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Quick complement to explanations to let blurred2016 understand what he should do in practice.

 

Basically, we have:

1. a numeric representation of colours, that are those numbers in JPG, etc...
   
2. an objective reality of colours, which are specific electro-magnetic frequencies (or wavelengths), measurable with scientific instruments such as spectrometers;
   
3. a subjective perception of colours performed by our eyes and brain.
   

Point #2 and #3 are related, but we can simplify and drop #3. So all boils down to the way in which numbers at #1 are translated into specific radiation frequencies and vice-versa: the job of screen/printers and camera sensors. Each device (display, printer, camera sensor) behaves in a different way, so the same triple (e.g. RGB values 124,76,94) usually relate to different colours.

 

In a few words, with some imprecision but not so relevant: files produced by cameras contain a "colour space", which is a mathematical description of how to match a triple to the captured wavelength for that given sensor. A "colour profile", on the other hand, characterises a display device or a printer, and contains the mathematical description to compute the right power to drive a LED or the quantity of inks to mix to produce the correct wavelength than our eyes will interpret.

 

In order to correctly reproduce the colour through the chain "wavelength in the captured scene -> numbers in the file -> wavelength in the rendered scene (display/printer)" you need to have the right colour space and colour profile. In the consumer world, you don't have anything to do with the camera: the colour space is already provided and fine. But you don't have a proper colour profile for the screen or the printer (and the specific paper), so you should create it by yourself with a procedure called "calibration" and a few specific tools (the good ones for consumer aren't much expensive, in the order of 100€). Calibration implies also adjusting some settings on the device (e.g. the contrast, brightness etc... on a display).

 

Note that so far I've described a process for trying to get to the display and the printer with the closest perceptual match of the original colours. You mentioned different renderings of films and this has to do with personal taste. In the calibrated workflow I've described, this adjustment to your personal taste consists in changing numbers at point #1 with the sliders of a post-processing software. The workflow makes sure that what you're seeing on your monitor is seen also by other people on their monitors (assuming they did the calibration) and - roughly - the lab you're sending the photos will print stuff that mostly matches what you see on your monitor.

 

Do you really need a calibrated workflow? If you're going to share large numbers of photos (e.g. publishing them on the web, or having a printer lab to do your prints), yes, you do. Tweaking single colours is a waste of time, really. Better spending a few money and a few time to have calibration working properly and, after learning the job, everything becomes simpler and faster.

 

If on the other hand you don't share pictures and you just print by yourself a few ones, then you're probably fine by tweaking colours individually, starting from the ones you care much.