Hello all,
I am designing various posters and adverts for print in CMYK using the CMYK profile in CorelDraw 2020 with proof colours turned on. I often lay gradients and transparencies over jpgs and my own vector designs. I have ensured my gradient mid points are at 50% and I've activated smooth transition.
When I export the files to PDF, using ISO Coasted v (ECI) embedded and all text exported as curves
1. My PDF file sizes can be absolutely huge, such as 100MB or even 800MB.
2. The transparencies drop out or are rendered differently in different programs eg. MS Edge to Acrobat Pro.
3. One print shop called to say that they could see the edges of all my gradient shape layers even if the gradient was 100% transparent at or well before the edge.
ORIGINAL COREL VECTOR - the white trims are all vector 100 to 0 % gradients laid over a colour gradient layer.
ADOBE ACROBAT PDF losing the transparency (MS Edge looks as good as the original)
If I convert this design to BMP is loses it beautiful crispness and the PDF file size rockets higher still.
There's been some excellent guidance on this forum about these sorts of issues but nothing has helped to resolve my particular issue. I'm sure there's a guru out there who'll swat this in a single blow.
Thanks everyone.
Jim
Ok there are several things about PDF files and rendering VS what you see on screen. First do you have proof colors turned on while designing? You should and have it set to proof your CMYK profile. Nuanced transitions will be different in output than on screen with color proofing turned off. It will always be a bit different even with it turned on but with proofing turned on it can be manipulated in the application.
Second print shops do not all have the same RIP. If you are taking your CorelDRAW file (this file) and creating a PDF based on the press default and native color only the very best RIPS in the world can handle it. In short a files like this published to PDF unflattened, needs A TRUE Adobe PDF based RIP that supports live transparency.
Third depending on the quality of your print shows RIP and their technician you may have to create a flattened version of the CorelDRAW file and output that to PDF.
David, Thank you for your response. I can see you have mastery over this subject from decades of posting on it.
It's confirmed what I suspected about the fall off in the Corel > PDF > printer process. I don't think the local printers here will be able to handle the file "unflattened" and flattening leads to definition loss.
I work with proof colours on and in CMYK for designs going to print to ensure a straight transfer.
1. If I wanted to produce an unflattened PDF for the printer RIP, what procedure can I use except the Corel "press default" and "Native colour"?
or
2. How does one accomplish a TRUE Adobe PDF based RIP that supports live transparency?
Cheers! Jim
Here we go, first take this as technical observation of the state of the technologies involved in the process based on nearly 50 years in graphics and over 30 years of digital output, no criticism is intended because the graphic application user in my opinion is in many instances and for decades has not been given the facts straight up so they can make intelligent choices. I tend to just say it as it is, and it has become worse now that I'm at a place in my life where I no longer have to work at all. I only work because I enjoy my work and always have.
The discussion is the technology to create, display and output art at the technical quality level of the piece you posted. Remember there IS NO PERFECT! Only as close as you can get within your ability to interpret the processes.
The display issue is multifaceted, it's much more than just using proof colors on, you do need to use proof colors turned on in Draw, but you also need the hardware, software and have the knowledge required to use them to have the best chance of designing, soft proofing, hard proofing and outputting as close to what you see as possible. Even then you have an error factor, you need to develop a (what you used to call) a relationship with the display and actual output.
There is no display under $1,000 in the U.S. capable of doing this properly, then you need to have a display profiling application and hardware, learn to use it and regularly calibrate it. That's another $300. Anything lees adds to the error factor.
Windows is an OS capable of allowing color management but the OS itself and the Windows applications are NOT color managed. Anything you see in Windows, the browser, email, Word, a PDF viewed in a browser will not look correct. You need to understand how to set Windows to allow color managed applications to function properly.
All of your graphic applications need to have their color management coordinated as much as possible, color engines, rendering intents and profiles. Adobe software has not been state of the art for a very long time, it lacks flexibility so in 99.9% of the cases you'll need to maneuver your other applications toward Adobe because of this. A PDF file for graphic output is intended to be viewed in Acrobat, however Acrobat requires that you set up the color profiles to match the file many times is does not view PDF files properly without doing so, in any case Acrobat display has shortcomings, it's just not a really accurate display.
The above is base technology, this discussion is about CMYK profiles. A CMYK profile is about limiting total ink and gray balance in a matter that you like. It matters what CMYK profile you use to create but it DOES NOT MATTER if you create in a CMYK profile that your printer (printing company) uses!
So, if your design is for newsprint use any newsprint CMYK profile that looks good, if the work is sheetfed uncoated use any CMYK uncoated prolife you like, same for web or sheetfed coated. I can explain this but it's another 15 to 20 paragraphs, just trust me.
Once you have all the above or if you decide that you're going to stick with what you can do without replacing hardware, WITH SOFT PROOFING turned on try different CMYK profiles and see the results of your FILE AND PDF. Remember to set Acrobat to the same CMYK profile used to create your test file. I find three CMYK profiles work well for me a very old Kodak UCR GCR 300 for uncoated and a Kodak UCR GCR 360 for coated and a GRACoL V2 coated 2006.
Now that you have all this information you have what you can do to create live transparency PDF files for a true PDF RIP except for this one teeny bit of information. Transparency ONLY EXISTS in a postscript/PDF environment as a raster. It can be a vector encapsulated bounding box but the transparency itself is always a rater. CorelDRAW calls them lenses. Corel and Adobe approach transparency in different ways so Corel and Adobe transparency can both output but not be edited across the applications. The same can be said about cross application editing for fountain filles, (gradients) in Adobe.
A RIP (Raster Image Processor) is a software and usually, (always in state-of-the-art systems) a hardware combination that actually interprets your PDF file and rasterizes (converts it to an image), in print work usually to a 3,200 DPI image. A true PDF RIP supports live transparency meaning that you do not have to flatten your transparent effects before creating the PDF and post rasterization software in the pre-press stage can edit the transparency as well as all other elements in the raster file.
You cannot accomplish a TRUE Adobe BASED PDF RIP, you must buy one or use a vender that has purchased one. Look at $75,000 and up as the base prices. That's why you see so many issues with transparency in PDF files. Well into the 99% range output professionals do not have a true PDF RIP.
CAVEATE: yes, you'll hear and read about users sending out files and they claim that all went well. That happens for two reasons, one the user has a process that does not allow them to actually see what they've created and two, 99.9999% of those files are simply rasterized by the output professional in a PDF application or an image editor that supports PDF into an image and the output professional places that raster into their file.
David, thank you. I feel so much better informed than I was 5 minutes ago even if I had to read it twice.
At this point I'll save my 75k USD for the dream boat and use the tech I have to harmonise my designs across apps. To check what you're saying in summary - If I were to export my design from coraldraw as a soft proof pdf (ISO Coatsed v2 (ECI) without rasterising or flattening the graphic elements (leaving all gradients and transparencies intact) and sent that whopping file to a printer (and ignore opening it in Adobe Acrobat or Afinity) would a printer of calibre (with the suitable RIP) be able to view it as designed?
Just create it in CMYK with proofing turned on, then export a press default native color PDF.
Finding a printer to do it may be tough, in the U.S. the quality of technicians at print shops has been in steady decline.
Make sure they have a PDFBRIP capable of outputting live transparency.
Thanks for your assistance on this. Everything you've said has been very useful and thought-provoking.
In the end if you find a great vendor the difference between your display and your print will depend about 85% on the quality of your display system.