Not Clear, Readable ???? But How
If you have done your FP on FP Scanner (Computer, Imager, what ever you want to call. You can actually see what is happening. That is when they keep your finger on the Scanner Area, your impression will appear on the monitor and a message appears, as PASS(as Green) if the Print is Clear and RIDGE BREAKS(as Red) if the Print is not clear.
This Process is repeated until all the Fingers PASS.
If You have done in Manually (That is the Thumb Impression as was done in St.Louis 1 & Half Years back), then the chances of (Not Clear, Not Readable, etc....) can become.