Profiles!

[johan]

HI,

I am new to this site, so my question might sound very simple to some of you?

This has been an question that I get various answers from and not all the same.
If you get a tagged/untagged document and you are printing to a rip and KM6500 for example how do you know when/what is best profile to use. Do you leave the file always in RGB(if you need to send it to someone for more printing) or you convert to CMYK. Can you convert to your output profile and what would happen if you set your output profile in the RIP and you convert your file (Photoshop) to an output profile of the KM6500,does it convert twice?
If you simulate an environment/proofing or need to send the file to an image setter do you leave it in RGB or do you still convert to CMYK.
What is difference between CMYK mode and converting to a CMYK profile in Photoshop?

I have asked many users/specialists but everyone has got an different opinion

Hope someone can help with this one

Regards,

Johan

 

[mattf]

Wrong section of the forum, but anyway....

Multiple questions here and I will try to answer them as simply as I can.

As having designer/pre-press experience in the past I always ask customers to convert files into CMYK before they send files to us. That way the customer has some expectation of the color change from RGB to CMYK. If we do it they get mad, so having them do it and tweek the color as they feel fit will help us in the tail end to produce it faster.

Technically yes, if you have two profiles and you use both on the file one after another the color will change. Knowing what color profile the printer is using will be helpful in order to understand and better prepare your files for the printer.

Most print shops have the same color profile at the RIP that they use in Pre-press, so as long as you know that profile you can have better expectancy of what color your going to get.

There are multiple CMYK modes. You can have multiple types within photoshop to convert the color to a specific profile. Understanding your RIP and what profile pre-press is using will help to prevent as much variability from occuring throughout the pre-production process.

 

[Lukas Engqvist]

It is best to allways tagg. Usually what happens is that the user is unsure of colour management ans turns it off, this stripps profiles.
I would say untagged profiles in RGB should be sRGB since the www is the only place that would possibly justify untagged RGB data. Also non ICC compliant applications usually assume sRGB.
Untagged CMYK is usually safe to assume either that the colour purity is higher precidence than colour accuracy. I would assume that coulour in such cases is the regional standard for coated (or the default profile you get in Adobe suite).
CMYK is device specific wich is why it is a great idea to use a PDFx standart wich has output intent! Colour will be managed, for a given value of managed.
I would not convert colour in Photoshop, better to do it in Acrobat 9 since then you can handle images and graphics the same way. Normally I convert colours using convert to output intent and give the new output intent, that way it is clear to the next person down the line what my intent is.

 

[smatros]

Can anyone recommend any good inks on this topic - like a guide to pre-press color management or color management for digital printers. I would like to enhance my knowledge and resolve some issues I am facing with files.

 

[claude72]

What is difference between CMYK mode and converting to a CMYK profile in Photoshop?

• switching from RGB mode to CMYK mode just using the "CMYK mode" command in Photoshop always converts the picture with the profile selected in your working space
(or the Photoshop's default profile if you did not change it)

• using the "Convert to a CMYK profile" allows you to choose another profile, (normally) different of your working space profile.
For example, if you are normally working with a SWOP coated profile and you want to exceptionally convert only one picture for uncoated paper, you can simply "Convert to a CMYK profile" choosing a "SWOP uncoated" profile...

(and if you "Convert to a CMYK profile" choosing the same profile that is selected in your working space, you will do the same conversion than with the "CMYK mode" command)

Do you leave the file always in RGB(if you need to send it to someone for more printing) or you convert to CMYK.

Always keep in your mind that as soon as you convert a picture from RGB to CMYK, you convert it to a printable color mode with a specific printing profile... and the printing profile will make in the picture all the needed corrections to allow this picture to be printed in a specific printing way: mainly dot-gain and GCR/UCR corrections to adapt the picture to the paper, to the inks and to the press...

... and if you use an unadapted profile, like a coated profile for an uncoated paper, or a sheet-fed press profile for a web-press, or an american profile for a european printer, or a CTP profile for film outputing, you will get unexpected results!!!