Response time of a norp12 cell

I have a project comming up where I want to use a vintage indicator, I intend to remove the incandescent bulb and fit an led, but what I also want to do is put a ldr in the lampholder with the led, then switch the led off and measure the ambient light level with the ldr, then switch the led on again.
How long approx is it going to take for the ldr to change resistance from being dazzled by the led to giving a realistic resistance dpending on the ambient light?
I'd like to see if it can be done without noticing a flicker.

Probably not, but with no part numbers it is impossible to say or find out. What you can do is look at the voltage across the LDR at turn-off. There should be a rapid but measurable exponential increase. In general, an LDR is the slowest of all light sensors. Phototransistors are much faster, and photodiodes the fastest.

ak

Assuming you mean ORP12?, then they are relatively slow devices, usually considered too slow to be used for sending audio over a light beam - but for your application, give it a try and see.

I thought the orp was obsolete, the little ones being norp12, spose they are the same electrically.
I found a datasheet, if you can call it that, change to light is fairly quick, change to dark is really slow 120ms, the 'sheet doesnt say if thats from min reistance to max resistance, probably is.
I'm thinking of writing some code that makes multiple readings and accepts when the reading has been stable for a period, obviously with a getout to prevent hangups.