To understand why it is so important, let’s return to the days when only film cameras existed, and the idea of Photoshop wasn’t yet realized. So, while shooting on color slide film, which many professionals and hobbyists used, the final images could not be edited, and it was impossible to change the colors of the photo. The color negative film offered more possibilities. However, it could not be compared with what one can do with modern Raw-files or scanned film.  

At that time the film you have chosen predetermined the colors of the final shot. For example, many landscape photographers used Velvia from Fuji because of its small-scale grain, high contrast, and saturated colors. But the colors of Velvia were not good enough for portrait shooting, so the photographers preferred to use a film that rendered colors more accurately and was designed to reproduce even the slightest shades of skin. It was necessary to learn how to choose the right film so as to get high-quality images. Thus many photographers explored a bunch of variants until the right option was found. 

Early digital cameras have a very simple color control. As a result, all the photos looked alike. One could try to change the settings, but they were too tricky and complicated. Then the manufacturers began to equip their cameras with color profiles and software so that a photographer could make some adjustments.

Camera profiles

Each manufacturer has a different name:

• Canon: Picture Style 
• Nikon: Picture Control 
• Sony: Creative Style 
• Pentax: Custom Image 
• Olympus: Picture Mode 
• Sigma: Color Mode 
• Fujifilm: Film Simulation 

The Image styles available on Canon EOS are Standard, Landscape, Portrait, Faithful, Neutral and Monochrome. The purpose of the most of them is quite clear. Other manufacturers use some variants of these names and sometimes add some of their own options.

While editing a Raw file in Lightroom, the program allows choosing a profile in  Camera Calibration. The top variant in menu – Adobe Standard, a profile created by Adobe especially for your camera based on thorough testing using color targets. The idea is that the same images, captured by various cameras will look the same when using Adobe Standard settings (assuming that other color settings such as White Balance, are also the same). 

In the early versions of Lightroom, Adobe Standard was the only profile and perhaps this can explain why a Camera calibration panel is placed at the bottom. Now in the menu, all color profiles of your camera should appear (however black and white modes may not be displayed). They are created in Adobe to simulate the effect of color profile and JPEG format on your camera.

How to choose a profile and processing methods in Develop module

So what will be the difference in post processing if you choose different profiles? You can see it once you compare two variants of one image, made on EOS 5D Mark III. On the fist image, a profile  Camera Standard is chosen in Lightroom. On Canon cameras, such profile provides saturated red colors and high contrast. The result is a bright, saturated photo.

The other variant is made using a  Camera Faithful profile, developed for accurate color transfer. Red colors are not so saturated, and the texture can be seen more clearly. This profile allows to process a photo differently, and it looks more natural, and the textures are more emphasized. One Raw file and two various approaches and two completely different results – and the color profile play a key role here.

Film Simulation profile from Fujifilm

Film Simulation profile imitates various types of film. The result differs greatly from what we get on Canon: each variant is more refined and has its own characteristics, so a photographer has to explore to choose the most appropriate variant. This brings us to the origins of color profiles.  

Some settings are so good that you want to use them constantly. It's easy to yield to temptation and use only one or two favorite profiles, neglecting an opportunity to use something else and thus limiting yourself only to 1-2 ways of processing. Velvia and Classic Chrome were particularly tempting.   

Here is a comparison of these two profiles. The only difference between two images is the various color profiles.  Velvia gives strong saturated color and high contrast as an original film. Classic Chrome weakens colors and provides less contrast, to look more like old slide films.

And this is the same photo processed with Astia and Adobe Standard profiles.  As you can see Astia gives the more natural look with more dimmed colors compared to Adobe Standard. 

In short, before you start to process a file in Lightroom, go to the camera calibration and select a profile. This will affect color and contrast, so do this before starting to work in the Basic panel.