white overprint

[stefanofe]

I need to print on cardboard in white and 2 other colors. Black, pantone, white. Each of these colors must be overprinted. I can't define white though. If I put a fifth white color rgb or cmyk and then overprint, on the sheet it disappears when I create the pdf. On the one hand I understand that overprinting white does not return anything, but we are talking about a fifth color so this approach does not make sense. Can anyone help me with this?
I tried creating a fifth color c1 m1 y1 k1 to see if it changed anything by assigning a minimum value for each channel, but this is not the solution. I would like to have on the pdf if I deselect the "white" channel the elements disappear as with the other colors and reappear when I reactivate it, but white always punctures my underlying layers and if I deselect it nothing happens--because it punctures the color layers.

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[BobLevine]

Just create any spot swatch you want and tell the printer to sub it out with the white ink. But why are overprinting it?

[James Gifford—NitroPress]

I suspect it's printing on brown cardboard, like for bulk product packaging. It's a PITA in many ways.

I agree, though, just create a spot color that's NOT a pure white, and define it so the plate exports with a WHITE label for the printer.

[stefanofe]

I overprint because I have to overprint! It has to cover the black too!

[BobLevine]

You want white to cover black? That's going to be one hell of a trick.

[rob day]

It wouldn’t be a problem with screen printing.

[Derek Cross]

What colour is the card?

[stefanofe]

brownbrown. But the color of the paper has no bearing on the issue.

[Jeffrey_Smith]

Keep in mind if you are creating a spot color that is white, with overprint applied, and is over top of another element, the PDF in Acrobat (Overprint Preview) will dislay this in a way that will make the white disappear.

[stefanofe]

exactly this is the problem! But I turn to Adobe who is supposed to be the leader in the printing industry and they can't handle me an opaque white! And don't ask me to use cyan or another color! I say if I have an opaque white paint.... you have to know how to handle it: it is not a transparency: it is a color!
Photoshop was not born with transparency ... and now I can't handle spot colors?

[stefanofe]

I'm asking for a simple flag!!! You will understand what a great request!

[stefanofe]

exactly this. I tried, but I couldn't do it. c1 m1 y1 k1 - spot tint - overprint - and I have an empty channel. but I'm still trying. Anyway if I define as 5 color a white...why on earth do I have to assign values to the tints? This is a serious error by Adobe. The 5 color can also be a transparent lacquer!!!!

[James Gifford—NitroPress]

Both (some instances of) Black and (nearly all instances of) White are special cases in print graphics. It's inherent to assume that any use of white is meant to represent an absence of ink applied to (usually) white stock. I am not surprised you're getting stubbornly "normalized" results, and I'd bet there is no good ("official") way to bypass them.

Unless you are doing digital printing, where the color mix will be transferred directly to the printer — that is, assuming you're designing for plate and ink printing — just use a reasonable substitute color that the export system won't interpret as "white/blank" — something with enough defined tint to avoid that classification — and I suspect you'll have no further problems. It will be up to you to differentiate between a preview/proof image with white elements, and the export/RIP setup that will generate a proper "White" plate.

[stefanofe]

I disagree. Instead, I say that the preview must follow my intention. If I say that a text is white in overprint ... the white is no longer the white of the paper, but of a pigment. But you have to explain to me the difference that there can be between a cyan 100 dye and white 100 for a software. I told you. a simple flag is enough! Just put it on though. The flag tells the software that I want an opaque tint.

[stefanofe]

If the world dictates brown paper and white printing... Adobe can't sleep!

[James Gifford—NitroPress]

No one here is saying it's "correct" or even acceptable. But it is what it is, so (as with so may other very fringe situations in this complex field), you can apply a workaround and move on, or... go see if MS Publisher or Affinity Publisher does a better job for you. But snarling at other users who are here to help you through the problem isn't all that productive.

[stefanofe]

chiedo scusa. Non ero arrabbiato con te e mi rendo conto di essere stato aggressivo involontariamente. Io mi domando come mai Adobe non sappia gestire questo. Voglio seguire il tuo consiglio e vedere se Affinity mi ascolta. Di solito sì. Però se lo fa, sono certo che Adobe non può solo prenderne atto, ma deve intervenire... direi con un semplicissimo flag sul bianco.

[rob day · Accepted solution]

Hi @stefanofe , This has been a long running problem with InDesign (and Illustrator). There is no color management for Spot color overprints or tints in either application, so for Spot color output where the inks might be opaque, like screen printing, you have to ignore the Overprint Preview and check the separations in Separation Preview.

Here my [Paper] swatch is set to simulate cardboard, and with OP turned on my White Spot fill is displaying as transparent, as is PANTONE 3514, which is what would happen on an offset press where process as well as Pantone inks are transparent:

I have to check the Separation Preview for White Spot to confirm that with a separated output the fill is indeed overprinting

Photoshop does have some crude color mangement for Spot Channels—you can set the solidity of the spot ink and dot gain for tints—so if a better, somewhat color managed, preview matters you could work in Photoshop. Here I have my Spot Channel Options Solidity set to 80%.

[Derek Cross]

Litho and letterpress inks are semi-transparent, so you can't print opaque white – you can print opaque white with the screen printing process and with white blocking but these processes are not normally suitable for packaging.

[stefanofe]

Thank you

[rob day]

I told you. a simple flag is enough!

The feature request would be to add Photoshop’s Spot Channel Options Solidity setting to InDesign‘s Swatch Options when the Color Type is Spot.

There has been no ink opacity setting in InDesign, AI or Acrobat for over 20 years, so I’m guessing it won‘t happen, but I agree it would be a useful feature when the output can handle opaque inks, or for foil applications.

[Jeffrey_Smith]

There are times in graphic design that one may need to create a file to simulate the results of final intent, and then create a completely different file that would suffice the production needs of overprinting, proper color separation etc.

[stefanofe]

in some cases this is complex to achieve... I am in one of these cases.

[Peter Spier]

This seems like a great feature request....

When the [Paper] color is redifined to match colored stock, allow a white spot color.

[Peter Spier]

In the meantime, if this is just to get a proper visual preview as Jeffrey suggests, a second file with a colored background and white elements using [Paper] might suffice.