CMYK and RGB
What Is CMYK Color?
CMYK (Cyan, Magenta, Yellow, Black) is the subtractive process colors that are used in color printing, out of which black (K) is used to enhance color and contrast. The K stands for Key, which is the color that the cyan, magenta and yellow lock to. Subtractive colors are used when mixing or printing inks as well as dyes and pigments. These colors work with reflected light and are suitable for printing on white paper and other substrates.
What Is RGB Color?
RGB (Red, Green, and Blue) are the primary additive colors that are used in display devices and scanners. These colors work with emitted light and are used to create the spectrum starting with a black background.
The Difference Between CMYK and RGB
Both CMYK and RGB are color models enabling us to see objects or scenes in varying colors. Human sight is based on RGB. RGB has a wider range of colors, known as a gamut, available. CMYK is used to replicate, as far as possible, anything created in RGB. CMYK has limitations as it has a smaller gamut than RGB. This means in practice that some colors are easier to reproduce in CMYK than others. Pantone special colors are used to print colors that are harder to match in CMYK. However, with full-color images, it is very difficult to see any difference.
A color image can be separated into CMYK components that are combined using the inks on an offset litho press. A modern offset litho press using fine screening will produce excellent results for images.
As a general rule, RGB is used for anything designed to be viewed on a screen and CMYK is used for anything reproduced on a substrate such as paper.
RGB – CMYK Conversion
Modern RIPs that process PDF files for printing have conversion software built-in that will change RGB to CMYK. However, it is good practice when creating artwork for print to convert artwork to CMYK early in the process. Digital, scanned and library images will all be supplied as RGB as the files are smaller and the color space larger. These can be opened manually in editing software such as Adobe Photoshop and then converted. Images can also be batch processed. Converting images can flatten the colors to a degree. This means you can alter settings to improve the image once converted. As a rule, the default settings on Photoshop work well for most purposes.
If creating spot colors or using the Pantone library for process colors, make sure you are working in CMYK. This will give the closest results on the screen to the printed jobs. Color charts are available showing all the different combinations of CMYK printing to make various solid colors.
The color breakdown of clients’ logos is particularly important. If they are going to be produced in CMYK then ideally they should be supplied to the designer in that format. A straight conversion from CMYK to RGB of a vector logo doesn’t always work that well when printed.
If setting up artwork from scratch, such as with InDesign, ensure the Document Color Mode is set to CMYK beforehand. Then import all the elements already converted to CMYK. Finally, create all-new elements as CMYK.
How to Change Mixed CMYK and RGB to All CMYK?
When creating a pdf for printing, the file can be set to convert to CMYK.
This will automatically adjust the elements but you will have less control over the final result. This is useful for larger jobs and if you have no control over the elements supplied. It also means you can export the files for both print and screen from the same original document.
The final files will also be converted to CMYK at the printers anyway.
A proof will show up any major issues.
Here Are Few Tips That Can Help You with Your CMYK Printing File
- If your artwork design calls for a rich black background, avoid using 100% black and instead go for C40 M40 B100.
- In order to save your photos from appearing darker after printing, make sure you convert all RGB color layout photos into CMYK before the embedding process.
- Avoid designing small text with CMYK color layout and instead, use just black.
- Make sure to convert your artwork to high-resolution CMYK artwork, once you are done with your layout and have converted it to printing artwork.
How Well Will My Photos Match What I see on My Monitor?
There are many factors that will influence how closely printed photos match a monitor. Monitors have different calibrations and color spaces as well as resolution settings. Therefore an image will vary from monitor to monitor for a start. A big factor is a paper used and the lighting conditions the print is viewed under.
Printers have closely controlled lighting conditions in order to guarantee the quality of color reproduction. However, viewing a print under different conditions makes a vast difference. Light is measured by color temperature and there are is a wide range of viewing conditions the effects this.
Natural daylight, office lights, and other sources all vary in intensity and warmth. A printed image will look totally different under these varying conditions.
A good printing company will work under set lighting conditions to produce the job to the highest standard.