PLease help ! - brown to red

i dyed my hair for the first time a few weeks ago . My natural color is a really dark brown with natural red highlights in the summer. I wanted to bring out the red tint so i dyed it brown-red. Im in a cosmetology program at my high school so i used to dye in school not a store bought boxed dye. I wasnt satisfied with the results and i want more red. I figured since the brown is dominant , thats why the red wont take. Now my hair is brown but you can see the red clearly in the sun. I want to re dye it but not use any brown this time. However , i want to keep my dark hair and i dont want the red to be too bright. My question is , if i put just straight red dye over the color i have now will it blend with the brown or come out bright red?

I'm not sure that I will be much help, but I do know that red dye can be VERY hard to get out once its in.  I went from blonde to auburn last fall and going back to blonde was very hard!  I had to go to a salon to get it done cause nothing I did worked.  Just be very careful.  Baby steps may be a good thing. =)  Good luck!

My hair was virgin and the red is already fading . I had someone suggest highlights but i really wanted just one color . i'm gonna try the highlights tho , thanks !