Question Weird transparency on printed vouchers

[Alex R.]

Hi guys,

I designed a voucher(in Illustrator) for a client of mine, saved it as PDF(with PDF/X-4:2010 standard) and sent it to a printer(we don't do small printing).
And as you can see on the attached image(I also attached pdf file that I sent to our printer), black colour(100% Key) that overlaps with white background became transparent.
Any idea why it happened? I need to know that not for finding an escape goat but to learn about it and to prevent that happening next time.

What's interesting is, if you zoom it, you can see how the outside black stroke on the cat's face came out transparent on the white background as well however seemingly solid on the outside area. And that makes me think that the whole black colour has some level of transparency. Where could it come from? All my layers are 100%

Thank you in advance

 

[aGrainofSalt]

Sorry, I've not a lot of time to look into the file. When I release your clipping mask, there are mixed overprint fill and stroke items checked. It appears that the black is 100% opaque, and I don't see transparency effects at first glance. This does look like an overprint though, the black is just "blacker" over the teal color, similar to doing a heavy build black, or rich black.

 

[Marie]

I looked at that PDF in Illustrator and the black fills and strokes are both 100%, and I don't see any transparency either - strange problem. In CMYK printing, using a rich black (80, 80, 80, 100) usually prints a deeper/darker black. Maybe printing in rich black would take away the transparent look?? Also you could convert your strokes to outlines so that you could combine the cup and the outline of the cat so that they print as one color unit. Just a few thoughts.

 

[Alex R.]

Thank you guys very much for chipping in. So you reckon it's something weird happened with the way my printer separated colours? Cause when I do check separation overprint preview with rich black it creates(obviously) two different separations.
It's strange I never come across such issues before with them.
Maybe it is a safe way to always use rich black for third-party printers. In our shop, we use 100% key on Roland VSi printers simply cuz it saves a lot of inks. I guess for offset printing that's not favourable?

 

[Solventinkjet]

My theory is that rendering intents are the culprit. There is an RGB image in the background which is hidden by a clipping mask. The way the head of the cat is made is weird. It looks like a white circle with a black outline but in reality it's a white circle with another clear circle on top that has a black outline. This is where the problem is. A transparency that has RGB data behind it. Most RIPs default to handling CMYK and RGB images differently via the rendering intents settings. So when you mix them together and add a transparency to the mix, the RIP processes the same area twice which creates weird anomalies. Try taking that RGB image out of the file and see what happens. Or just delete 1 of the circles and make the other white with a black outline.

 

[Alex R.]

My theory is that rendering intents are the culprit. There is an RGB image in the background which is hidden by a clipping mask. The way the head of the cat is made is weird. It looks like a white circle with a black outline but in reality it's a white circle with another clear circle on top that has a black outline. This is where the problem is. A transparency that has RGB data behind it. Most RIPs default to handling CMYK and RGB images differently via the rendering intents settings. So when you mix them together and add a transparency to the mix, the RIP processes the same area twice which creates weird anomalies. Try taking that RGB image out of the file and see what happens. Or just delete 1 of the circles and make the other white with a black outline.

The cat firstly was made in Corel. Saved in PDF. From there I just copied to over into my artwork. all cat's outlines are separate layers. But I fail to see how could that affect separation?

 

[Solventinkjet]

The cat firstly was made in Corel. Saved in PDF. From there I just copied to over into my artwork. all cat's outlines are separate layers. But I fail to see how could that affect separation?

The outline and fill being in different layers is what is causing the issue along with the fact that there is an RGB image in the file behind it. Every object that lies within the transparent circle is going to look faded. So you could put a yellow star on the cat's face and it would look washed out just like the black part of the cup the overlaps it. The reason is because the RGB image in the background is causing the RIP to process that area twice. The RIP is trying to process the transparent circle but because RGB and CMYK color spaces get handled differently in RIPs, you get conflicts. Try it out and see what happens. You might be surprised.

 

[shoresigns]

My theory is that rendering intents are the culprit. There is an RGB image in the background which is hidden by a clipping mask. The way the head of the cat is made is weird. It looks like a white circle with a black outline but in reality it's a white circle with another clear circle on top that has a black outline. This is where the problem is. A transparency that has RGB data behind it. Most RIPs default to handling CMYK and RGB images differently via the rendering intents settings. So when you mix them together and add a transparency to the mix, the RIP processes the same area twice which creates weird anomalies. Try taking that RGB image out of the file and see what happens. Or just delete 1 of the circles and make the other white with a black outline.

The outline and fill being in different layers is what is causing the issue along with the fact that there is an RGB image in the file behind it. Every object that lies within the transparent circle is going to look faded. So you could put a yellow star on the cat's face and it would look washed out just like the black part of the cup the overlaps it. The reason is because the RGB image in the background is causing the RIP to process that area twice. The RIP is trying to process the transparent circle but because RGB and CMYK color spaces get handled differently in RIPs, you get conflicts. Try it out and see what happens. You might be surprised.

All objects including the raster image are CMYK and there are no transparencies present in the PDF.

You might still be right about rendering intents being the culprit, though. Rendering intents can apply to images and vectors differently. OP, check your rendering intents for raster vs. vector in your RIP. If they're different, make them the same, and that will likely solve the problem.

I'm not 100% sure that's the problem either, though. It's a bit weird that the problem is restricted to that white circle, which doesn't seem to have anything unusual about it compared with the other vector objects. It could just be a bug in how your RIP is interpreting this PDF file.

 

[Solventinkjet]

I'm not 100% sure that's the problem either, though. It's a bit weird that the problem is restricted to that white circle, which doesn't seem to have anything unusual about it compared with the other vector objects.

It's not just a white circle. It's a white circle with another transparent circle on top which has a black outline. That's where the transparency is. Also, you are right on the image being CMYK but rendering intents do also discriminate between vector and bitmap as well which is the case here.

 

[shoresigns]

It's not just a white circle. It's a white circle with another transparent circle on top which has a black outline. That's where the transparency is. Also, you are right on the image being CMYK but rendering intents do also discriminate between vector and bitmap as well which is the case here.

It's two circles, one with a black stroke and the other with a white fill. There is no transparency anywhere in the PDF, if we're using the correct terminology. Transparency is when an object has an alpha channel or an opacity less than 100%, so that the colour blends with any objects below it. The circle with the black stroke doesn't have a transparent fill – it has no fill.

You can easily check a PDF to see if any transparency exists on an entire page by using Output Preview:

 

[Solventinkjet]

It's two circles, one with a black stroke and the other with a white fill. There is no transparency anywhere in the PDF, if we're using the correct terminology. Transparency is when an object has an alpha channel or an opacity less than 100%, so that the colour blends with any objects below it. The circle with the black stroke doesn't have a transparent fill – it has no fill.

You can easily check a PDF to see if any transparency exists on an entire page by using Output Preview:
View attachment 137176

The RIP is seeing the no fill as a transparency in this case. Look at OP's original printed image and zoom in. The only places where the black is washed out is the boundaries of the transparent circle. Notice how the outside edges of the black outline are not washed out? It's because the black stroke is centered on the vector so half of the stroke is overlapping the no fill circle and is washed out but the other half that isn't overlapping the no fill circle is perfectly fine.

 

[VizualVoice]

It sounds like you're dealing with a tricky printing issue! From what you described, it seems like there might be an unexpected transparency issue with the black color in your design.

Nice first post, Mr. AI.
We anxiously await your next one which will likely contain some form of spiced, preserved ham product.

 

[TumwaterTom]

It seems like whatever RIP was used to raster the art for printing is set to overprint areas of 100 K (which is usually a setting that can be turned on or off on a per file basis, but tends to be set to on).
I opened it in Illustrator and set all the black to Overprint and it looks like your sample.