Misprint Monday: Registration
That green leaf in the photo isn’t arty, it is wrong. It is out of registration. Why are things out of register on your prints? Oh, let me count the possible ways…
- It wasn’t registered properly by the press operator. Start with the obvious, believe me I have seen folks do crazy stuff when all it needed was for the registration to be dialed in.
- Films or files (DTG) that are not in register which may be because of a million reasons that will have to be the subject of another post. A couple quick reasons: with large print areas crappy film or vellum will often shrink. Also run your films all the same direction unless you have a super accurate system.
- Platens are not flat, also warped or tilted platens will affect registration, as will platens that are not all at the same height
- Cold ink is causing the mesh to drag
- Low screen tension or loose mesh or uneven screen tension
- Too much squeegee or flood pressure
- A crappy press that won’t ever hold good registration
- An OK press that is wearing out and needs new parts or adjustment
- An arm on the press that for some reason is not fully engaging into the registration blocks
- Too much off contact
- Too little off contact
- Screens that are too small, particularly on large images
- Crappy spray adhesive or too little spray adhesive. (I was actually in a shop where they were having trouble printing any type of underprint in registration and it was all due to bad spray tack.)
- The artwork was not choked enough or perhaps some nit-wit reduced the size instead of choking the under print (choking and reducing the size are not the same thing…)
- Too coarse of a mesh count
- Ink that is too runny
- Crappy squeegees or the wrong durometer squeegees
- Poor contact between film and screen when exposing the screen (vacuum issues)
- Warped screens
- Too much block-out or tape on the back of the screen
- Overflashing which might mean that you have your flashes on too long, too hot, or too close to the image, or it might mean the substrate is overly sensitive to heat and is shrinking
- Screens are not clamped into your press properly, they are moving for some reason. It can be air pressure related, clamps that are wearing out, or you have the aforementioned crappy press.
- Poorly cleaning the back of your screens after moving the registration
- Over or under exposure of your screens or uneven or inadequate coating with emulsion
- Either your hold-down platen isn’t holding down your garment properly or you are insanely trying to print a lined garment without a hold-down
This is why you want to eliminate as many variables as you can before you have a problem, otherwise you have too much detective work to figure out why you have a problem.