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Computers and Software => Raster and Vector Manipulation Programs, and How to Do Stuff in Them. => Topic started by: Prosperi-Tees on March 07, 2012, 11:34:49 PM

Title: RGB to CMYK conversion for business card printing.
Post by: Prosperi-Tees on March 07, 2012, 11:34:49 PM
So I got a job for about 6K business cards. They send me what they designed and its in RGB. I know I can convert it to CMYK but on screen it looks alot different than the RGB version. The printer that prints the cards want the files in CMYK. Is this conversion from RGB to CMYK going to be as dramatic of a change when it goes to print as it looks on screen?
Title: Re: RGB to CMYK conversion for business card printing.
Post by: Screened Gear on March 07, 2012, 11:46:24 PM
Short answer: no
Title: Re: RGB to CMYK conversion for business card printing.
Post by: Prosperi-Tees on March 07, 2012, 11:56:12 PM
I guess I could verify somewhat by printing it out on my printer in both the cmyk mode and the rgb mode huh? Sometimes its the easy solutions that escape you! lol.
Title: Re: RGB to CMYK conversion for business card printing.
Post by: Screened Gear on March 08, 2012, 12:35:26 AM
I guess I could verify somewhat by printing it out on my printer in both the cmyk mode and the rgb mode huh? Sometimes its the easy solutions that escape you! lol.

RGB is what you see on a monitor. CMYK is how the paper is printed. They are two different systems. Printing it out on your ink jet (unless color calibrated) would show something completely different then you would get sending it to a offset printer. Most printers now days have a rip (or preflight software) that converts all RGB files to CMYK (to many people forget to convert them.) If you’re worried about colors on the design you can always select them with the eye drop tool in Photoshop and then double click on the color it selected in your tools panel and it will show you the pantone color that is closest to that color. If you have a pantone to CMYK pantone book you can then get a good idea of what that color will print when sent to a offset printer. Its not a exact but it is close.
Title: Re: RGB to CMYK conversion for business card printing.
Post by: Prosperi-Tees on March 08, 2012, 12:39:19 AM
Thanks I will give that a shot.
Title: Re: RGB to CMYK conversion for business card printing.
Post by: Denis Kolar on March 08, 2012, 08:07:30 AM
You should not have any issues with the conversion. Also, you could do some optimizing, color correction, but for that you would need to have better monitor that will show you what exactly are you changing.
You could go in each channel and check the threshold levels and than later adjust it in levels panel. That way you could change color ranges and make your image color to "pop" a bit more.
Title: Re: RGB to CMYK conversion for business card printing.
Post by: Dottonedan on March 08, 2012, 11:53:58 AM
I'm going to toss this out as well. YES, it will change GREATLY depending on the art. You say it's RGB. This is what the artist or designer has made and many that are not familiar with printing process think that it should come out looking like it does on screen. Since 90-95% of my cohorts that I used to work with (about 50 artist) were not experienced at printing in any field, they most often expected the print results to look more like they see on screen.


Someone mentioned that some printers convert the RGB files automatically to CMYK.  I say, that ALL do this, as they would HAVE TO. None (no color printer) that I am aware of, prints in just RGB colors. Some print in CMYK + RGB or + BG or + light K and light pink etc. but none in just RGB so it has no other choice. They were kind of saying that but I took it a step further.


As stated, monitors show art in RGB and you can preview files in CMYK conversion (but this is still viewing that conversion on screen (in an RGB monitor). The only way to see how it will really print in CMYK is to print it out in CMYK (on a CMYK off set press) because even digital printers don't actually print out in just CMYK.


Back to the art. Art created in RGB with vibrant magenta's. neon's, fluorescence purples and greens, are extremely difficult to convert to CMYK. These vibrant files NEVER convert accurately. It's like trying to match a PMS color using CMYK inks on press for tee shirts. very difficult. PMS colors are inks that are specifically mixed and some PMS colors can't come out right in CMYK tee shirt printing or even off set printing.  These vibrant images fall outside the color gamut of what can be printed in CMYK. You can still print the file, but it will most likely be dull compared to the RGB file. It's just life. Most people (who are not familiar with the print process) are very disappointed in the results and think the conversion looks dim and dirty.

Title: Re: RGB to CMYK conversion for business card printing.
Post by: Prosperi-Tees on March 08, 2012, 12:27:18 PM
It looks like a blue on screen, im just hoping it does not come out to some wierd shade of purple or something
Title: Re: RGB to CMYK conversion for business card printing.
Post by: shellyky on March 08, 2012, 12:33:00 PM
It looks like a blue on screen, im just hoping it does not come out to some wierd shade of purple or something
i bet it comes out slightly purple...that is a weird shade to print CMYK....light blues (unless almost cyan) will almost always take on a purple tone...print it off on your color printer to get any sort of an idea on what it will actually look like if I were you.
Title: Re: RGB to CMYK conversion for business card printing.
Post by: Prosperi-Tees on March 08, 2012, 12:37:01 PM
I just printed it on my epson office printer and 2 options it gave me adobe rgb and epson vivid. The rgb comes out brighter and the epson vivid comes out lighter and more purpley.
Title: Re: RGB to CMYK conversion for business card printing.
Post by: Denis Kolar on March 08, 2012, 12:39:27 PM
Yep, you might want to cut back a bit on magenta in the background.
Title: Re: RGB to CMYK conversion for business card printing.
Post by: Colin on March 08, 2012, 01:12:06 PM
Shelly has it right.

Change the blue to a more pure Cyan shade, taking out as much magenta as you can get away with... and then some.

Then you want to make sure the grey you have in that door is a true nuetral grey, otherwise it will come out with a color shift.

Wish I didn't have to say the above is from personal experiences.... but it is :( 

Good Luck!
Title: Re: RGB to CMYK conversion for business card printing.
Post by: Prosperi-Tees on March 08, 2012, 01:17:10 PM
C-41 M-11 Y-2 K-6 is where it is on screen. All these numbers are getting to me now.
Title: Re: RGB to CMYK conversion for business card printing.
Post by: Sbrem on March 08, 2012, 01:53:03 PM
Also, understand that RGB is what you can see, as it's white light (the combination of all colors of light = white) Ink is not light, therefore, CMY was derived, and black added after that, for printing purposes. CMYK cannot produce all the colors you can actually see, but does a great job making full color images. For instance, no combination of CMYK can make a fluorescent color, you need to use fluorescent ink. Cyan, magenta and yellow are each derived by subtracting one or the other of RGB, eg. subtract the Green, and that leaves you with Red and Blue, making Magenta. RGB minus Red, leaves Green and Blue, making Cyan. Lastly, and this one's a little weird, RGB minus Blue, leave Red and Green, making Yellow. (I didn't invent this, just reporting). So, theoretically, 100% of each Cyan, Yellow and Magenta creates Black, but it doesn't quite work, so Black was deemed necessary in the darkest parts of an image. This not the most in depth explanatiion, but is the crux of it anyway.

Steve
Title: Re: RGB to CMYK conversion for business card printing.
Post by: Chadwick on March 08, 2012, 06:42:01 PM
Everything said above.
and,
If you're designing for offset ( CMYK ) printing, use the CMYK spectrum ( the screen approximations ).
Title: Re: RGB to CMYK conversion for business card printing.
Post by: Fluid on March 09, 2012, 08:13:46 AM
When you convert from RGB to cmyk as mentioned above you will most likely need to do some color correcting. Your best and safest bet is to convert that image to a CMYK bitmap and publish / print the file to a PDF. Make sure your PDF settings preserve the CMYK image and send that to your client for proofing purposes. 

As many have mentioned your monitor will show RGB and most programs will give you a gamut preview of colors when converted to cmyk.  If your monitor is NOT calibrated correctly guarantee your colors will be off no matter what. If your printers is not calibrated correctly with your software and monitor your are even more off color wise. 



Title: Re: RGB to CMYK conversion for business card printing.
Post by: Prosperi-Tees on March 09, 2012, 11:56:28 AM
Ok WTH did I do wrong? Now when I go to export it does not export the text, just the blue background.
Title: Re: RGB to CMYK conversion for business card printing.
Post by: Fluid on March 09, 2012, 01:04:18 PM
make sure your layers are not locked if you are using layers.
Title: Re: RGB to CMYK conversion for business card printing.
Post by: Prosperi-Tees on March 09, 2012, 01:16:12 PM
i got it, it was actually the first one in the 6 pages I had. The first one was a copy/paste from MS Word.
Title: Re: RGB to CMYK conversion for business card printing.
Post by: Sbrem on March 09, 2012, 04:17:02 PM
Ah Word, the undisputed king of graphics software