.  We get great results and for this type of printing I wouldn't go any lower. 

    As far as setting up the art.  I wouldn't go any lower than 20%.  Our halftones get very spotty around 15% and lower.  If you're printing on the silver of the disc keep in mind this is fairly distracting so I would make the halftone even darker.  A silver disc with a 25% purple halftone will just look silver with a purple hue.  Also keep in mind that any time you have a screen printed halftone you will be able to see the little dots that make up that halftone.

    You also mentioned a custom white.  I would make very clear to your replicator which parts of the disc you want white.  I usually have artists assign a special color to the areas that need to print white and name that color "custom white ink" or something like that.  I also would name a background color "silver of the disc" just so there cannot be any confusion.  I'm pretty good at deciphering what people want but it's always nice to have extra instructions.

    I hope this helps.  If you have any questions or would like me to look over your art please feel free to send it over.  I can't imagine a prepress department in Japan or Taiwan can be that much different than mine, right?  Maybe?  I also have our printing specs available in a pdf format if you would like those.

    - an

    Participant
    June 8, 2009

    Hello People,
    Firstly accept my appolagies... my english is not great, im a creative person lets ust leave it there ;-)
    OK Gradient or Halftones in AI for screen printing:
    i have been a graphic designer for many years and have had exposure to all sort of applications and i figured there must be some way and there is! i be gan my pusuit after blindly investing in screen printing equipment and jacking in my job.

    LETS START:

    * create a few squares in illustrator.
    * fill each of them Reg black ( the circle and cross hair in your swatches)
    * select each one in turn and change the "tint" colour of each one say 100%, 75%, 40 % and 20%. you will be able to see the difference on screen.. as roughly the desired effect.
    *now in the filter tab select (pixellate - colour half tone) the channels for this experiment can all be set to "0" appart from the bottom one. as this is "K" from the CMYK Pallet (black) and all it does is arrange the angle of the dots - 45 is good. by setting the number in the top option you can change the size of the dots. smaller number small dots.
    * click ok or apply and your design will be applied and turned dots
    if you want to take this one step further...???Scale the design up (be patient) go to the "object" menu - click "rasterrize" keep the quality high, like 300dpi.
    * then i know this is a little arse about face but bare with me...
    * now the object is no longer a vector your live trace option should be available (if not chnage your work space to basic and it should appear)
    * from the drop down select custom. now the fun begins and you will learn waht works best for you but. 1) ignor white 2) set all options on the right to "2" for corner angles etc .. etc.. 3) just play with the threshold slide bar and you will see the changes on screen if you have preview applied?
    finally
    * click expand.. now you have a fully fledged vector again.. in dots.. and scaleable...
    i know it takes a bit of getting used to but it worked for me! on a very basic 55t screen i managed to simulate 5 shades of blue WHAT A CHEAP SKATE lol... printed really well!
    i get so much help from these forums... i hope this helps someone else.
    Happy Dotting

    OsakaWebbie
    Inspiring
    August 8, 2009

    I'm trying to use Illustrator CS2 to make a silkscreen label for a DVD.  The replicator company making the DVDs didn't have specific instructions for halftone resolutions (I don't think they had dealt with them before), so I decided I better make the dots myself rather than handing them a file with various transparency settings and hope they know what to do.  Other DVD/CD labels I found that had done halftones seemed to use 42 lpi, so something like that is my target.  I will just be giving them the Illustrator file, not printed masters for the screens, and my printer isn't postscript anyway, so all the PPD discussion don't help me.  But I read CaptureStudio's post with interest - it sounded very promising.

    But... it didn't work for me.  First of all, the Pixelate filters are only available after I rasterize.  Okay, so I rasterized my 25% opacity registration-black box (selecting grayscale as the method), and then selected Pixelate->Color-Halftone.  I left the top selection at the default 8 pixels (I think my document resolution is 350dpi, so that's just about right), changed the first three channels to zero (the fourth one was already 45 by default), and selected Transparent for the background.  I was surprised that the first three channels were even there, because in grayscale the C, M, and Y should not exist.  Anyway, I did that, and then zoomed in to see what it did.  But unfortunately the result was not black dots, but a strange gray texture pattern - nothing was black, white, or clear.  CaptureStudio, what version of Illustrator are you using?  Perhaps that is the difference.  Or perhaps I did something else wrong.

    I have Photoshop and the replicator will accept that, so I could move the file over there.  But unless there is a trick I don't know about, when I open an AI file in Photoshop just makes everything (all its layers, text, vector objects, etc.) all one raster glob, and seems to also add smoothing to the edges of my vector shapes - not best for trying to end up with clean spot-color data.  So if possible, I want to do what CaptureStudio suggested and stay in Illustrator, so that I have clean vector data for everything including the halftone dots.

    May 21, 2009

    In the print dialog, set your printer, confirm your PPD, page and all of that.

    Change your print mode to separations, confirm your other settings...  The lower part of this dialog shows a list of spot and process colors, double clicking on any of these offers full customization. You can set it to whatever your printer will allow given the image setter's setting are set to receive them. As a general rule, it defaults to 60 , but 55lpi runs good on most 200-230-305 mesh screens , I drop it to 45 for 156mesh and 35 for 110's and lower.

    JETalmage
    Inspiring
    April 10, 2009
    So you can't control half tone dots in Illustrator.

    Print dialog>Output pane. Set Mode to Separations (Host based). You can set the halftone ruling, angle, and dot shape for each separation plate.

    JET

    April 10, 2009

    It's been my experience that when I assign those settings in Illustrator, it's up to the output device on whether to deliver or not.  I haven't been able to get my printer/RIP to give me a halftone dot, just a typical stochastic print.  This has been the case since I started using a software RIP, which in my case, is limited unless I go to Photoshop and print a 1-bit Black and White halftone dot there.

    Skullmaker
    Inspiring
    April 9, 2009

    Hello Everybody,

    If you going to output from a laser printer, there are lot of factors at play.

    I have at home a 1200 DPI printer that comes with PPD driver that allows me to choose LPI (Now my printer is 5 or 6 years old, and I am using Ai CS3). You have to ask your self how old is the laser printer and the computer that the screen printer is using with a software that is from 1987. This can creates problems if the laser printer is not 100% compatible with the newest driver version.

    Then again, Illustrator does not have control of my LPI, is my printer and the PPD installed that actually determine the output of the artwork (see attached JPEG)

    Old versions of Illustrator and CorelDraw had this feature because the printer did not have any PPD software. Today, you have to see how much memory the Printer have, what level of Postscript, does it have the new USB3, etc.

    A 300-600 DPI laser printer can usually only print at an LPI of 50-65. Everything depends on what printer do you have.

    So do you know how old is the computer and printer?

    Mojorocker1964
    Participant
    April 10, 2009

          I notice that your PPD offers many more options. So each printer's PPD file offers different settings per printer manufacture. Thats good to know. What I was driving at was, in the old CorelDraw! 7 software, you could set the dot frequencies and or line frequencies in the actual software. Just as was stated, probability because the printers of that era did not have the capability. As I type this, my mind is forming an action script to accomplish the same goal. It would be a great little feature or plug-in if I can get it to work. Unless someone knows of something similar.

         I'm usually just designing and not actually outputing the films. When I heard that my designs were being sent through 22 year old software in order to get the halftone dots right, I was to say the least puzzled. Had I known that He was having to do that I would have investigated this long ago. I thank everyone for the help. When I figure this one out I will be sure to share.

    OsakaWebbie
    Inspiring
    August 8, 2009

    Picture 2.png

    Rather than make use the transform filter you might want to look into filling the objects with a pattern swatch. Or make your own pattern swatch to give you the course screen you need. This would be object specific.


    I've never made my own pattern - it sounds like a lot of work, but I could try.  But is it even possible to have a pattern that is part opaque (and whose color can be defined by a swatch) and part transparent?  The halftone screen I'm trying to create would have dots of color with no color between them (the silver of the DVD would show through).

    Skullmaker
    SkullmakerCorrect answer
    Inspiring
    April 9, 2009

    Hello Mojorocker1964,

    Adobe Illustrator gives the freedom to output the artwork at any LPI or DPI you wish (The Typical LPI for offset printing ranges from 85-133 lines per inch)

    The output of the image is control by the imagesetter (the machine that makes the negatives) and not by Illustrator , CorelDraw, Freehand, Xara Xtreme, etc. With native Adobe Illustrator artwork (meaning no image placing) you do not have to worry about LPI, DPI (Dots Per Inch) or resolution.

    Be aware that when you print the artwork, you will able to see the dots instead of a smooth screen. Specially if the files was output with a low LPI.

    See attached JPEG file to compare printed half tones with computer half tones (Output was 133 LPI)

    Sometimes is better to go with solid Pantone colors when you are printing t-shirts. But this type of questions you can have a better respond is your post at Design Forums - Print Design: http://forums.adobe.com/community/design_development/printdesign

    I hope this answer your question.

    Mojorocker1964
    Participant
    April 9, 2009

         So you can't control half tone dots in Illustrator. I'm aware that the printer profile controls some aspects of the dots. The shop I do work for on occasion asked me to save a file for CorelDraw! 7 because Illustrator does not offer a convient way to control dot size and feq. I was amazed to find that He was correct. This was after I traveled 15 mile to his shop to load a PPD file and sat with him over my sholder for over an hour only to find that you can't control the dots with Illustrator. He then sat down and opened the file with CorelDraw! 7 ajusted the dot size and printed it out just fine. This from a software package that came out in 1987. I was schooled by a silkscreener using software that is 22 years old.

    April 9, 2009

    This has been a frustration I have with Adobe who created Postscript Level 3.  I remember using Illustrator 6 to output separations to my Postscript Level 2 inkjet ( 600dpi ) which results in 56 lpi screens that were inadequate at best because of the low printer resolution.  Screens are usually created in the RIP and, in the case of Illus 6, the RIP was built into the printer as a hardware RIP.  Very convenient.  I was able to print seps out of Quark, too.

    Now, I believe you need some kind of third party solution like Acrobat Pro or Photoshop.  Keep in mind, the silkscreen mesh determines what halftone frequency to use.  A 35 lpi screen is not unheard of.  I find Photoshop a little more flexible in that you can assign whatever frequency you want and assign the screen's dot shape and angle and, then, print 1-bit line art seps.  Otherwise, you're going to need a fairly expensive RIP application that can output dot-by-dot separations on your output device.  This, as far as I know, cannot be done in today's Illustrator.  Illustrator can print separations, but not dot shapes.