Hi, I am making a "book" for printing through the Blurb people. I did a small test print and I have noticed a problem. I have some transparent PNG graphics in my book created with Xara (a graphics program). I have a problem with them on the COVER (not the inside of the book). The PNGs look OK in Xara and InDesign, and they look OK in the actual PDFs that went to Blurb to print from, but in the hardcopy of the book I received, the area around the PNGs on the cover are slightly lighter than the dark grey background they are on. The PNGs inside the book look OK on the same dark grey background.
Scan of printed cover problem area (above). Hard to see but there's an area of color around the graphic that should not be there.
Screen shot of image as it looks everywhere other than the hardcopy of book (above)
Screen shot of inside page w/PNG graphic that's OK (above). Text is InDesign text on top of the PNG and is not part of the graphic. It looks just like this (correct) in the printed book.
From what I've read here and elsewhere, apparently I should not use PNGs for print, is that correct? What I want is the simplest solution that solves the problem. I want to use the graphics already developed in Xara. Those graphics are vector based, but since I've added shadows and gradients I want to stay with raster images exported with transparency (not vector).
Here's what I've tried and seems to work (by that I mean, this all works on screen. I'll need to do another proof copy of the book to check it): I can export from Xara to PSD. Graphics look fine, transparency is correct and intact. I can open that PSD in Photoshop, then from PS I can save a transparent TIF file. I've tried this and it works OK; the transparent TIF places in InDesign just fine and looks identical to the PNGs in there now.
My question would be does this sound like it will fix the final printing issue? Second question: why did the PNGs inside the book work? Is it because I placed white InDesign text on top of those?
Thanks in advance.
What does Blurb say in their documentation about graphic file format support? Do the have technical support?
It's definitely NOT an InDesign issue, it's a Blurb issue.
They have some support but it takes a very long time to get anything from them. I have asked about this on their forum which the support people read but no answers from them yet. The odd thing is, Blurb prints from a PDF, not the InDesign file, and the actual PDF I uploaded to them looks fine. At least, it looks OK on screen but not when printed. I'll keep trying to get hold of someone there.
I'm not saying my following points will answer your issue but from a workflow point of view they are worth bearing in mind
– PNG is not the best format for print; if you have access to Illustrator or Photoshop create your graphics in these applications and Place them as native PSD or AI files in your InDesign document.
– Certain colour won't translate from RGB to CMYK color modes (particularly bright greens and bright oranges). You may find that your bright blue cannot be produced in CMYK; it's worth checking.
Thanks. As to workflow, yes, it's easier just to save as PSD from Xara then open that in PS and then resave with max compatibility turned on from there. Imports into ID no problem and looks fine...on screen anyway!
Controversially, I will disagree with @Derek Cross PNG is perfectly fine for print, and used all the time in my InDesign workflow.
However, this is not an InDesign problem as correctly pointed out by @Steve Werner
In my experience your PNG needs to be PNG 24 for print - as PNG 8 doesn't handle transparency well.
I think this is the right screenshot from Xara - set the export to have 256 instead of 16.
I've read that about PNG 24 before. I have no options in Xara export other than true color + alpha, which, if I'm reading things correctly means they are already at PNG 24 but I could be wrong.
Anyway, if I open the original PNG files in PS, PS says they are RGB Color, 8 bits/channel. If I change the color mode to cmyk, I can then change bits to 8 or 16. Not sure if any of that would help or not though!
I appreciate the help. I'm not a "print guy," I mostly work with on-screen images. This print stuff baffles me sometimes!
Previous to getting my test print copy of the book, I had already changed my front cover into a single image with no transparency which should take care of that one. The back cover would still be an issue.
So one option with all this is to just change the back cover graphic so that it includes the background and covers the entire back cover area so I won't need transparency. I can also do this for any background graphics inside the book to ensure things look OK there.
I like the results from the Blurb people, but unfortunately they won't print one or two pages to proof things, you have to order a minimum 20 page "test book" every time. That was fine the first time around so I could check everything. But it would be very expensive to keep getting test books done just to test image transparency.
If I can get some sort of definitive answer from Blurb I'll post it here.
The PNGs look OK in Xara and InDesign, and they look OK in the actual PDFs that went to Blurb to print from
Can you share the PNG and PDF you sent to Blurb via Dropbox or your CC account? It looks more like a color management than a file format problem.
PNGs have to be in RGB mode, and it looks like you have placed them on a black only (0|0|0|100) CMYK background. A converted 0|0|0 RGB black would print differently than a 0|0|0|100 CMYK black. Blacks with different output numbers wouldn’t necessarily be obvious from the preview in Acrobat—you have to check the separation numbers.
The PNGs are on a 0|0|0|96 InDesign rectangle on the master page layer. The PNGs are transparent, they do not have any background as such.
I'd be glad to share the PDF. I'm not sure if this will work but here's a dropbox link:
If that fails let me know.
There doesn’t seem to be a problem with the PDF.
I can see that you exported to PDF/X-3, which flattens transparency, and the transparent PNG was flattened correctly—the output numbers for the dropshadow and the background are correct.
PDF/X-3 allows RGB objects, but you set the Output tab to Convert to CMYK. The only thing I can think of is the Blurb output device is seeing a difference between the logo bitmap and the InDesign vector background, but you shouldn‘t have to worry about that.
Also, note that I don't care about using PNGs per se, I can save the original graphics as PSD and then import them into ID. If that will fix it that's fine! I have an older version of Acrobat Pro, I do not know how to check separation numbers or if my version will even do that.
I can save the original graphics as PSD and then import them into ID.
I agree with Eugene 24-bit PNGs are not a problem—when you export the original file format is lost all that matters for the PDF is the image resolution, color mode and bit depth.
AcrobatPro lets me inspect the page objects and you can see there is no file format listed, and in the case of your PDF there is no longer any transparency:
Also, you shouldn’t have to worry about this, but Object inspector shows the logo as an image, and the background as a vector. It could be that the output is to a composite printer and the printer color manages bitmaps and vectors differently. If you look closely at the scan you posted, you can see the 97% black background has been converted into 4-color, so your PDF output values are being converted.
Thanks for looking at it. I thought it all looked OK too so I'm not sure what's going on. One thing that really makes me wonder is the inside PNG background graphics worked, the ones on the cover did not. Maybe they use different printers, one for the inside pages and one for the covers.
I've been working on it today and I think what I'll do is use text and fonts to mimic the images I was using. The advantage to that is it will be easier to maintain and/or change later if needed.
Thanks again for the help, I really appreciate it.
You might want to have Blurb tech support look at your PDF—the change in color is obviously happening in their print driver or RIP, and not in the provided file.
I put a support call in to them on the 18th. Nothing back from them yet but I'll post what I find out.
In the meantime, I changed my approach to it all. I replicated the graphics I wanted in Illustrator. Then just copied from there into ID. I'm hoping that the graphics are now in ID as vector. They look really good on screen both in ID and in Acrobat. Using 200% zoom in the PDF I see no artifacts or any weirdness going on.
Also, the original PNG graphics I was using included text. So I dropped all the text out of the IL versions and used ID text instead. Again, trying to keeps things vector based if possible. Also easier to change and modify.
Here's what they finally sent to me today: "In looking at the project files, the print issue which caused the box around the text is the 96% K value used. When a single color like this is used, the printer is not able to blend the layers. Converting this from 96% to a CMYK mix of C72.90% M63.44% Y61.31% and K71.47% will correct this." He didn't specify exactly which object it was but it's probably the background rectangles on my master pages. Those are the only thing I could find set to 96% K.
They offered to reprint it which was nice, but it was just a test book. I've already sent 2 others in based on that one that have been printed. Since I don't have any transparent PNGs in those I'm hoping they will be OK. That's all that was wrong in the test book. I'll wait to see those and then decide what I'll do as far as reprinting anything.
If they can’t output the document’s 97% black that likely means all document CMYK colors are being converted to different values at output—you can see that happening in your printed proof. It might be better to use RGB colors and swatches and export to PDF/X-4 with no color conversion, and let the conversion at output be directly from the profiled RGB.