How to convert RGB to CMYK

Because we print your artwork using CMYK colours rather than the RGB used by computer screens, it's best practice to convert your project to CMYK before sending it to us. This way you can adjust any colour shift that may occur.

Converting RGB to CMYK

When creating your artwork, it is best to set up your file using CMYK settings. In apps like Adobe InDesign and Illustrator, this means selecting the ‘Print’ option when creating your file initially and converting images and creating colours in CMYK as you work.

In some circumstances you may need to work in RGB (for example you want to use certain filters in Photoshop, certain colours in Illustrator, or are saving files for web as well as print), or you may be working with artwork you have been sent. In those instances here is our best practice guide to converting RGB to CMYK.

To accurately convert your document follow these steps:

  1. Select ‘Edit’ > ‘Convert To Profile’.
  2. You will see two options under ‘Destination Space’. Leave the ‘RGB Profile’ as is, but change the ‘CMYK Profile’ to ‘Coated GRACoL 2006 (ISO 12647-2:2004)’ - this is Mixam’s preferred CMYK profile.
  3. Go to the ‘Conversion Options’ and select ‘Adobe (ACE)’ as your conversion engine. Choose ‘Relative Colorimetric’ for your ‘Intent’. (Choosing this preserves all RGB colours that can be accurately used in CMYK. It will also automatically replace any colours that cannot be replicated in CMYK with an appropriate equivalent.)
  4. Click ‘OK’.

Convert colour profile in Photoshop

While it may be tempting to simply select ‘convert to CMYK’ options in your app, this is not always the most accurate method. There are a number of different CMYK colour profiles available and it is important that you select the right one to match your printer’s chosen profile.

Adjusting CMYK values

While the majority of colours will convert from RGB to CMYK with no problem, if you notice any obvious colour shifts when converting your project, then you may need to take a step backwards and adjust some of your values before converting.

If you are converting swatches in InDesign or Illustrator and see a small preview with a yellow warning triangle underneath a colour, that means it cannot be accurately replicated. Clicking on the warning triangle will convert the colour to print safe values, but make sure you are happy with the change.

When converting artwork or images in Photoshop, you can check your colours before converting by going to View > Proof Colours. This will display the image in your apps’ chosen CMYK colour space without permanently changing the colour values. From there you can adjust levels, contrast, and saturation in order to get a satisfactory colour balance before you convert.

Once you’re happy with everything, then you can convert your file using the technique above. You can now export your artwork to PDF knowing that you are happy with the colours you have used.

Choosing colours in Adobe creative tools

Exporting CMYK files to PDF

When exporting your artwork to PDF, Adobe applications offer a variety of presets. This is our quick guide to exporting in InDesign, Illustrator, and Photoshop. (Other apps may offer similar functionality)

Exporting via Adobe InDesign

Once you have finished your artwork checks in Adobe InDesign, go to File > Export. In the Save Destination panel make sure to select Adobe PDF (Print) option in the Format drop down. In the Export Adobe PDF panel, select ‘Press Quality’ which will provide you with the majority of settings we require. For more information, you can read our full guide to exporting a PDF here.

While the default colour settings in ‘Print Quality’ cover most of our needs, we do recommend that under the Output section, you make sure that ‘Colour Conversion’ is set to ‘No Colour Conversion’ and the ‘Profile Inclusion Policy’ is set as ‘Don’t Include Profiles’. If you have not set everything up exactly as we require, this will avoid conflicting information being included in the PDF.

Select 'Press Quality' in Photoshop

Choose 'No colour conversion' and 'Don't include profiles' in Photoshop

Exporting via Adobe Illustrator

Unlike InDesign, there is no option to Export as a PDF in Adobe Illustrator. Instead you need to select File > Save As and then save a copy as a PDF. You will encounter the same PDF creation panel as in InDesign; use the same settings mentioned in the section above. When saving, make sure to select ‘Save As A Copy’ or else you can lose any unsaved work.

Save as Adobe PDF in Photoshop

Adobe Photoshop also uses a ‘Save As’ technique for creating a PDF. Go to File > Save As and select Photoshop PDF from the Format drop down menu. it is also best to select Save As A Copy here to avoid losing any unsaved work.

TIP: If you are exporting artwork for us on a regular basis, you can set up a Print Preset and label it ‘Mixam’ in order to make sure you have the same colour settings for every export.

Automated RGB to CMYK

If you are unsure of the best way to convert your work to CMYK or do not have access to Adobe programs, we can help.

When you upload RGB colour files to your order, our system will automatically and intelligently convert the colour values from RGB to CMYK for you.

If precise colour accuracy isn’t an issue for you, this is a very quick and easy solution! But please check your electronic proof before confirming you order, so that you can see what your colours look like after being converted.

Print proofing checks

The downside of allowing our system to do the conversion for you is that you are giving up some control over how your project will turn out. In addition, our team is not able to change any colours after the conversion.

So, if you want your project to accurately reflect your vision, we recommend that you take your time to follow the steps above, to convert your colours from RGB to CMYK, and fine tune them to your liking before uploading your artwork. And please always check your electronic proofs.

Example of an RGB image
RGB image
Example of the same image set to CMYK
CMYK image
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