HI Expertise am having a problem in Publishing PDF. In my Corel draw X6 there is two images one is hand and another one is pack shot of syrup so the problem is in Coreldraw the image resolution was high but when i publishing to PDF the pack shot image resolution was too low and jagged edges. At the same time the another hand image is fine.we are using PDFX1A standard PDF settings. attached file for reference.
Thanks in Advance.
draw the image resolution was high but when i publishing to PDF the pack shot image resolution was too low and jagged edges. At the same time the another hand image is fine.we are using PDFX1A standard PDF settings. attached file for reference.
https://www.dropbox.com/s/pz3zxofdd5fw8my/x-3%20acrobat%208.zip?dl=0
Here are the pdf files results with your attached photo , X1-a and x3/acrobat 8.
Is the hand picures above or below compared to box/bottle picture and the hand picture transparent side obscures the box/bottle picture ?
If the hand picture is above compared to box/bottle picture and the transparent side is obscure the box/bottle picture , try x-3/acrobat 8 . Some pdf settings from corel not support transparency.
Another option: covert in one bitmap with white background all pictures and publish to pdfx1-a or x-3/acrobat 8.
Looking at your file, there are several things going on here.
Most obvious is that the X1-a preset by default downsamples images to 300dpi. The difference is hardly noticeable with the hand, but the small text in the bottles photo is not going to survive that very well. You can see the exact effect this will have by selecting the photo on its own in the CDR file and doing bitmaps > resample > 300dpi. Comparing with the 1100 dpi of the original, the difference will be instantly noticeable and zooming in close will show that 300dpi just does not have enough pixels to render small text well.
It is possible to over-ride the downsampling, by going to the settings button in the PDF screen. But a quick test shows no improvement in the resulting PDF. I think this is probably because the bottles image is a transparent image, which the PDF spec does not allow. CorelDraw must therefore merge the image with its background to comply with the X1-a.
To output this at higher resolution, you therefore need to do two things:
This will give you some improvement, but you may need to increase them both to 1200 to use the full resolution of the photo.
harryLondon said:Most obvious is that the X1-a preset by default downsamples images to 300dpi.
Yes, that's the only problem.
harryLondon said: To output this at higher resolution, you therefore need to do two things: In tools > options > document > page size, increase the rendering resolution to 600dpi In the PDF screen, go to settings and in the objects tab increase the bitmap downsampling for colour to 600dpi. This will give you some improvement, but you may need to increase them both to 1200 to use the full resolution of the photo.
First of all, we should think why Adobe put a limit of 300 dpi for their "High Resolution" PDF presets (such as PDF X/1a, PDF X/3, etc). The image resolution is relative to the quality of the output. If the file is sent to an imagestter or CTP at 150 lines per inch, the max quality available will be 300 dpi (150x2) On the present, most CTP will output up to 175 /200 lines per inch (LPI) so the max quality available is 400 dpi (200x2). No matter if you send a 600 dpi image, 1200 dpi or 2400 dpi, the output has a physical limit, then will never output at more than 400 dpi (usually 300/350 dpi). Sending a PDF with 1200 dpi images only produces bigger files, but it doesn't increase the real quality. Although you send a 1200 dpi image, it will output at 300 or 350 dpi. And no more, since it's enough for the best quality printing.
Of course, if you open the image on your computer you will see better at high resolution, and if you convert to 300 dpi the image quality looks very bad. Don't worry, the result will be good.
SO, if you want you can change setting when publish as PDF, and send images with more than 300 dpi, but keep on mind that the only difference will be on your screen. The file will be printed at 300 dpi anyway