Comments on: Butt or Trap? Spot colours.

By: Steve

Steve — Wed, 17 Jun 2009 07:11:08 +0000

Hi Esta

We generally print light to dark, there can be some variations on this. T shirt Printers always use two whites when printing plastisol inks on to darker shirts, a base white which goes under all lighter colours which might be altered by the underlying shirts colour, then a highlight white which is applied later or last in the sequence. In the example you mention the fine white lines could be applied on top of the darker colour, leaving it as a solid block. It is also possible to print the dark colour over a solid white leaving the lines to show through. It very much depends on the inks your printer is using and his machine/carousel set up. These variables have been dealt with in different ways by different printers, this is the reason many screen printers prefer to take care of more complex separations in house.
If you wanted to print using discharge inks, only one white is applied, there would be no layering of ink, so butt registration is required, and a very accurate press…I think an article on colour sequences is required, thanks for your comment, I hope this helps a little.

By: Esta

Esta — Tue, 16 Jun 2009 08:52:44 +0000

Thanks for this article, It gave me some more insight in the printing process. As a designer for tees I’m trying to get a better understanding of these things so we can deliver the artwork in aprinter friendlier state.

A related question: Is there an optimum stacking order of colours?
For example: would you always print the lightest colour first and end with the darkest colour? Or the other way around? Or does it depend on the artwork?
We sometimes have photoshop designs where thin white linework overlaps bigger solid dark shapes, destined for, say, an orange tee.
I wonder how a printer would prefer to handle that?

By: Steve

Steve — Fri, 12 Jun 2009 17:43:27 +0000

Thanks for your comments Lawrence, artwork is key to a good print, I agree, the overlapping of translucent inks is a great technique for achieving more colours with less screens. Although screen and litho printing are worlds apart in some respects there are many principles shared by both that will never change, and although the computer age has transformed both industries quite dramatically, a bit of old school, hands on, know how never goes amiss.

By: Lawrence Cremore

Lawrence Cremore — Fri, 12 Jun 2009 14:13:59 +0000

Hi, Yes I found your site interesting, Registration is always a Key factor, in all Printing, more so, for 2 plus multi colours and of course waiting for one to dry before you can apply the next, then shrinkage could occur. ?
also overlapping colours is great if you use a colour to blot the other out (as Black), but if you use a lighter colour, you end up from using 2 colours-you get 3 colours as from the overlap.
So to do a but up to a colour? must be hard? especially in, butt up same colour to the left and right of the 1st image colour, On a long run, with Humidity, that affects your stock.
At 58 years old, I used to be (redundant now, due to this Digital age) an Offset litho Print Machine Minder, on a SRA2 Kord, and printing reversed writing out of printing 4 colour half tones in opposing corners of the sheet guides, can and did cause real problems.
So you have “Trap Registration”, would that be an image of your work shone down as a still image, to place the next colour to print?
I am just interested, as your work seems interesting, as I give thoughts back to my old job.
Then I was always in my job, to turn out work only that I would like done for me, in that way I felt I was giving my best.

Hope you have not thought, what a nutter emailing in, it’s just pure interest from me.

All the best,

Lawrence.