Ask Clive – How Its Made
How many customers know how an idea becomes a reality in the form of a T-shirt? Clive Allcott looks at the work involved.
The artwork or logo is usually supplied by your client and passed to your garment printing supplier. This artwork has to be created in a Vectored or outlined format for solid spot colours, however anything photographic has to be supplied actual size 300dpi high resolution.
Print film positives
Your final digital art file is then colour separated to make film positives. The software communicates this information to an office printer that will print black ink or toner on a clear plastic surface. Some printers can now print directly on to the screen. One film positive is printed for each colour that is going to be screen printed. If the base garment is coloured, then an extra base screen will be created of the full image.
Make the screens
Metal frames are covered with a tight acrylic mesh fabric and coated with a light sensitive emulsion. The dry film positive is fixed to the screen with some clear tape. The frames are then placed on an exposure unit and exposed to intense light. The black ink or toner on the film positive blocks the light from shining on the emulsion in those areas. Once the exposure is complete, each frame is rinsed off with water and the emulsion in the areas that were blocked from the light dissolve allowing ink to pass through the open mesh.
Set up the press
The printer and press operator prints one colour on to a test garment and aligns the other screens that make up the image –this is called registration. The printer then adds the appropriate ink to its corresponding frame and runs a sample by printing all the colours. Adjustments are made until all colours line up.
Each shirt is loaded on to the screen printing pallet and makes its way around the press stopping at each head (or station) where a different ink colour is printed. Once all the colours have been printed, the shirt travels through a dryer to set the ink.
Bear in mind that the same time and set up goes into 50 shirts as 5,000.
You can contact Clive on firstname.lastname@example.org