I was told that we couldnt Screen print a 4 color process on black shirts. I am not a screen printer but i do artwork for a local screen printer and he is the conventional 1 or 2 color job kinda guy but he recently bought an Epson printer with Accurip software which produces the separations for us. The only thing is Accurip doesnt separate a white base layer, or does it? My guess is that we lay down a white base/ flash it. lay down the yellow/ flash it. followed by the magenta cyan and black in the same way?
Accurip is a RIP program, not a seperations program. All it does is act as a RIP processor to allow postscript halftones to be printed out on non-postscript printers.
Printing 4 color process on black shirts is not impossible but it is difficult and a printer who does not have much experiance with 4 color process will have a hard time making it look right.
The reason is two fold. Process inks are simi-transparent and are formulated to be printed wet on wet. This forumlation is also designed to give the optimum gambit on light colored shirts. Remember, shirts are not hard surfaces and do not print like most signage substrates. You have absorbtion and dot gain to deal with. This is what the inks are made to help deal with.
When you print on a underbase the game changes. The underbase must be layed down and then flashed. This flashing process simi-cures the underbase ink. Once the underbase has been flashed it is no longer absorbent like the shirt material is normaly. This changes the way the 4 color process inks work and will result in colors being extremly week or extremely strong depending on the art.
The printer must know how to dial down the ink intensity during seperation to help compensate for this. They must also know how to adjust the printing process as needed during the print run as the screens will start to load on the back and thus change the way the final print looks.
There are seperation programs out there that will allow a novice process printer to have a good deal of sucess printing 4 color process and even a good shot at doing so on darks. I would mention the one I think is best but I am not sure the forum rules allow me to do that. And no I do not sell it. The other option would be to send the artwork to a artist that is skilled in creating seperations needed to do this.
The best solution for someone who has very little 4 color process experiance would be to use simulated process or index printing when printing that type of art on to shirt.
