Resistance is a derived unit. It is not possible to have a resistance value without calculation, it can only be "derived" using volts and amps.

This ^^^^

Someone has to do the calculation...

Anyway, as it seems like a game, one more "method" is to use the voltage ratio operation of a multimeter. As the voltages on two resistors, connected in series (same current), is proportional to their values so is also the ratio of them.

Connect a reference resistor R

_{REF} in series with the lamp R

_{lamp}.

Connect a variable voltage source to the series combination.

Connect the reference input (V

_{REF}, usually the "sense" input) of the meter to the R

_{REF} and the input (V

_{IN}) to the R

_{lamp} (Ask from someone to read the manual and to tell you how to do this!).

Adjust the voltage to the brightness you like and measure the ratio. If the R

_{REF} is equal to one Ohm, the ratio is Ohms of R

_{lamp}; if it is one kilo Ohm then the ratio is R

_{lamp} in kilo Ohms.

You can stick a piece of paper to the right of the last digit of the display with an omega symbol (or 'k' omega) to avoid confusion ...!

Of course this does not work with zero volt or outside of the instrument capabilities.

In this method the indication is "resistance" but we are measuring voltages, so it is indirect...

If a direct resistance measurement is needed, the only method that I can think is someone to go inside the material and examine the paths of possible electricity routes!!!