If I upload a RGB profile, will the proof have pretty accurate colors to what will be printed?
All jobs are converted to CMYK before printing, and sometimes the conversion from RGB to CMYK can cause a color shift, but it is not on all colors. It is not possible to know until the conversion is done. In addition, the monitor's calibration can change how a color looks, and we have no way of knowing how someone's monitor is calibrated. If colors are important, we suggest to ordering a hard copy color proof.