As for showing anything online, my distorted thinking says you can calibrate your screen perfectly, but if others are viewing your images on uncalibrated screens, it might be a waste of time.
This is my thinking, I've ntrol ever printed anything myself and can count on the fingers of one hand the number of digital photos I've ever had printed. I know screen calibration would mean what I was seeing would be correct, but 99.9% of people viewing the images would be on an uncalibrated device (almost certainly a phone or tablet these days) so what's the point?
IMO it is impossible to mitigate for the huge variation of potential viewing environments of others viewing online!
After having a photobook printed years ago, that came back too dark, thankfully just a couple of them, I got a calibration device. I could have gone back to the printer and said the images were too dark, but they would have just asked if the monitor was calibrated, and the answer would have been no. I couldn't very well blame them for a mistake if I were not giving them accurate files.
That was because, by default the monitor was too bright, and I compensated by darkening the images to make them look 'correct' to me. Most calibrators will probably say lower the brightness of the monitor, at least the two I have had did/does. The also has the benefit of not blasting your eyes with too bright a light, which can quickly become tiring. I calibrated, re-edited, re-uploaded, and all perfect printed.
My way of thinking is, if I get things accurate for brightness and colours, that is all I can do. Yes, I have no control on the myriad of devices out there that may see the images, but they are all mostly aiming for accuracy, and then maybe a bit oversaturated and bright for tablets and phones especially. I get things how I want them to be.
There are some devices that can monitor the ambient light in real time and compensate. I think my one can do that, but I don't need to. I most always edit after dark, with the curtains closed, in the same position, and so in a pretty consistent environment. I calibrated at least once a month, because monitors degrade over time, which you may not notice. I also calibrate my cameras for accuracy of colours, and consistancy between cameras.
The OP may want to consider a calibrator, as once the thought is in the mind, is what I am seeing 'right', either for brightness, colours, or both, the easiest way to banish the thought is a calbration device. But people can do as much or as little as they want to.
