Spot colors and gradients?

[tmiller_iluvprinting]

We all know that spot colors and gradients do not play well together. Color shifts, graying, intensity changes are a few of the issues that arise when a gradient and spot color are introduced. Does anybody have a good explanation why this happens? Thank you!
Regards,
Todd

 

[leonardr]

We all know that spot colors and gradients do not play well together. Color shifts, graying, intensity changes are a few of the issues that arise when a gradient and spot color are introduced.

I am not aware of any such problems.

What software are you using to create these spot color-based gradients?

Are you seeing problems on teh screen?

Are you seeing problems at print time? Did you print directly from the application? If not, then how did you print?

Please help us help you by explaining exactly what seems to be the problem..

 

[gordo]

We all know that spot colors and gradients do not play well together. Color shifts, graying, intensity changes are a few of the issues that arise when a gradient and spot color are introduced. Does anybody have a good explanation why this happens? Thank you!
Regards,
Todd

This is correct - at least for Pantone spot colors. The reason is that those spot colors were originally defined to be used for solid color printing (not screened, not wet trapped). As a result, the pigment and ink formulations may be problematic if you screen or wet trap them. Sometimes there's no problem. But sometimes it's a disaster.
The key is to tell your ink vendor how you are going to be printing the particular spot color. They can reformulate the ink for better print ability.

Best gordo

 

[charles09]

On digital engines, aren't there issues with ripping to postscript vs. the new Adobe PDF Print Engine? I had thought that APPE did a better job with this but I could be wrong. What do you think Gordo?

 

[gordo]

On digital engines, aren't there issues with ripping to postscript vs. the new Adobe PDF Print Engine? I had thought that APPE did a better job with this but I could be wrong. What do you think Gordo?

I was referring to ink on paper not what happens in workflow. Are you talking about gradients of spot colors that are simulated out of process colors?

Best gordo

 

[David Milisock]

Spot color and gradients

Spot color and gradients

We all know that spot colors and gradients do not play well together. Color shifts, graying, intensity changes are a few of the issues that arise when a gradient and spot color are introduced. Does anybody have a good explanation why this happens? Thank you!
Regards,
Todd

There can be several issues with spot colors and gradients, the first being that the RIP may have limited support for such output. Most of the issues I see now are related to the user creating what they think is a spot color gradient while instead they are using spot color transparency instead of a true spot color gradient.

These objects transparent become N color space items and depending on the RIP and output requirement may not be supported. This, in my experience is an extreme problem with Adobe users due to the poor training available today, especially when the file is saved as a PDF instead of created as a PS file and then Distilled. Which happens to resolve the issue in many cases.

In any cases that I've seen for plate setters true spot color gradients seem to work fine but digital output can be interesting but usuaslly through experience predictable.

While the use of transparency with spot colors is, in my experience a hands on experience and only as good as the technician. I have done over 100 different label types with print quantities in excess of 4 million labels, they were originaly created in Illustrator 5 to be 1 to 3 spot colors by a completely inexperienced user and the only way to make them work as spot color was to take them to CorelDRAW, some were done in X5 some in X6 but they turned out just fine after a large billing to the client to fix the files.

 

[rich apollo]

In short, color doesn't simply move in a straight line from paper white to solid. There are hue shifts and changes in L* and a changing contribution of the paper white to the perceived color; and that's with a single ink. Most folks haven't gathered enough data to be able to accurately predict what will happen to a spot color thoughout the tone scale. Without measuring these characteristics, we're just guessing.

Take a look at the attached screen grab. These are the primaries from a hex profile I got hold of. Notice the non-linearity going from paper to solid.

One thing that I suggest is that draw-downs be made for the whole tonal range. Shouldn't be tough to do with say a little-Joe press and a flexo blanket.

When building ICC profiles, A LOT of combinations of screens are printed and measured. To accurately proof blends of spot colors, these blends would need to be printed and measured.

 

[Al Ferrari]

Hi Rich,

"One thing that I suggest is that draw-downs be made for the whole tonal range. Shouldn't be tough to do with say a little-Joe press and a flexo blanket."

Is "draw-downs" really the term you intended here? How would that method lend itself to evaluating "the whole tonal range?"

Al

 

[rich apollo]

Hey, Al. I suppose that one could take issue with the term "draw-down", but I'm not sure what other term to use. I guess you're thinking of draw-downs being done with an ink-knife, but that's not the only way to do 'em.

My idea is to have something like a little-Joe and have a step wedge on the inking surface. I've seen examples where companies have their logo reversed out of the draw-down, so I think it's gotta' be possible.

 

[Al Ferrari]

Hi Rich,

You are right that I was thinking of the ink knife method. I have since spoken with the pressman here and he explained that the term is also used for the method you describe. I learned something.

Thanks,

Al