The most recent SWTOR game update 7.1 brought the ability to customise your own dialogue/subtitle text colours, size, transparency and background shadow colour. You have full RGB access to changing both the text and the background shadow to anything you want or helps you see better.

To customise your subtitles, start by clicking the little + sign on your primary hotbar, or by going to the settings button on the gamebar and clicking the tab “Interface Editor”.

From here a large editor box will appear, in the dropdown menu under the words “Global Scale” select the catergory Conversation to specifically see only the locations of Dialogue boxes in the game (arrow 1).
Then click the ‘Conversation Subtitles’ bar (arrow 2), this is the container that allows you to edit the settings for subtitles/dialogue in the game.
From here you can then use the large editor box‘s bottom catergory (arrow 3) to enable or disable cutscene dialogue, as well as the following changes:
Scale: The size of the chat font.
Alpha: The visibility of text (100% = visible, 0% = invisible).
Alpha Background: The visibility of background shadow fade (100% = visible, 0% = invisible).
Subtitle Color: The colour of the subtitles themselves, opens an RGB window to select colour wanted (arrow 4)
Background Color: The colour of the shadow behind text to make text stand out better against cutscene details (arrow 4)

Once you have made the changes you want, click the little save icon before closing or hitting escape to exit the Interface Editor.


Thanks to Emi’thiss for getting me the images on short notice.