Hi,
A question I have is the following: Are you driving the LEDS/the 2N2222s via the Arduino with a signal like a or a signal like b?
View attachment 152943
I guess/hope you mean like b due to the huge reduction in heat and savings in unnecessary power use (260mA/4 = 65mA average over time, or e.g. 3V * 65mA = 195mW/LED as opposed to 780mW/LED...2N2222s - I doubt they want to endure 780mW as they are more like roughly 600mW max., from memory) and as we know, slow human eyes/POV is important to consider...
So what's your driving signal like, then, please?