Is there a science to picking the colors that work well together in a design, or is it just subjective?

Definitely there is, it’s the colors harmony, and there are many theories for harmony the most 3 mains is: - A color scheme based on analogous colors - A color scheme based on complementary colors - A color scheme based on nature and your main guide is the colors wheel, plus your artist sense for sure.

Hi Reem Boudraa, Thank you for Inviting me to Answer this Question.
I believe both of them (Science versus Subjective) are inter-linked with each other.
Something like “Husband versus Wife”, “Brother versus Sister”, “Day versus Night” and “Good versus Bad”.
The Color is a Commanding tool in Graphic Design.
It can be used to Attract Attention, Classify Content, Highlight Elements or Evoke Emotions which would help a Design look Aesthetically Pleasing.
To choose the Precise Colors and Color Combinations, it is Important that the Graphic Designer should have a Fundamental Perceptive of Color Theory.
There is NO Universal Color kind of recipe that will Delight all Types of Clients and Employers.
Through proper Research, Sense of Style and Good Common Sense, Designers can eliminate the long process of experimentation.
White Light is a combination of all the Colors of the Spectrum which is Divided into Red, Blue and Yellow.
From these 3 Colors, Designers can combine every Colors Imaginable to Human Eye.
A Designer should know what the Company and Their Products are about to have a Head Start on picking the Colors.
Color is a good way to catch the Eye of Viewers, but too much of Color might Distract your Readers from looking closer and reading on.
Color Combinations should be created through Careful Research and Study.
By knowing the basics of Colors and Shades, Designers can create several Aesthetically Pleasing Color Combinations.
Hi Ghady El Hajj, Thanks for posting this Topic.
Indeed mesmerizing subject!

There is definitely a science.
However, there are usually many correct options, so there is also a subjective element too, which is what makes design so awesome.
Different designs call for different colors and styles, however, in all good designs there are always a few common denominators ...
for more Info please read this helpful page: http://curaqion.com/issue/01/science-in-picking-colors-for-design

i think both of them(Science & Subjective) are important.

Sometimes, but better to be your reality Style.

It is a matter of vision, idea,talent through which an artist or architect depict into paper or monitor.

 

Of course there is a science of color consistency and compatibility between light and dark colors, luminous and gloomy colors. These rules differs per design. However, there are some main rules that cannot be neglected, including that writing text color should be a contrasting color from the background color completely, and lack of industrial light effects on a light background.