Illustration on black illustration board
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When I went to my first SGIA Show in 1977, there were two topics of discussion during the Textile Division meeting. One was Four Color Process and the other was Multicolor Printing on Black shirts. Today, those same two topics still draw a crowd. There are many differences between what we can do today and what we had to do back then, back before the flash had been invented and automatic presses could only do one print stroke and had very few other options. Sometimes I think that because we had fewer options we had greater success, but I know that isn’t true. There were printers then that could do a good job no matter what they had and others that couldn’t, no matter what they had.
The first thing to look at is the artwork. Bad artwork will never be anything more than bad artwork, no matter how well it is separated and printed. Let’s take a quick look at the design elements that make artwork for black shirts different than artwork for light colored prints.
In order for a design to work well on a black shirt, the black of the shirt has to be an integral part of the design. You never print black on a black shirt. Start bydesigning your artwork on a black background, not white, and make it big. Those that want to wear a black shirt want to be seen. When you design on a white background, you put in the highlights, mid-tones and shadows. When you design on a black background, you put in the highlights and mid-tones, the shadows are already there from the black of the shirt. In order for your design to jump, it requires contrast. You can get the contrast by giving your design lighting from one direction-any direction except straight in front which flattens out a design. The single point of light will create strong highlights and allow for strong shadows-black.
Don’t be concerned with being anatomically correct, this isn’t an anatomical drawing, it’s a design that has to be printed on a garment and look good there. Opposite the strong highlights, add some additional soft light so the design doesn’t fall away, even if this light doesn’t seem correct. Nobody will know or care. Use lots of strong colors. No one wears a black shirt to be subtle.
By the way, there are quite a lot of separation programs available. Just remember that bad artwork separated well is still bad artwork.
Screens should be at a tension level that will allow the ink to go through the mesh and sit on the shirt, not on the pallet. If your pallets have ink on them when you’re done printing, you either had low tension or used too much pressure. I like to use 35 N/cm for all of my screens for printing on black shirts. I use a 156 mesh with 64 micron thread for my underlay on t-shirts and 230 mesh with a 48 micron thread on top of the underlay. For fleece, I use 110 mesh with an 80 micron thread. My halftone dots are 45 LPI, 61 degree angles and always elliptical for all of my colors. This gives me the ability to lay down a decent amount of ink and avoid having moiré problems. I could go to a higher LPI, but that would only increase the degree of difficulty and if my client isn’t willing to pay more, why do it. Going to 55 LPI will give you a little more detail, but it won’t be noticed from three feet away. If you’re going to enter shirts in one of the industry contests, then going to a 65 lpi will probably be necessary or the judges will probably not consider your print for an award. These are competitions based on technical merit and less than a 65 LPI probably won’t be a contender. Should you increase your LPI, the dot shape and angle doesn’t change, but the mesh count may increase. The formula I use to determine my mesh count is as follows: LPI x 4.5=? increase to the next mesh count up. For example, 65 LPI x 4.5 = 292.5, next mesh up is 305. The important thing is using a number that is odd as your multiplier, 4.5 being an odd multiplier. As your LPI goes up, so should your multiplier, but always odd. As you go down in your LPI, the multiplier should not go down of you’ll create a fabric interference moire'.
Squeegees are one of the most over looked items in a print shop and yet they have so much to do with the quality and speed of production. If you own an automatic press then you should own a variety of squeegees and a squeegee sharpener. A small shop with limited automatic production of 2,000 prints per day rubs a squeegee over the stencil 10,000 time per week if they didn’t change the squeegee. Do you think that the edge of the blade didn’t wear? Sharpen your squeegees every one to two week. Sharpen new squeegee to make sure they are straight in the squeegee holders or you’ll be printing with excessive pressure and putting the ink through the garment, even if you have high tension.
For printing on black shirts, I like to use a 65/90/65 triple durometer squeegee for all of my colors. The triple durometer allows me to put pressure on the edge of the blade without letting the squeegee curl. This way I am not printing with the side of my squeegee. For my white underlay, I want a vibrant white on one stroke and a speed that will allow me to get product out of the door. I use an angle of 20-30 degrees which will give me the vibrant color and sharp dots. I use a medium speed. With an MHM press, that would be between 5-7 and a pressure of about 40 pounds. The white ink usually dictates the speed of production so the faster it prints, the more you will produce. The purpose of the white underlay is to seal the shirt off from the colors that will be printed on top of it. The underlay doesn’t have to be very vibrant to be effective. I like my squeegees to start above the design and finish about two inches past the design so the mesh has time to peel away from the ink. Set your off contact so the outside of the screen up a little and the mesh is peeling from the print until there is no sound when the print is done and screens lift.
The other colors may vary in their squeegee angle based on the amount of ink needed to make the print look good. Darker colors are usually more opaque than lighter ones and would not need as much angle. Often the color order is dictated by the software used to do the separations. If you’re able to choose the color order, print the dark color early and the lighter ones towards the end
If your client requires you to design so the print can be put on any color garment, then design for black and add the black when printing on colored garment. I like to print black first, then white, flash and then all the other colors. If you design for a light colored garment and need to print on black or dark colors, you’ll need a solid underlay and that always flattens the image and usually requires more flashing. On white garments, it is not necessary to print the white underlay and the design should be able to get printed without using a flash at all, just the way we did it many years ago, except we did it on all colors that. Keep in mind that prior to about 1981 the flash had not been invented and we were printing up to eight colors on black shirts.
Necessity is the mother of invention.
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