I agree with some of the comments made by eegirlee. I think the background's contrast is too low. I didn't notice the crosses at all until I read her crit. In general it is a good idea to have the background have less contrast to create atmospheric perspective and depth, but i think in this case, there isn't enough contrast between the red and black for the cross. Part of this could be due to your monitor's settings. On your monitor, it may be clear as day that the crosses are separate from the background, but on everyone elses it's different. look into calibrating your monitor.
You guessed just right - crosses look neat on my iMac and rather good when printed. I checked other computers too and saw the background almost black...