Created Spot conversion to Process

[Nivin]

We have a customer supplied file that has a Spot Color named "Special Orange" that was created with a 4-color process mix of cyan-0 / magenta-85 / yellow-100 / black-0. We needed to convert the Spot to Process to multiply into a grayscale photo under it, maintaining the exact color. When we convert to process, the mix stays the same, but the on-screen preview changes a lot.

Weirdly they have one spot fill (multiply/transparency 75%) over another spot file (multiple/transparency 75) over the grayscale. That shouldn't be an issue.

But why would a spot color created with a process mix change visually when converted to process?

TIA
Linda

 

[Tim-Ellis]

Hello Linda,

I have just tried this in Illustrator and get a similar difference when I go into overprint preview.

I've attached my test file here. I've marked the corners of the image so you can see the colour difference on screen between the area where the photo is sitting under the colour block.

When I print my separations everything is pretty much what I'd expect.

Spot Colours and Transparency can produce unexpected results. I had really odd results at first because my black and white image was actually RGB. Once I converted it to greyscale everything went ok.

Is this the same issue you are getting?

 

[Danny Whitehead]

What application are you making the conversion in? Has this 'Special Orange' ever actually been printed as a spot ink? Because if it has, it's unlikely that it actually matched a 0 85 100 0 process mix on your press, so you'll need a sample to match. I'd consider that to be the important issue, rather than the on-screen display.

 

[Macmann]

Leave it a spot color and overprint the house graphic-set it to multiply if need be.

 

[Nivin]

Went to a different computer, spot converted fine. Went back to my computer, weirdly conversion now works fine.

We had to turn just this one area to process. The "Special Orange" was printing as a spot elsewhere.

I'll post if I can figure out why one time is doesn't work, and one time it does.

 

[Nivin]

I had time to try this again today. Everything looks ok until I turn on Separations Preview. The colors do not match. Tried setting up another Spot color named differently (just to make sure the color had not been previously defined in the library). Visually the colors from Spot to Process still did not match.

I Exported to PDF. Visually they look different, but both say Magenta 85, Yellow 100 (although one is spot and one is process).

I attached a PDF to hopefully show what I'm seeing.

 

[Tim-Ellis]

Hello Linda,

I don't think you have a real print problem here.

"Spot Colours and Transparency can produce unexpected results."


Have a look at the attached screenshot. I put a block of Special Orange at a 75% tint next to the shapes. The colour looks ok compared to the Special Orange with 75% transparency

The printed sheet will be printed will a screen of dots at a 75% tint, not as a "transparency"

On screen you are looking at RGB interpretation of a CMYK "transparency" and a spot colour "transparency"

​​​​​​I think the difference is just the software trying to render the image.

Print your job to separations and I think you will see it is just fine.

 

[Danny Whitehead]

Print your job to separations and I think you will see it is just fine.

Presuming the CMYK conversion is a match for how the spot colour actually prints, which to me sounds like the real challenge that's being missed amidst relatively superficial concerns about on-screen appearance.

 

[Nivin]

I believe you are correct. I created a PDF with the area duped. One Spot. One Process. Then used PitStop to convert to All Spots to Process. They look the same.

Moving on . . .

 

[Danny Whitehead]

They won't on press.

 

[Tim-Ellis]

Presuming the CMYK conversion is a match for how the spot colour actually prints, which to me sounds like the real challenge that's being missed amidst relatively superficial concerns about on-screen appearance.

Hello Linda,

Danny makes a very valid point here. (twice!)

I've assumed from the start that your customer knows you are printing CMYK only. That your customer is providing you with their chosen CMYK breakdown for Special Orange.

If your customer is expecting a 5 colour job they might not like the outcome. If the Special Orange they expect is bright and zingy and well outside of the CMYK Gamut then you might have a problem.

cyan-0 / magenta-85 / yellow-100 / black-0 could just be a CMYK build chosen almost at random. In the same way as you might mix up a spot colour with a CMYK build for "Clear UV Gloss Varnish"


Hopefully you are following the customers instruction. If not, make sure they sign off on a CMYK proof.

Good Luck.

 

[Abul kader]

You can google it!