18" AFF

[suntint]

Floors can be terribly un level. Better to start somewhere at whatever height is specified AFF and then keep the bottom of the film running straight and level and not depending on the height above what may be an un level floor. Could also measure down from the top of the glass frame and keep that measurement the same since the top of the frame usually runs straight and level.

[kats2112]

Like I said, specified this time. It happens. I usually do the pencil mark thing with a rod or channel.

Doing anything from the top down was clearly out of the question for obvious reasons.