The same combination, as B/W photo's are made up from many shades of gray. The separate black cartridge you can purchase is for a mix of text and colour graphics, or text only.
You will notice a big difference in the quality of black text if you use the correct cartridge.
But for all normal printing even for colour photo's I use the black and the colour combination with excellent results. Only remove the black and replace with the photo colour for top quality photo printing were the use of six colours makes a difference.