2 Replies Latest reply on Dec 22, 2009 7:52 AM by Wade_Zimmerman

    How to print artwork by each individual color for screenprinting?


      I am trying to print each individual color of an artwork created in illustrator to make the screens needed for screenprinting on t-shirts.  Can anyone please tell me how to print the individual colors used in a design?  Do I need to use the print feature to separate each color into it's own individual pdf file then print the color separation from those newly created pdf files?  If attachments are needed, please let me know.




        • 1. Re: How to print artwork by each individual color for screenprinting?
          JETalmage Level 6
          Can anyone please tell me how to print the individual colors used in a design?

          Not without seeing the design.




          You are asking for someone in a user-to-user forum to give you a crash course on color separation for printing. This isn't the best way to learn that. You need to get some books, take a class, or maybe work in a print shop for a while.


          Here's the general gist:


          Printing (whether screen printing or other) does not print the 16-some-odd-million colors that your glowing monitor displays. Printing just lays down a small handful of colored inks. It fakes all other colors by some "screening" method by which little dots of a few primary colors are laid down in the same regions. ("Screening" in this context is not referring to the screen printing method here, which, just for clarity, I will hereafter refer to as silkscreen printing.) The human eye then effectively "mixes" those primary colors to see other colors.


          That, in a nutshell, is what is meant by process color printing--using screens (arrays, grids, or random distributions) of tiny dots of 1 to 6 "primary" colors to simulate many more colors than are actually there.


          Process color separation ("separating" the kazillion colors you see on your monitor into the small handful of "primary" colors)  is handled by the software. You can use any colors you want in the design, then choose Separations in the Output tab of the Print dialog. The resulting output will be grayscale values that will in turn be interpreted as different-sized or differently-spaced tiny dots in a 1-bit (only black; no grays) printed sheet (paper or film, or nowadays emulsion directly applied to a press's plate). Those printed sheets, containing only dots of "image on" (again, no grays, just solid black dots), are the patterns that actually get duplicated with ink.


          But here is where you get into the mechanical problems/limitations inherent in the silkscreen printing method. Silkscreen method actually squishes ink through a fabric screen onto the substrate (in your case, the T-shirt). The image has to reside on the screen fabric in the form of an emulsion mask. As you can imagine, there is a practical limit to the size of details that method can handle. The dot sizes typically used in commercial offset printing (the method assumed by programs like Illustrator) would effectively "fall right through" the openings of the screen fabrics typically used in silkscreen printing. This is further exacerbated by the absorbancy and roughness of the substrate (the T-shirt fabric).


          So while silkscreen printing can and nowadays often does support process color screening, it generally (espcecially in T-shirt printing) requires much larger dots (typically 50 lines-per-inch or less) than the default sizes that you are going to see in your software printing options. Someone has to set this dot size. This is where you get into the expertise limitations of individual silkscreen shops--which varies all over the place--which brings me to this caution:


          Using FreeHand, for many years I reliably did this:


          1. Create the design in FreeHand.

          2. Export to color-separated PDF, specifying a couse halftone screen ruling suitable for a T-shirt silkscreen shop.

          3. The resulting PDF would contain grayscale pages, one for each ink to be printed.

          4. When the printing shop (many of which have no understanding of halftoning, even though they attempt to use it) opened the PDF in Reader, and printed it to a PostScript printer, the output halftone dot size setting (called the halftone ruling) was as I specified. (The halftone ruling was embedded in the PDF, and survived the trip.)


          I was never able to get that to occur reliably with Illustrator. The halftone ruling either did not get embedded in the PDF, or was over-ridden by the defaults of the output device. So I mention this as a caution: IF you are going to try to use process color in your designs destined for T-shirt printing, you need to be very aware of the importance of dot sizes and angles, and you really need to work with a silkscreen shop that truly understands process separation and handles it correctly. Trust me, not all do.


          Now...Because of the course size of halftone dots required by silkscreen method, its results can be quite unsatisfactory, for these reasons:

          • If using process CMYK inks--which are not opaque--it doesn't work on dark substrates, unless the printer first puts down a solid opaque white and then prints the process inks on top of that. That results in another problem: The total ink buildup is so thick that it doesn't "breath" and the shirt feels horrible.
          • The result is often just plain ugly. Unless done by one of the relatively few technically sophisticated silkscreen shops, the halftoning is fuzzy, blotchy, posterized, plugged. Color is groosly inconsistent.


          All the above is why, when possible, process color is best avoided altogether in T-shirt silkscreen printing. It's why silkscreen printing is heavily dependent upon spot-color separation. Even designs requiring process color are very often augmented by solid spot colors in order to impart a sharpness and "snap" that would otherwise be missing.


          So unless you are preparing the design for reproduction by a truly sophisticated silkscreen shop that is able and willing to coach you, you would be better off sticking strictly to solid spot color design. That is, avoid for now not only process color, but also tints of your spot colors. Ease into the use of process color as you gain experience and understanding.


          Using spot colors involves responsibility from the start on the part of the designer. It's not difficult, but you do have to set the file up correctly, and you do have to understand the basic considerations of the silkscreen method.


          • Think in terms of INKs, not colors.
          • Know how many total INKs are going to be printed.
          • Create ONE Swatch for each of those INKs and define it as Spot Color. It is best to use colors that are reasonable facimiles of actual silkscreen INKs; otherwise the silkscreen shop will have to try to mix the colors you are using. It is best to name your spot colors according to the names of the actual silkscreen INKs. Somehow, you have to communicate unambiguously to the print shop what colors you want. "Beautiful bermudan blue" means nothing to anyone but you.
          • Use only those Swatches in your design. Don't use other colors just mixed willy-nilly from the Color palette. If you do, those will result in up to four additional separations when you print seps.
          • Don't use any Illustrator features that result in raster images, and that don't respect Spot Color. If you do, those objects will be automatically converted to process color, and you'll again have too many separations.
          • If different-colored elements overlap or touch, understand overprinting and trapping, and use it judiciously.


          If you've done that, then you can "print" the design to a PDF, using Adobe PDF as the "printer." That will present to you the standard Print Dialog in which you can specify Separations on the Output tab. Because you have not used process colors or tints of your spot colors, you won't have to concern yourself with halftone dot shape, size, angles, or rulings. Turn on the options for Registration Marks and Page Information. The resulting PDF should have one page for each INK you used in your design. The images on those pages should all be solid black, not grayscale. Send that PDF to the silkscreen shop. Also send a PDF that is not color-separated, so the printing house can use it as a reference.



          • 2. Re: How to print artwork by each individual color for screenprinting?
            Wade_Zimmerman Level 7

            I did not read the previous response but go to the print feature and print to a postscript and you can choose a separation type then print to ps and then distill that and you will have a separated pdf.


            Now you have to make certain you have spot colors for all the colors or they will separate to process which is not what you want.