When you export a file to PDF for prepress the CYMK values do not stay correct. Try a spot color and check values in Corel, export to PDF prepress. Open in Photoshop or Paint and check values. They are no longer correct!! This works fine in X4 and makes X5 pretty useless for commercial printing.
good stuff happening here!.. i will offer a question though - Gennedy, you're arguing the case for BPC very clearly, yet BPC is not an option in CorelDRAW. are we to assume BPC will be added next time or even in an update?
the issue at hand is that Relative Colorimetric rendering of bitmaps does not produce very good results at all for shadows or darks. it will create flat black fields of color where there should be, for example, dark hair with highlights and noticeable texture. in the meantime Perceptual is the only CorelDRAW alternative.
Hi Ghiangelo,
I hope we will be able to add BPC in Draw, however first we have to make sure that whatever we come up with works well. Definitely maybe.
At the moment there are only 2 ways to bring BPC into X5, and the second one is purely hypothetical: 1) download and install Adobe CMM 1.1, select it as active color engine in Default Color Management settings dialog in X5. You can turn BPC on/off in Adobe CMM via their XML configuration file, details are in AdobeCMM Read Me.pdf file installed at C:\Program Files (x86)\Adobe\Adobe Utilities\Adobe CMM
2) Microsoft WCS has black point preservation mechanism built-in, however apparently it will work only in pure WCS color conversion ( both source and target color profiles should be WCS XML-based ones ). Which are non existent at the moment, which makes this path unrealistic.
Gennady
First let me say that this s a great discussion and thatmy only complaint is that BPC breaks with the ICC rules. Now with that said I wil point this out and then will place some image up in future posts.
A large gamut like Prophoto is at least 70% bigger than any CMYK considering a fixed pixel, so when using BPC 70% of the pixels color is significantly changed while 30% is left unchanged. This IMO causes in some cases issues, it's like a 500LB person lsing 300 LBS in a year. Sure they're thinner but their skin is still too big so they look odd. An od way to explain it but there is no one way nor one correct to compress a large gamut to a small gamut.
Ok I have put about 30megs up on my FTP site, these are files handled as perceptual rendering and WCS and also as relative colorimetric with BPC onand the Adobe CMM.
If you're serious about this conversation e-mal me at davidmilisock@graphictechnology.com I'll send instructions.
Hi David,
OK, lets do it. I will contact you via email to get these test images and see what you are talking about.