PDF CMYK Problem

[Newbietoo]

Thanks Jimi

The prints are pretty straightforward at this stage e.g. Business Cards, without bit maps. When it gets more complicated we may well move to a different printer.

I think what I'm learning here (and I'm not a neophyte in computer graphics, but I am when it comes to printing CMYK) is that it's an even more inexact science than printing usually is, as we're dealing standards for incomparable mediums that have no direct cross-relationship.

I'm figuring that if the printed output looks right and that it is quite different to what the PDF looks like on screen, then the CMYK information is in the PDF file and that I'm likely to get the same result if I send that PDF file to the printer

A different, but related question. If I can print RGB from my CMYK printer and it near enough matches the RGB on screen, why can't professional printers do that?

Thanks
Patrick

[jwhitham]

Thanks Jimi
A different, but related question. If I can print RGB from my CMYK printer and it near enough matches the RGB on screen, why can't professional printers do that?

Thanks
Patrick

Coz they need to be able to suck their teeth, exchange amused glances, blow out their cheeks and say 'well, that's going to cost you'.

[alanstancliff]

It might be worth your while to see what happens in a couple of non-Adobe pdf readers.

As sledger says, a lot of people prefer FoxIt. When my boss needed a freebie reader because the Adobe product was screwing up, I found that the reader from VeryPDF was the best for his needs.

One would think that Adobe apps would be the best for handling pdfs. Sometimes they are, but in many, many cases, they aren't. In tests I ran over several years, the Jaws Editor usually did a better job displaying pdfs and often when printing them. My service bureau routinely chose Jaws pdfs over Acrobat when I gave them a choice.

I haven't compared Jaws Editor 4 and Acro 8 (the current versions) because I'm currently running an Adobe-free machine, and we have no need to upgrade Acro.

I recently installed the Adobe Reader 8 (the latest version) on my Windows XP-2 computer. That was a big mistake. What a resource hog! It constantly tried to "phone home" to see if there were any updates, and in so doing, it took up 100% of my resources, making my computer completely unusable. To rid myself of this troublesome priest, I had to boot into safe mode.

After I installed Foxit reader, I wrote Adobe an email explaining to them that I did not get my computer so it could do nothing but check to see if I had the latest Adobe reader. Sheesh!

[steve.ledger]

http://www.talkgraphics.com/attachme...1&d=1208905002

Of course you realise that this is no comparison at all.
Unless you have a perfectly calibrated monitor profile AND the correct paper for your home Pixma printer and ink combination.
Inks ain't inks and paper ain't paper

[Jimi King]

If I can print RGB from my CMYK printer and it near enough matches the RGB on screen, why can't professional printers do that?

Thanks
Patrick

Our domestic/office printers are trying to emulate the professional process, not the other way round.

Your PC printer deposits all the colours in one pass. A professional bureau makes four separate passes (Cyan, Magenta, Yellow & Black) to arrive at the final print.

Many printers are now doing digital printing which I believe is similar to the single pass method, but they are primarily designed to make smaller runs and larger sizes easier & financially viable. They're not the same as, or generally as good as the four colour (or in some cases six colour) process.

Actually, for the record, your colour 5FBC47 is not RGB. It's the hexidecimal reference for RGB as used by web browsers. Xara very kindly gives you both. The RGB reference is represented by three values (Red, Green And Blue) shown as percentages.

And like Sledger says, that colour is meaningless. Look at it on six different monitors and you'll likely see six different colours.

BTW, you might find this great little free widget useful.

http://www.nattyware.com/pixie.html

[Tao jones]

very handy indeed jim..thanks tao

BTW, you might find this great little free widget useful.

http://www.nattyware.com/pixie.html

[Charles Moir]

A different, but related question. If I can print RGB from my CMYK printer and it near enough matches the RGB on screen, why can't professional printers do that?

It's my experience that modern inkjet printers have extended the color gamut (i.e. the range of possible colors) considerably over the last 5 years or so, way beyond what traditional CMYK commercial printers can achieve, and I think that's part of the answer.

Having said that no printers is ever going to produce true fluorescent colours as you can get on screen. Take 100% pure RGB green. This really is ultra-bright fluorescent colour that is way outside the range of any printer I know. And ultimately that's the source of the whole problem - you can see a much wider range of colors on screen than the printer. Hence the whole complex process of converting RGB to CMYK colours is needed. And although there is a lot of science behind it all, the process and knowledge required to really understand is huge. This is part of the reasons we do not offer these advanced CMYK facilities in the entry level Xara Xtreme - because it is a complex area.

It's also known that traditional printer's CMYK inks are pretty poor - certainly they are not the pure CMY colors they should be. Were they accurate then the K (black) component would not be necessary. As it is if you print 100% CMY, the theory is this should be pure black, but in practice is a rather muddy brown. And so this is partly why K was added, and the software has to go through a hugely complex processes called grey component replacement and undercolor removal, to convert RGB colors to CMYK. There are myriad different ways to do this, and this is what the ICC Pre-press profile manages - each of those profiles is a slightly different equation for converting RGB to CMYK, which has slightly different color weighting and conversion rules.

The Xara 'Simulate Printer Color' option is there to convert the screen colors to more accurately reflect what you see on a printer. It doesn't help that Adobe do things a slightly different way around. They (in Adobe Reader for example), show CMYK colors always in 'simulate print colors' fashion and always show RGB colors as bright screen colors, even though that is not an accurate reflection of how they will print. The Xara 'simulate print colors' approach is simpler in that we just show all colors on screen (RGB or CMYK) in the printer gamut. This explains why the same color in RGB and CMYK appears quite different in Adobe software, whereas they are shown the same in Xara (that is bright in screen mode, dull in 'simulate print color' mode).

A basic set of guidelines, that should always produce reliable results, is this:

1. Switch 'Simulate Print Colors' option on to get a better idea of how your colors will look printed. (This is not 100% accurate, but no system is. It's a rough guide only, but certainly better than 'Screen Color' mode)
2. Generally we recommend using RGB (or HSV - which is just another type of RGB) colors for all normal purposes (photos from Digital Cameras are all RGB, and and it's better not to use other software to convert these to CMYK)
3. Use specific CMYK values only when you have a very specific CMYK color to be reproduced. e.g. a specific Pantone color. Avoid CMYK colors if you at all can.
4. Do not mix transparency with CMYK colors. i.e. if you put transparent shapes over CMYK colored objects, even feathered shapes, or shadowed objects, then the CMYK values underneath are messed with and will not reproduce accurately. So a basic rule: do not mix transparency and CMYK colors. Always use RGB (or HSV) colors when using anything that involves transparency. This will produce more reliable results.
5. When sending PDFs to commercial printers, always select the 'Commercial Printing' PDF/X option, and preview the results in Adobe Reader.
6. For larger commercial print jobs always get a wet proof, i.e. a real printed example from your printer for checking.

If you follow these guidelines then you should get very good results all the time. We, and we know many customers, regularly produce high-quality, large print run commercial brochures, leaflets or posters. We know Xara can produce results as good as anything Adobe can, and usually a whole lot easier, certainly quicker, and usually you do not need to understand any, well much, CMYK science.

Ooops, sorry for the long post.

[MEB]

Thank you for the LONG post, Charles. I really appreciate all the explanations you gave. It´s hard to get a global "consistent" view of what´s going on specially with subjects like this one, regarding the use of Xtreme.

Trying to get the handle of all this from diferent sources with diferent experiences usually only complicate things more.

This is (at least for me) the most "obscured" area (print, colors) when working with xtreme. Not because the software isn´t able to do it, but because i have not found yet a clear idea/workflow of how to get reliable results when mixing images coming from diferent proveniences (with diferent color spaces), with and without ICC´s, with vectors all in the same project without screwing up something.

I dont´know what i should worry about first! How the icc´s embeded in images interfere with the work in xtreme, if i should retouch the images in photoshop first before importing them to Xara (that will display them diferently showing diferent retouched/colours at least on screen), etc.

I don´t want to even talk about joining acrobat to the party to preview the results...

But i have to get there, and this thread looks a good way to start messing with all this stuff...

[Newbietoo]

Yes thank you Charles...I fear I have unleashed a monster with this topic

I have been doing more research as some of you have suggested and succeeded in plumbing ever greater depths of confusion

Where this all started was that I had thought, naively it seems, that given I have a CMYK Printer I could produce a reasonable facsimile of what a "Professional" printer will produce with his CMYK Printer. Just select CMYK colours in Xara...export to PDF, then print, and Bob's your uncle. BUT...

Apparently there is compensation upon compensation happening here e.g. my Canon Printer (or at least the driver) is doing its best to emulate RGB, notwithstanding I have applied CMYK colours to my images. That is perhaps because the average punter expects his printer to print what he sees on his screen...silly person . Only joking!

I did find in some forum where you can get specialist drivers e.g for Epson printers at circa $300+ (this is a just driver mind you not a printer) to get them to print CMYK.

So perhaps there is no way, other than getting a wet print as Charles suggests, of being sure what the eventual colour will be. Unfortunately this is only feasible with larger jobs. With business cards they aren't interested

Thanks again folks for all your help. And yes, that little "Natty" thingy Jim is handy.

Patrick

[Jimi King]

I don't think the options of ordering from Brisbane would be too attractive price wise given that these guys are in the UK, but they are the printers I use for all my stuff.

http://www.rcs.plc.uk/

They are very good and they'll do a wet proof on anything as far as I can see (however it practically doubles the cost of a set of business cards).