Exactly.
연(軟) means light, 진(津) means dark.
You need to add them in front of the basic color names.
You can also use 담 and 암.
담 is light and 암 is dark. They are not very often used, though.
As for 담 and 암, we usually don't say 담파랑 but 담청색 or 연파랑.
We usually don't say 담노랑 but 담황색 or 연노랑.
etc..
By the way, 섹 is incorrect. 색 is right word for color in Korean.