The black makes the colours stand out more boldly, giving the image a dynamic look, compared to the more natural white. I think both of them look good, and I believe both would appeal to different people, depending on if they would prefer a black or a white T shirt, since I know some people who would prefer one over the other.
Since I can put more than one T shirt on my mockup page for submission to their site, I will put both colours on to allow people to have an option if it were to be printed.
The details I applied to the top half of the shield make the piece look more finished; with the two lines connecting the gap in the red and green sections it creates a separation between the shield and colours. Now that I have applied all of the elements to the design, it was time for me to try out the design on a mockup T shirt!
|Finished black lines around shield|