Colour issues when UV Printing

[LN12]

Hi,

Any help or ideas greatly appreciated!

I have been designing in Affinity and UV Printing onto Lego figures. Sometimes a colour will print as expected and then on the next print will come out quite differently, or vice versa. For example, in the attached picture, the brown on the front of the legs was printed first, then what should have been the same brown printed lighter and less bright on the side of the legs. The designs used for the front and side prints were created in the same file with exactly the same colour values, and were exported to pdf with the same export settings. I tried scraping the ink off the side of the legs, re-exported the design and reprinted but with the same result. 

I have seen this numerous times, with various different colours, but it doesn't seem to occur uniformly, eg I've had it happen with a shade of grey I use several times, but it has printed correctly on all sides several times as well.

Obviously I'm looking at the printer as the source of these problems (though everyone I've spoken too has no idea as to why the printer would cause - I don't change any settings between prints), but am wondering if there could be something happening in the export that is causing it?

 

[Hangman]

Hi @LN12 and welcome to the forums,

Can you upload the PDF(s) you created so we can check whether there is anything obviously wrong with the exported file(s)?

[LN12]

reprint side legs double white.pdf1 Torso double white.pdf

Thanks @Hangman!

Files attached

[Hangman]

Hi @LN12,

Thanks for the files...

There's certainly nothing obvious with the PDF files which would seem to suggest weirdly, a printer issue though I'm slightly unsure what that issue would be since the colour variation is so different...

[Ldina]

@LN12 Opening your PDF files in Affinity Photo reveals the same exact color numbers in both brown objects. Same with Preview.

I opened both of your PDFs using Acrobat Pro (old CS6 version). Again, the colors are the same, but I did note one difference. Your front view shows a "Non-Knockout Transparency Group" set to sRGB Transparency Blend Space. The other view does not have this transparency blend group. I'm not sure if that is what is causing your issue, but it might be. Worth looking into. See screenshots attached. 

 

reprint side legs double white.pdf

[thomaso]

52 minutes ago, Ldina said:

sRGB Transparency Blend Space

This seems to be caused by transparency in the yellow elements, in particular by a layer effect (shadow/3D/) on some items.

But I'm wondering about the profile in the OP's PDF (-> @Ldina's screenshot), which seems to be used by Affinity V2 as blend space profile. – Did the blend space profile generally change between V1 and V2 – or is it influenced by a document setting in V2 or of @LN12? 

In V1 the blend space profile profile is the "typical" profile named "sRGB IEC61966-2.1" (and may confuse in particular in CMYK document) … whereas in the OP's pdf the blend space profile is named "sRGB2014" which is a different one, according to the link below.

https://www.color.org/srgbprofiles.xalter/profiles/sRGB2014.icc#v2

I remember a forums thread were this "sRGB2014" profile came up as a solution for a user problem, unfortunately I can't remember the details. But a forum search for "sRGB2014" finds several threads, most of them regarding a bug regarding unprofiled images, for instance:

[Ldina]

6 minutes ago, thomaso said:

This seems to be caused by transparency in the yellow elements, in particular by a layer effect (shadow/3D/) on some items.

Thanks, @thomaso...I was hoping you would comment on this.

To the best of my recollection, Publisher does not allow the user to specify separate RGB and CMYK Transparency Blend Spaces. In my testing a few years ago, I sometimes noticed RGB Transparency Blend Spaces showing up inside CMYK documents exported from Publisher (viewed using Acrobat Pro). That seems wrong to me and can result in different colors than using a CMYK Blend Space. I've used Publisher a fair amount, but for any jobs headed to Press. All my press work was done using....you know who!

[Ldina]

@LN12 I opened your Torso PDF file in Acrobat X Pro and ran a "Transparency Flattening - Hi Resolution fixup" on it, then saved it with "fixup" appended to the filename. You should check this file carefully to make sure it looks the same as your original, but I believe this eliminated any transparency and removed that RGB Transparency Blend Space from the PDF file. I agree with @thomaso that the culprit was probably that yellow belt element, or whatever it was, because it was the only item that showed up when running an analysis for "transparency". I hope this resolves your issue. I'd try printing to a desktop printer first, preferably one that uses a RIP (if you have one), and compare the colors in the two files, before sending it to production. I haven't done this in a while, so no guarantees, but I suspect that's the issue. 

@thomaso I'm not sure when the sRGB2014 profile snuck in or how. Maybe Serif switched to that at some point, as it's a newer profile? I seem to recall a similar discussion about the 2014 profile, but I forget the context. I keep everything set to the old standby, "sRGB IEC61966-2.1". I know that in some of my testing, I noticed RGB Transparency Blend Spaces were used in exported PDF files, even with CMYK originals. Perhaps when Blurs, gradients, transparency, etc, are used, Publisher uses RGB as the blend space and exports it as such. Like I mentioned, I'm a bit out of my element because I've never sent a job to Press using APub, so I will defer to those with more direct experience. 

1 Torso double white-fixup.pdf

[thomaso]

42 minutes ago, Ldina said:

I agree with @thomaso that the culprit was probably that yellow belt element

I did not mean that the transparency blend space profile is involved in the OP's colour issue. I was just wondering about this profile since you mentioned it in your screenshot. I don't know if the blend space profile can/does influence any object which doesn't have transparency (like the OP's brown elements in question).

46 minutes ago, Ldina said:

I'm not sure when the sRGB2014 profile snuck in or how. Maybe Serif switched to that at some point, as it's a newer profile?

Possibly by the bug (linked above)? @LN12, what Affinity version did you use when exporting these two PDF?

@Ldina, you can check if Affinity generally switched the transparency blend space profile in V2 by exporting a test PDF with transparency. I would expect if this profile was changed by Serif on purpose, also the sRGB profile in the default colour preferences of V2 would have been replaced, – was it?

[Ldina]

1 hour ago, thomaso said:

@Ldina, you can check if Affinity generally switched the transparency blend space profile in V2 by exporting a test PDF with transparency. I would expect if this profile was changed by Serif on purpose, also the sRGB profile in the default colour preferences of V2 would have been replaced, – was it?

@thomaso I just exported the attached file from Publisher 2.5.7 using the standard Press Ready PDF preset. (Original file was created with Designer and had a transparent background instead of white). This was a test file I created a few years ago to help me understand what was going on with the various PDF export choices, vectors, transparency, profiles, rasterization, etc. The original file was a mixed mode (RGB & CMYK) file, with some drop shadows, Divide blend mode, etc. The file was created and saved as CMYK/8, and my settings in all three Affinity Apps are... RGB: Display P3, CMYK: US Web Coated (SWOP) v2. EDIT: I did NOT use Divide Blend Mode...I used Boolean Divide to separate some of the shapes during testing! Typo.

Viewed in Acrobat 10 Pro, the exported PDF file shows an sRGB 2014 RGB Transparency Blend Space for ALL objects (using Object Inspector), not just the ones that used transparency or drop shadows. Maybe that's because the document itself has a transparent background instead of white? I don't use sRGB2014 for anything (at least knowingly). I don't know what Serif's "default" RGB profile is in settings. I've used Display P3 as my default RGB color space for a long time. At any rate, sRGB2014 was applied during PDF export, I assume by default.

Let me know if you need a file that is constructed differently (or better yet, upload a suitable v1 file, and I will open and export from v2.5.7).

1 hour ago, thomaso said:

I don't know if the blend space profile can/does influence any object which doesn't have transparency (like the OP's brown elements in question).

I don't know either. I assume it will affect any objects (text, vector, images, etc) that involve blending one layer with another. In that case, it appears RGB Transparency Blend Space is used, and not CMYK Transparency Blend Space. From my experience with InDesign, that can make a difference. 

Test-mixed mode CMYK - with Shadow-Press Ready PDF.pdf

[LN12]

Thank you all for your input. I don't understand most of the detail, but I think I get the idea - the 3D effect is causing this transparency blend group, which may be causing the colour difference.

Having looked back at the files where I had a similar problem the 3D effect is the common theme (with what I think is one exception), so that does seem to be the cause.

I've attached the file of the one exception which I can see from Acrobat also has the Non-knockout Transparency Blend group @thomaso please could you see what is causing it in this one?

21 hours ago, thomaso said:

Possibly by the bug (linked above)? @LN12, what Affinity version did you use when exporting these two PDF?

I'm using version 2.5.7.

22 hours ago, Ldina said:

@LN12 I opened your Torso PDF file in Acrobat X Pro and ran a "Transparency Flattening - Hi Resolution fixup" on it, then saved it with "fixup" appended to the filename. You should check this file carefully to make sure it looks the same as your original, but I believe this eliminated any transparency and removed that RGB Transparency Blend Space from the PDF file. I agree with @thomaso that the culprit was probably that yellow belt element, or whatever it was, because it was the only item that showed up when running an analysis for "transparency". I hope this resolves your issue. I'd try printing to a desktop printer first, preferably one that uses a RIP (if you have one), and compare the colors in the two files, before sending it to production. I haven't done this in a while, so no guarantees, but I suspect that's the issue. 
723.08 kB · 1 download

@Ldina thank you very much for this. Is there a way in Affinity to avoid this at all? (other than the obvious of not using the 3D effects) Some setting when exporting? I wasn't planning on getting the full version of Acrobat!

Set 8 July 2 torso.pdf

[Ldina]

@LN12 The only "transparent" object I could find in your file (using Acrobat 10 Pro),is the yellow-brown oval shape shown below. So, some effect was probably applied to this object. 

I'm not sure I'm the best person to help you with this. It's been a while since I did this type of work, and I don't want to lead you astray. I do have a few thoughts and questions, however, which may help me, or others, provide helpful guidance. I can see from the PDF that you created this in Designer v2.5.7 and exported to PDF version 1.7.

1. Can you provide a screenshot of your PDF Export settings? (i.e., the entire PDF export window with all the boxes and fields you checked). Use two screenshots if it won't all fit in one screenshot.
2. Are you exporting individual images from this design to the printer, and do they need to be vector based, or is it okay to send raster data (pixel-based bitmap files)? 
3. I assume you need the white background shown in the PDF file to be fully transparent, and that your Designer file uses a transparent background?
4. It would probably help us if you can upload your original Designer file, along with ALL linked elements, so forum members can review it. This should help us to identify the issue. Make sure you ZIP everything before uploading. (Or, you can "embed" any placed, external elements, using Resource Manager, highlighting any linked files, and clicking on the EMBED button. This will embed all linked elements in your Designer file and guarantee they are included if you upload it to the forum.)

It is likely something in the original file, or your PDF export settings that is causing the problem. 

[Ldina]

@LN12 A little more information...

I opened your most recent PDF export into Designer v2.5.7. I'm not positive if what comes into Designer is an exact duplicate of your original Designer file or not. I'm guessing Designer does its best to preserve objects, colors, layer structure, etc. 

That yellow-brown oval mentioned in my last post definitely has some transparency, as shown in the following screenshot. I'm assuming this object (and two others) were placed into your Designer file. This oval is the only one that seems to have any transparency. I found these "images" inside of Designer by going to Select > Select Objects > Images, which highlight this object and two others. You can see that they are embedded in Designer by going to Window > Resource Manager. Whether they were linked or embedded in your original Designer file, I don't know, but they were exported when you created your PDF, so they loaded as embedded objects when I opened your PDF. 

At any rate, you definitely have some aliased edges (partial transparency) in that yellow oval. I'd try recreating and replacing that object using vectors, insuring that you do not have any transparency. Then, delete the original "image" with the antialiased edges. I'd do the same with the two small brown gradients in the 6th object from the left (which also show up in the file as "Images"). If that works, you've identified and solved your problem. 

Hope that helps. 

[thomaso]

Am 18.01.2025 um 02:44 Uhr sagte Ldina:

Maybe that's because the document itself has a transparent background instead of white?

Hardly. Usually a PDF has a transparent background (displayed as white page).

Vor 4 Stunden sagte LN12:

Is there a way in Affinity to avoid this at all? (other than the obvious of not using the 3D effects) Some setting when exporting?

You can avoid the creation of the "Transparency blend space profile" in the exported PDF by avoiding transparency. To do this, you can either rasterize these layers before export or choose in the export settings "Rasterise: Everything" (which will rasterize every object, not only those with transparency).

[Ldina]

@LN12 I think it may have your issue solved (I hope).

I've attached two files. I opened your PDF using Designer, deleted the 3 "images" and the two masks you used for the brown stripes. I replaced all three objects with newly created vector objects, created in Designer. I hope Designer opened and interpreted your PDF correctly. Even so, it would probably best best to work from your original Designer file.

The good news is that when I exported to Press Ready PDF, the dialog box opened saying "Nothing will be rasterized". That was a good sign. That was not the case with your original files. I exported the PDF and looked at it in Acrobat Pro and didn't find any transparency, and no transparency blend spaces. So, hopefully, this was the cause of your color shift problems, and if so, it should be solved.

Please let us know one way or the other, so others can benefit from this discussion.

Thank you, @thomaso. Your message came in just as I was finishing writing this. I asked the OP about whether he could use raster images for that reason. I appreciate the confirmation.  

Set 8 July 2 torso-edit2.pdf Set 8 July 2 torso-edited.afdesign

[LN12]

@Ldina @thomaso thank you for this.

@Ldina interestingly the three shapes you amended were created in Designer, with a colour gradient - I've exported another file with some gradients in, then opened up the pdf and can see that these shapes always show up as an image layer. Clearly these gradients cause the same issue as the 3d Effects.

I will be printing again in a couple of weeks so will test out rasterizing and/or removing these effects, and feedback then.

Thanks again for your help, I strongly suspect this will solve my overall colour issues.

[Ldina]

4 hours ago, LN12 said:

 interestingly the three shapes you amended were created in Designer, with a colour gradient - I've exported another file with some gradients in, then opened up the pdf and can see that these shapes always show up as an image layer. Clearly these gradients cause the same issue as the 3d Effects.

There may be a few factors at play...I used a Linear Gradient. I'm not sure if Radial, Elliptical and other gradients are treated differently. I can't remember, but it seems to me some of your gradients were Radial or Elliptical? I suspect linear gradients are most likely supported by PDF. Many things like blurs, gradients, 3D effects, shadows, Inner Glow, etc, rely on raster effects and result in gradual blending of one color into another, so if they are rasterized and reimported into Designer, they may come in as "Images".

4 hours ago, LN12 said:

I will be printing again in a couple of weeks so will test out rasterizing and/or removing these effects, and feedback then.

It's ALWAYS a good idea to obtain detailed requirements from your printer on their PDF submission requirements and how they should be prepared. Things like DPI, Color Space, whether to embed profiles or not, Output Intent, whether they allow transparency or require a flattened file, and what "flavor" of PDF they want (PDF/X-1a, PDF/X-4, etc). Most printers have a prepared document or specification outlining their requirements to assist clients and to make sure they receive a file that prints well in their system. If you adhere to their guidelines and prepare the PDF properly, you're more likely to get predictable results. Also, as Thomaso mentioned, you can rasterize the file and flatten it to take transparency out of the equation, but you'll have a raster file, not a vector file.