As a scientist, what do you need to know about terms like RGB, CMYK, 300 dpi?

Navigating the world of scientific publishing? Understanding terms like RGB, CMYK, and 300 DPI is crucial for a seamless submission process. Here's a quick guide for researchers!

RGB vs. CMYK: RGB stands for Red Green Blue. It is a colour model commonly used for screens (TV, monitors, digital cameras). CMYK stands for Cyan, Magenta, Yellow, and Key (black). It is a subtractive colour model used for printed work (e.g. paper version of scientific journals or printed posters, etc.).

300 DPI: DPI stands for Dots Per Inch. It refers to the resolution or clarity of an image, specifically in printing. 300 DPI is the minimum resolution for sharp images. Ensure your graphics meet this standard for optimal clarity.

Making charts: When making charts, I would recommend you to start making your graph in RGB/300DPI. The RGB colour mode is ideal for presentation slides and 300 DPI guarantees a good quality. When you need your chart to be printed (e.g. on a poster), you can convert it to CMYK using tools like Adobe Photoshop or Illustrator. Ensure that the logo of your institution or company is in CMYK format as well when incorporating it into your poster.

Submission process: When you are submitting your article to a scientific journal, you need to check the author guidelines on the requested colour model. Some scientific journals request RGB, others CMYK images. The majority of journals will require a resolution of 300 DPI. Be aware that journals might also export their PDF’s in CMYK, which can result in minor colour changes in the online article.

Check Your Colours: When converting from RGB to CMYK, minor colour changes are typical. Usually they do not affect your image. However, more noticeable shifts can occur with bright and vibrant colours. These shifts may lead to undesired changes when working with similar hues. An example is given in the image below. The colours in the top row of the chart are easily distinguishable in RGB but become less so in CMYK. In the bottom row, the colours remain relatively unaffected by the conversion from RGB to CMYK. As such, always check for unintended colour shifts, particularly among similar hues. The same accounts for conversions from CMYK to RGB.

To preview colour changes quickly, utilise tools like Adobe Illustrator or Photoshop. Ensure that "View >> Proof Setup >> Monitor RGB" is selected, representing the colours on your screen. Then switch to "View >> Proof Setup >> Working CMYK" to preview how the colours will appear when printed.

In conclusion, it is crucial to maintain substantial contrast between colours to prevent a confusing chart. To ensure visibility in both RGB and CMYK colour models, opt for colours with similar brightness levels and preferably varying hues.