Photek use the American MIL Spec technique based on the USAF test pattern (1951) to measure limiting image intensifier resolution. The limiting resolution steps on this pattern are large, 20, 23, 25, 28, 32, 36, 40 lp/mm and the limiting resolution is quoted as the mean value achieved in two orthogonal directions. Because the pattern consists of only three short bar pattern in each direction, the result is not particularly favourable to Photek compared to the other techniques described above.

Limiting resolution is dominated by MCP pore/pitch as shown below:

Tube Size	MCP Pore Size	Typical Limiting Resolution with P43 Phosphor *
18 mm, 25 mm	6/8	40 lp/mm
40 mm	10/12	26-36 lp/mm
75 mm, 150 mm	25/32	10-15 lp/mm

These values are quite consistent with the MCP. For example, with 12 micron pitch, there are 80 MCP pores per mm, corresponding to 40 lp/mm if the test pattern is perfectly aligned with the MCP. Since it has a hexagonal structure, it is impossible to align it in two directions at 90° to each other.

High gain tubes are most commonly used in photon counting systems. The superior pulse height distribution is used to discriminate between photon events and electronic noise and the resolution performance can be recovered by suitable event-processing software. Photon counting systems can in fact achieve resolution only limited by the size of the microchannel plate pores (usually 10 microns).

* Phosphor particle size does effect resolution and should be considered.