Dan Margulis Applied Color Theory

Black on Dayglo Green

   Date: Thu, 15 Sep 2005 16:22:02 +0300
   From: Toby Macklin
Subject: black on dayglo green

I've put together a book cover that requires two hits of dayglo green (Pantone 802C) as a background. The backcover blurb is black. It seems to me this text might turn out very black indeed, and I wonder if I'd better set it to knockout rather than overprint.

Anyone have experience with this sort of ink?

Thanks

Toby
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   Date: Thu, 15 Sep 2005 14:06:52 -0000
   From: Stephen Marsh
Subject: Re: black on dayglo green

--- Toby Macklin wrote:
I've put together a book cover that requires two hits of dayglo green
(Pantone 802C) as a background.

Two hits to build the required density? The same plate is being used?

The backcover blurb is black. It seems
to me this text might turn out very black indeed, and I wonder if I'd
better set it to knockout rather than overprint.

I would knockout anything that was not fine body text or keylines. You would wish to choke the background under the sharp hole formed by the K knockout. It usually depends on the font design and size. It may only be some text/elements that will benefit from knocking out.

Is this text in Photoshop?

Illus or page layout software?

One pet hate of mine, is that some service providers have their RIP set to automatically overprint all K data.

It came to the point that I would place a white text or box or whatever shape the K object was, under the K object, so that it would force a knockout, despite the RIP, this is with a composite colour workflow (in a pre separated supply of data one then takes full control of knockouts/overprints/traps). Trapping is then needed.  One can get some really crappy results with 'larger' areas of black overprinting solid spot colours, when compared to knocking it out.

Stephen Marsh.
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   Date: Thu, 15 Sep 2005 20:42:23 +0300
   From: Toby Macklin
Subject: Re: Re: black on dayglo green

Hi Stephen and Gary-

On 15 Sep 2005, at 17:06, Stephen Marsh wrote:

Two hits to build the required density? The same plate is being used?

As I understand it, yes, the same plate is being used. Could it be done with two 'duplicate' plates?

Gary suggested knocking out just one of the dayglo plates - I guess this is how that  could be done. Tho I wonder how I'd set that up in InDesign...

 I would knockout anything that was not fine body text or keylines. You
 would wish to choke the background under the sharp hole formed by the
 K knockout.

I don't understand the bit about choking. can you say more?

It usually depends on the font design and size. It may
 only be some text/elements that will benefit from knocking out.

It's mainly 11 point of the regular weight of Minion pro. So I think you recommend having that knock out. Yes?

 Is this text in Photoshop?
 Illus or page layout software?

It's in InDesign.

In the past I have overprinted black text on spot colours. That's the default setting in InDesign. The reason I questioned this now is the dayglo ink and two hits.

Would you recommend knocking out black text against 'ordinary' spot colours (or CMYK mixes)?

Thanks for the help.

Toby
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Date: Thu, 15 Sep 2005 17:41:27 -0400
   From: "Preston Earle"
Subject: Re: black on dayglo green

As always, ask your printer if you can, and I'd generally take their advice. If you can't discuss the issue with the printer, here's my advice:

If the job is being printed in one pass on a multicolor press, the issue you need to be concerned about is wet-ink trap. In order to get a deep, vibrant Day-glo color, the pressman will probably want to run a heavy ink film. With two hits this is less important, but the heavier both films are, the better the Day-glo will look. Because the Day-glo inks are opaque, they need to be printed first in order, before the black. The black will not trap all that well to the heavy film of Day-glo and may look washed out or gray (or maybe even dark olive-green) if over-printed. I'd drop out the black from both green printers. In fact, if this were printed "direct-to-plate", I wouldn't even worry about register-trap between the elements--just a butt fit.

If the job is being printed in multiple passes on a single-color press, wet-ink-trap isn't an issue and you can safely overprint the black and get a denser, glossier look than if you drop out the black.

Preston Earle
www.SawdustForBrains.blogspot.com
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   Date: Thu, 15 Sep 2005 15:38:03 -0700
   From: Jono Moore
Subject: Re: Re: black on dayglo green

On 9/15/05, Toby Macklin wrote:

It's mainly 11 point of the regular weight of Minion pro. So I think
you recommend having that knock out. Yes?

Set to overprint - too fine to trap and you're begging for seeing misregistration if you do a straight knockout. Nothing wrong with black looking black. :)

Remember, printing inks are transparent and black needs all the help it can get, it's pretty weak on its own.

Your printer's prepress folks will probably set it up the way they want it anyway.

Would you recommend knocking out black text against 'ordinary' spot
colours (or CMYK mixes)?

You don't want to knockout black text unless it is fairly large - and even then it will probably look better overprinted, unless it is crossing wildly different colours.
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   Date: Thu, 15 Sep 2005 20:33:48 EDT
   From: Dan Margulis
Subject: Re: black on dayglo green

The responses you have so far indicate that you are caught between a rock and a hard place, because,

a) regardless of whether you are printing CTP, you absolutely, positively, have to trap this type, because a white line between black type and Day-Glo green is going to be disastrous. CTP or no, no printer can guarantee a perfect fit if you just KO the type.

b) but if you trap the type by shrinking the background, unless all the type is very large you might just as well overprint it.

c) but if you overprint it, it may look rather cheesy because of ink transparency issues.

There are two possible solutions that avoid all these problems.

1) Run one of the green backgrounds solid and the other at 50%. Have the black KO the 100% and overprint the 50%. I don't think anybody would see the difference between 100%+100% green and 100%+50%.

2) (Preferred) Run solid 20c0m100y across the page. Overprint this with the black and the two greens, but have the black KO the two green plates. If there is solid yellow and a little cyan behind two hits of Day-Glo green nobody is going to know or care, and it will make further trapping unnecessary.

Dan Margulis
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   Date: Thu, 15 Sep 2005 23:40:24 -0000
   From: Stephen Marsh
Subject: Re: black on dayglo green

As I understand it, yes, the same plate is being used. Could it be done
with two 'duplicate' plates?

What I meant, was that when I was in packaging, printing on metal substrate - sometimes a spread plate was made for the second pass, that had extra hold away in the reversals 'anti-rego' if you like, similar to what one does with cmy or other support tints under a black solid when making rich K seps.

Gary suggested knocking out just one of the dayglo plates - I guess
this is how that  could be done. Tho I wonder how I'd set that up in
InDesign...

It often comes down to separate files when you need to get your hands dirty at prepress time.

It's mainly 11 point of the regular weight of Minion pro. So I think
you recommend having that knock out. Yes?

Hmmm...sounds borderline, I'd check the font and size and see how much room the knockout leaves one trapping is applied, it may be too fine and the final print result would almost be the same as overprinting.

In the past I have overprinted black text on spot colours. That's the
default setting in InDesign. The reason I questioned this now is the
dayglo ink and two hits.

A good default, unless the black text or object is not thin.
 
Would you recommend knocking out black text against 'ordinary' spot
colours (or CMYK mixes)?

Depends on the job and print method.

Each has pros and cons.

Display text yes, not fine body text.

Sometimes display is overprinted, but if the inks are transparent or the density is not high, the show through can be displeasing at times.

Stephen Marsh.
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   Date: Fri, 16 Sep 2005 09:59:51 +0300
   From: Toby Macklin
Subject: Re: black on dayglo green

On 16 Sep 2005, at 03:33, Dan Margulis wrote:

The responses you have so far indicate that you are caught between a
rock and a hard place,

Yes it seems that way to me!

 1) Run one of the green backgrounds solid and the other at 50%. Have the
 black KO the 100% and overprint the 50%. I don't think anybody would
see the difference between 100%+100% green and 100%+50%.

This looks like something I could set up easily enough. Any reason for not having both greens at 100% and have the black knock out just one of them (as I think Gary suggested)?

 2) (Preferred) Run solid 20c0m100y across the page. Overprint this with the
 black and the two greens, but have the black KO the two green plates. If there
 is solid yellow and a little cyan behind two hits of Day-Glo green nobody is
 going to know or care, and it will make further trapping unnecessary.

This would involve five plates, yes? I don't think I can do this as there's already a pantone gray involved as well.

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   Date: Fri, 16 Sep 2005 09:39:25 -0400
   From: Brian Pylant
Subject: RE: Re: black on dayglo green

Remember, printing inks are transparent

Translucent, not transparent. Big difference there.

This looks like something I could set up easily enough. Any reason for
not having both greens at 100% and have the black knock out just one of
them (as I think Gary suggested)?

Dan suggested this to avoid having 100% of the green "contaminate" your black -- when black ink overprints solid spot inks there is the tendency for the black to look muddy or "tinted" with the spot color (as compared to the dense solid black one would want and expect to see, especially from small text) due to the inherent translucency in process inks. Process inks are designed to mix, hence the translucency, but spot inks are not necessarily so, at least not as much.

BRIAN PYLANT
Manager, Electronic Prepress
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   Date: Fri, 16 Sep 2005 15:39:52 -0700
   From: J Walton
Subject: Re: Re: black on dayglo green

I think the concern is that if you only use 50% of the 2nd spot hit you will not get the same intensity.
 Maybe you could do this...
 1st spot @ 100%, with KO for type
2nd spot @ 100%, but a fat 50% where the type is.
Black down last.
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   Date: Fri, 16 Sep 2005 18:39:42 -0400
   From: "Howard Lake"
Subject: RE: Re: black on dayglo green

Process inks are considered transparent. The issue here is trapping of the wet ink onto another wet ink, especially one that involves a double-hit of a semi-opaque color-or any other solid color for that matter. On a multi-color press, there has to be a successive reduction of tack on each ink further down the line. That's why the black doesn't look black. It's mottled. It's not trapping on the wet solid ink, i.e., it's not sitting on top of the other color and looking solid. It's not contaminated by the color ink. How do you contaminate black anyhow? Add some green to black and it still looks black. To increase overall black density, it's common to underlay it with a cyan and maybe a magenta. It still looks black, only denser.

It's a tack issue. The tack on the black, if it's overprinting a solid, has to be less than the first down inks or you have the mottling problem. To complicate the trapping problem, this large solid area should have a reduced tack in order for it to lay down smoothly. But you're talking about laying one solid on top of another solid. So you have a reduced tack ink on top of another reduced tack ink. And, now you want to overprint it with black;and, you want the black to look solid on top of the other inks. Hence, you exacerbate the trapping problem.

Howard Lake
Lake Litho-Printing and Marketing Services
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   Date: Mon, 19 Sep 2005 09:09:53 -0400
   From: Brian Pylant
Subject: RE: Re: black on dayglo green

Process inks are considered transparent.

Again, translucent, not transparent. If they were transparent you wouldn't be able to see them at all!

trans·par·ent     (trns-pârnt, -pr-)     adj.
Capable of transmitting light so that objects or images can be seen as if there were no intervening material.

trans·lu·cent     (trns-lsnt, trnz-)     adj.
Transmitting light but causing sufficient diffusion to prevent perception of distinct images.

BRIAN PYLANT
Manager, Electronic Prepress
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   Date: Wed, 21 Sep 2005 15:19:29 +0300
   From: Toby Macklin
Subject: dayglo green

Thanks everyone who gave advice on how to set up my dayglo green book cover.

Finally did it with the text knocking out of one layer of green and overprinting the other. Looks pretty good.

Toby