Interesting note from an Ayurveda class I did recently,
All the 3 doshas in our body – Vaat, Pitta, Kapha – have 5 sub-types each. One of the sub-doshas of Pitta is Ranjaka.
Ranjaka Pitta is what gives the human blood – it’s color, which is red. “Ranj” comes from the word Rang or color. This color is only one of the outcomes of Ranjaka pitta’s function – which is to take the output of digested food and convert it into vibrance and energy in our system.
Thus, very clearly at the micro-functioning level of the body, the Red color and Vibrance in our body is connected. I haven’t delved too deep into Ranjaka’s working. But I found it interesting because,
I have earlier come across this relation between red and vibrancy from Sadhguru when he spoke of the Devi,
“In the tradition, Devi has always been red, since red is the most vibrant color – and feminine represents that. Devi spaces always have very active involvement of red in many ways.” (Source)
Knowing about a fundamental connection of our red blood color and vitality/vibrance in our body was very interesting. I am yet to understand this better but wanted to share with you all. 
I was suggested by someone to have things around me representing different elements (air, water, earth, fire etc.). In it, they said succulents & fountains help with the water element. For air, windows should be kept open i.e. enough ventilation, and for fire,
vibrant colours such as orange, yellow and red were suggested!
I already had many plants / soil for earth. Quite naturally, around that time, I was also drawn to those vibrant colours and had ended up purchasing flowering plants in shades of orange & yellow.
Somehow, I am not as much attracted to red as I am to other colours which are considered as fiery.. But yes, colours do seem to play a role in our moods and how we think. Fiery or vibrant colours are known to fuel creativity..
This was a nice post to read as I always wondered about kumkum being red too!!
Hmm. When I started the akhand diya, I was also thinking about having some interactions with all elements, the way I was having with fire.
But I haven’t explored much of that … But for Fire I feel a lamp is much direct interaction, than opting for any color shades.
Also, in this blog post I am only highlighting an interesting mechanism within the body that directly connects the red of the blood to our vibrancy.
I as yet am not connecting any major influence to simply having red color around us. It’s true , for a lot of people these fiery shades spurts creativity… But I think other cooling shades can be equally relevant.
Red color is used in Devi sadhana a lot , I am yet to ponder on its influence and what exactly is happening there.
Also, about kumkum being red – I think it is more about its properties as anti bacterial , anti inflammatory and all that, for which it is being used so prominently?
There are too many nuances about the usage of kumkum including one of social signals.