RGB to CMYK??!!!

[gohard]

Hello Folks,
I am experiencing major difficulties when converting RGB LW renders to CMYK in Photoshop CS2 for print. They are images of golf course holes, which are obviously greens and blues... these are the colors that lose their values the most. My bright greens go to olive and so on...
Anyone have a solution to this problem?
Muchly appreciated,
-Adam

 

[cgolchert]

Hello Folks,
I am experiencing major difficulties when converting RGB LW renders to CMYK in Photoshop CS2 for print. They are images of golf course holes, which are obviously greens and blues... these are the colors that lose their values the most. My bright greens go to olive and so on...
Anyone have a solution to this problem?
Muchly appreciated,
-Adam

Are you going to print it yourself? If not ask if they can accept a RGB file. Most higher end print software can accept both. RGB will maintain nicer colors until it hits the ink system.

 

[Crocodilian]

out of gamut

The correct way to deal with this is with a calibrated monitor in Photoshop, with the correct profile for your output printer loaded. RGB to CMYK conversion should be done in Photoshop, not LW . . .Photoshop has more and better tools for dealing with this not-easy issue.

This is not a casual retouch problem, . . .my recommendation would be to ship the file to the service bureau and let them do the conversion.

 

[awrieger]

The coloured area is L.A.B. colour, which is basically every colour the human eye can see and given a coordinate number by an international consortium in Paris back in 1936 based on its relative position in the area (just like latitude and longtitude on a map). These coordinates are used in all modern colour management systems and profiles.

The white area overlaying it in the middle represents the full coverage of CMYK printable colours.

The black triangles are two electronic colour gamuts/profiles. The three points of these triangles are the famous R G and B - red, green and blue.

The smaller triangle is the sRGB profile which is the standard for monitors and hence electronic graphics like the internet etc. But unfortunately as you have found out trying to print golfing greens, it is useless to you if you want to print greens or sky blues because as you can see, if you convert a file in photoshop to the sRGB colour profile, you clip off and lose the printable CMYK blues and greens which lie outside the sRGB gamut.

The Adobe profile on the other hand covers the printable CMYK colour range so you should always have Photoshop set to that one if you are aiming to keep rich greens and sky blues intact to print in CMYK.

 

[wacom]

It's worth the time and money to have someone calibrate your monitor to your printer if you know which printer(s) you'll be using. If you're shocked at going from RGB to CMYK, don't forget that things are going to change once it's printed too. There is probably someone in your area who will create a profile for around $50. Well worth it in the end.

 

[Silkrooster]

You can also buy spyder 2 a device to calibrate the monitor. I beleive they now have a bundled version that includes software or something to handle the printer. Not sure on the printer part as I only quick read it over.
Both pcconnection and provantage carry the product.
Silk

 

[ackees]

Make sure you have an apple LCD, I have found the output to print from the view on these pretty good, and they come with ColorSync profiles built in.
(if you have the money for the profiles stuff then go for it)

Pre plan your colours, make sure the colours you pick when constructing your scene are CMYK, then make them RGB for less problems back to CMYK later.

Find out what profile your printer is using and set your photoshop to match theirs.

 

[Darttman]

Prints are reflected light and monitors are emitted light. Here you have two basic differing types of color. Now as for accuracy of color on monitors, a good old CRT is much better for proofing and calibrating than an LCD.

You must create color profiles for all the hardware you use and then calibrate the monitor to all of your system (including software.) On a PC this is called the ICC or color profile which all hardware has.
If you are sending it out to be printed you must then contact the service bureau and ask them for some help/suggestions on the color tweaking as they would be dealing with your file. There are so many variables you will run into when trying to proof your own work on a printer such as lighting conditions, paper type, and of course all the calibrations on the hardware/software you are using.

Bottom line work with the service bureau who will be printing or working with the printer you will use.

Good luck

 

[fabmedia]

Hello Folks,
I am experiencing major difficulties when converting RGB LW renders to CMYK in Photoshop CS2 for print. They are images of golf course holes, which are obviously greens and blues... these are the colors that lose their values the most. My bright greens go to olive and so on...
Anyone have a solution to this problem?
Muchly appreciated,
-Adam

It's quite common for new commers to print to have unknown results (unexpected that is). First of all, what OS are you using? Have you calibrated your monitor? Have you set up photoshop for sheet-fed workspace?

There are a huge list of things that you can experience with RGB to CMYK. First of all, the colour spectrum of RGB is far bigger than CMYK. The main thing that you'll notice is that RGB images have a tendancy to be over saturated. Most of the time you'll notice this in extreme blues, and mostly in yellows and oranges. It can be a pain in the ***, but if Photoshop is set up properly, your monitor calibrated @ 6500K (it will change your monitor to a yellowish tint and simulate the colour of paper), you will only notice a slight change if any to your image. Monitor callibration is extremely important when creating for print. I have my monitor callibrated for my whole workflow, LW, video, photoshop, etc. That way, I know what I'm getting across the board and the colours that I see in one app are going to be pretty close to another. I have over 10 yearts experience with print so if you have any questions, PMB me directly.

Good luck.

 

[starbase1]

On this subject, as there are clearly some experts, I'd like to ask a dumb question...

I have produced satisfactory conversions to CMYK before now, and as we all know the shift in some colours is very marked. And yet when I use my home printer it manages fine printing directly from brightly coloured images. My last printer did this too, so I don't think its particularly new technology.

Are home printers really better than the big ones the pros use? Or am I missing something fundamental?

I'm specifically thinking of a CD cover - the customer wanted me to use an image with some bright violet in it. Looked fine on my printer, but the CMYK conversion really neutered it.

Nick

 

[fabmedia]

@ starbase 1

Most consumer printers are built to reproduce colours that are on your screen. Most of the them now have additional exceptionally brighter colours to help reproduce highly saturated colours. This allows for a more WYSIWYG for RGB images. Some press printers use a Hexichrome print process that uses a similar technology to preproduce a larger spectrum of colour which uses additional colours beyond the typical CMYK process.

If you correctly set up your monitor, you should be able to see correctly RGB in a CMYK spectrum. That doens't mean that your colours won't be out of the spectrum, but if you convert your image to a CMYK format, you should notice very little difference, if any at all after the conversion. Mainly the problem areas are highly saturated blues, yellows, and oranges. Sometimes it's hard to explain, but if you do colour correct your system properly, then you will have no problems once you convert your image. One of the best ways to preview your image in Photoshop is to do a "soft proof" of your image before conversion. It took me a while before I understood the whole process, but once you get it your set. Just remember, you need to calibrate your monitor on a regular basis to make sure that you are seeing the colours as closely as possible. Your monitor should have a yellow tinge. I use a gamma of 1.8, and a target white point of 6500° K. Some people go as low as 5000° K which makes the display really yellow. The target white point is used simulate the brightness of paper. Hope this helps.

 

[Matt]

To add, bluey greens, blues and purples are the worst colours to match screen to print (or scan for that matter).

As suggested ANY form of calibration will acheive better results, no matter how little, use none and you leave any control up to the programs you're using.

If you have Photoshop CS2, you can also render your images in 32bit (high Dynamic Range - HDR) which will preserve many more colours.

In a nutshell preserve the quality of all images for print until the last minute (going to print) and then have as much calibration as you can be bothered to implement!

 

[fabmedia]

Yes, do not convert your image back and forth because you will lose colour values. Use the soft proof option. This will give you a good approximation of how it will look when converted to CMYK.

ONE LAST THING... you don't need someone to calibrate your monitor, you can do it yourself. IF you are on OS X, the monitor preferences has everything you need to calibrate your monitor, on the PC, use the software supplied by Adobe. You don't need any special machine to calibrate your monitor. Don't let anyone else tell you otherwise. It's a huge waste of money.