  The observation of spatial quantum noise reduction, or spatial squeezing,
with a large number of photons can lead to a significant advantage in quantum
imaging and quantum metrology due to the scaling of the signal-to-noise ratio
with the number of photons. Here we present a systematic study of the limiting
factors that play a role on the measurement of spatial squeezing with an
electron-multiplying charge coupled device (EMCCD) camera in the limit of
bright quantum states of light generated with a four-wave mixing process in an
atomic vapor cell. We detect a total number of photons per beam of the order
10$^8$ in 1 $\mu$s pulses, which corresponds to a photon flux per beam of the
order of 10$^{14}$ photons per second. We then investigate the role of
different parameters, such as cell temperature, pump power, laser detunings,
scattered pump background noise, and timing sequences for the image acquisition
with the EMCCD camera, on the level of spatial squeezing. We identify critical
parameters to obtain an optimum squeezing level and demonstrate that for bright
beams it is essential to acquire images at a rate fast enough to overcome the
effect of classical technical noise.
