Wednesday or Thursday has more Biblical support than Friday as the day of the crucifixion. The idea of a Friday crucifixion has been popular in large part due to a misunderstanding of the Gospel accounts that the cross followed by the Sabbath. Many mistakenly assume that is the weekly Sabbath which is Friday sunset to Saturday sunset, but this week there were two Sabbaths, the second being the "High Sabbath" of the Passover day. 

If you investigate, you'll find that the calculations for dates and days that far back are very complicated and there are different conclusions about it. Jesus died on the cross at 3:00pm and it was either Wednesday or Thursday. A Wednesday crucifixion gives three full days and nights in the grave: Wed, Thu, Fri nights and Thu, Fri, Sat days, then a resurrection at or after sunset on Saturday, which is considered Sunday. If it was Thursday, then you have Thu, Fri, Sat nights and Fri, Sat, Sun days, with a Sunday morning resurrection. That way, you have three full nights but just two full days and partial days on Thursday/Sunday.

There's an interesting book on the subject called "The Coming Prince" by Sir Robert Anderson (1841-1918) which calculates how the dates of Jesus' entry into Jerusalem that year exactly fulfilled Daniel's prophecy about the Messiah.