if using clear substrate then reverse print clear applied to back side and laminate it with white translucent...But if you double strike the ink the colors will be dark during the day and correct when lit, or if you don't double strike the ink it will look good when not lit and washed out when lit....
if using white/translucent substrate then forward print clear vinyl and laminate with a good laminate (i.e. oracal 3651 clear laminated with oraguard 215) and apply to front side...but you will still have the light/dark issues depending on if you double strike the ink or not...
solution is to apply the laminated/clear print to the face of the white/translucent and don't double strike the ink...then print the same design in reverse and apply it to the back side (I laminate the back side for ease of install but might not be as necessary on the back)...don't double strike the ink on either print. The end result is that the color looks correct when lit or not. And because the two prints are separated by substrate (white diffuser) you don't have to worry about lining up the two prints exactly. If you are within 1/8" or less then the line up looks good since the light is diffused after it passes through the back side anyway. I've done this many times on acrylic and polycarb and have signs out there that are 5+ years old and look like the day they were printed. Very important to use a good laminate on the print of the front surface that is your primary protection against UV.
You can do the same process with UV direct print but I typically avoid because you will still have to laminate the front surface or it won't last. I have a UV printer but haven't had a lot of success direct printing for this application...it works but not ideal and is less durable and really doesn't save a lot of time/money over applying vinyl (for this application). And you would still need to worry about getting a good line up and not scratching the print during transport/install. UV prints scratch more easily than laminated vinyl prints. Just my 2 pennies