Need help with trapping - newbie here :D

[AlexRossi76]

1234567890

 

[zoran]

Usually printers like to trap their own files, especially in packaging.
I would suggest you look at better service elsewhere as these days it is/should be all about service you receive from your print provider.
That being said, this is trapping they are asking you to do.
If your white text is laid on top of rich black background, in case of slight misregistration on press that will happen, trust me, one or more colours will show up in white text area and caused text to "plug up" and/or become ineligible if small enough.

To prevent this from happening, you need to stroke text with darkest colour, usually black.
What this is going to do is in case of misregistration, other colours will move slightly under the black but will not show in white and your white text will stay white.

On our rips, we have automatic setting that does this and "pulls" back other colours under the white during trapping function.

I hope this helps.

 

[AlexRossi76]

1234567890

 

[AlexRossi76]

Usually printers like to trap their own files, especially in packaging.
I would suggest you look at better service elsewhere as these days it is/should be all about service you receive from your print provider.
That being said, this is trapping they are asking you to do.
If your white text is laid on top of rich black background, in case of slight misregistration on press that will happen, trust me, one or more colours will show up in white text area and caused text to "plug up" and/or become ineligible if small enough.

To prevent this from happening, you need to stroke text with darkest colour, usually black.
What this is going to do is in case of misregistration, other colours will move slightly under the black but will not show in white and your white text will stay white.

On our rips, we have automatic setting that does this and "pulls" back other colours under the white during trapping function.

I hope this helps.

Hi Zoran,

Thanks for your reply and insight, it makes sense.

If I do stroke the text with the darkest colour which is black, would the stroke have to be set to overprint?

 

[zoran]

You would need to knock it out, otherwise if it's set to overprint, it will let other colours underneath.
It's hard to explain without showing you in real world, but imagine there has to be white, than black only stroke, than rest of the colours with black.

 

[AlexRossi76]

1234567890

 

[AlexRossi76]

You would need to knock it out, otherwise if it's set to overprint, it will let other colours underneath.
It's hard to explain without showing you in real world, but imagine there has to be white, than black only stroke, than rest of the colours with black.

Could I just ask quickly though. If the black was set to a spot colour black, there would be no reason to trap the text right?

 

[gordo]

Could I just ask quickly though. If the black was set to a spot colour black, there would be no reason to trap the text right?

This is what your printer is asking for (See attached "Keepaway.jpg")

On the left is the Black plate and on the right, with half of the black plate cut away are the CMY plates. Note that the letter in the CMY plates is "fatter" that the letter in the black plate. This is called a "Keep away"
So when the CMY plates go out of register the inside edge of the type is still white. (See attached "KeepawayMis.jpg")

Whenever you have type or line art reversing out of a multi-color area you will need such a keep away trap. In your case you cannot just stroke the text. You need to make the CMY text fatter (stroked) than the black only text. It does not matter whether the black is a pms or not. It only matters if it is a multi-color background.

gordo

 

[AlexRossi76]

1234567890

 

[gordo]

Hi Gordo,

Thanks for your reply and images you supplied.
So would I have to stroke the white text with a CMY breakdown only to knock out only in order for this to work?

File attached for reference as a ZIP with .ai file and PDF attached

if I've done this wrong, is there any chance you could set it up on the illustrator file correctly so i can see how it needs to be set up?

Wrong. Also it distorts the letter shapes.
Attached is how to do it. There are two layers. A K only set to overprint and below it a CMY layer. The type in the CMY layer has a white stroke. The white type in the top K only layer can be left as text rather than outlined should you need to do any edits.
The stroke width is too large - it's just to show you the effect.
The CMY percentages are correct (unless your printer requires something else percentage-wise).

best, gordo

 

[AlexRossi76]

1234567890

 

[gordo]

Thanks for that Gordo, that really is a good help!!

Just say tho, for some reason the background colour was a red made up of C=15 M=100 Y=90 K=10 and the text above it was still white.
How would you trap something of a different background colour like a 4 colour process red? I presume what has been sent over wouldn't work?

Well, typically the darkest color (measured as an L* value) is the one that the white text is simply knocked out of. The "fattening" would be applied to the text knocking out of the other colors.
Trapping colors is a non-trivial activity. If you are expected to do it in your supplied art then, IMHO, it's best to have the printer tell you what they want. That way if it fails...it is their fault, you were just following orders.

gordo

 

[rich apollo]

Just say tho, for some reason the background colour was a red made up of C=15 M=100 Y=90 K=10 and the text above it was still white.
How would you trap something of a different background colour like a 4 colour process red? I presume what has been sent over wouldn't work?

Then you can't do a spreadback as the result would be a halo around your letters. You have to start thinking about a design that uses a black stroke around the reverse type, or you just live with the misregister.

This is why keylines were developed around images.

 

[AlexRossi76]

Then you can't do a spreadback as the result would be a halo around your letters. You have to start thinking about a design that uses a black stroke around the reverse type, or you just live with the misregister.

This is why keylines were developed around images.

so if I was to use a black keyline around the text, would a 0.2mm stroke from the outside of the text be sufficient enough to avoid mis-registeration?

 

[Chasfinch]

I am wondering why the printer is asking for that. workflows/RIPs generally see the rich/super black and "choke" or stay away the 3 under colors.

 

[rich apollo]

so if I was to use a black keyline around the text, would a 0.2mm stroke from the outside of the text be sufficient enough to avoid mis-registeration?

That depends on the press, the substrate, the sheet/web size et cetera. You'll have to ask the printer about his process.

 

[pcmodem]

That depends on the press, the substrate, the sheet/web size et cetera. You'll have to ask the printer about his process.

Better yet. Ask the printer if they have the ability to Trap this file. Spin this positively and you will get better results than asking why can't they.