Led Matrix 24x10

Hello,

I want to make a led matrix of 10 lines and 24 columns.
But i have a question about powering the leds.

I created a 5x5 matrix, but when 1 line of 5leds is on, the leds are dimmed

The lines are powered with a 74hc595 and the columns with another 74hc595 with on each output pin a resistor and NPN for the ground.

I don't want this problem in my 10x24 matrix.
what must i be used for powering up the matrix?

each led must have the full brightness (20mA)
i want to switch 480mA, but the 74HC595 connat and tpic6B595 is only sink.

who can help me?

my local parts shop say to use a 74LS595, but see no difference

What about a 4017 decade counter for sinking?

74HC595 controlling PNP transistors to source current into anodes, 74HC595 controlling ULN2803 to sink current from cathode columns.
200mA to sink per column.

Depending on the way you wire it up will depend on the software you need to multiplex it.
http://www.thebox.myzen.co.uk/Workshop/LED_Matrix.html