CPC - Howto

Sunday, September 7, 2008

Convert RGB to CMYK with Adobe Photoshop

To accomplish this procedure use Adobe Photoshop 4.0 or higher (recommended).

	1.	Launch the Adobe Photoshop (screen capture show Adobe Photoshop 7.0 menus). Open the image that needs conversion from one color mode (RGB for example) to CMYK mode.

	2.	Before doing any conversions, check your existing Color Settings by going to the Photoshop File menu: CMYK Setup... (Versions 5.0, 5.5 and 6.0) If you are using Adobe Photoshop 7.0 go to Photoshop->Color Settings..


		If you are using a version of Adobe Photoshop earlier than 6.0, use the following setting for your Color Settings... CMYK Setup: Choose Built-in for CMYK Model Choose SWOP(Coated) for Ink Colors Choose Standard 20% for Dot Gain Choose UCR for Separation Type Set Black Ink Limit to 85% Set Total Ink Limit to 320%
	3.	In the Photoshop View Menu->Gamut Warning The Gamut Warning option allows you to see which colors will be difficult to reproduce when the image is converted to CMYK. Potential problem colors will be identified by viewing the image changes: Colors in the actual image will be indicated with a specific color (you can edit this color in the Transparency & Gamut preferences panel). If your image has any color that will be reproduce poorly, be sure to edit the image by adjusting the color curves or changing the saturation, contrast, or brightness, before converting to CMYK.

	4.	Go to the Photoshop Image menu->Mode->CMYK If any of the colors in the image were outside the gamut of CMYK colors you will see a shift in saturation. Ensure these areas of color still represent your intended message. Editing the image may be necessary. You can adjust the curves or adjust the saturation, contrast, or brightness until you are satisfied. Doing these modifications in CMYK mode is optimal.

	5.	Finish by saving your image as a TIFF file. Click here to see instructions.