Nominal Thickness Data (mils)

• 2462, 2468, and 2470: 4.0 mils Estar base (4.2 mils total, unprocessed)
• 3468: 2.5 mils Estar base (2.7 mils total, unprocessed)
• 4462, 4468: 7.0 mils Estar base (7.2 mils total, unprocessed)

Exposure

The following data indicates meter setting values for 1/25 second tungsten exposures calculated using the formula 45/H, where H is the exposure in lux-seconds required for a density of .20 (1.20 for  x462 Microfilms) above minimum density with indicated processing. This number can be used directly with incident-light meters.

• x462: 2.1
• x468: 0.2
• 2470: 0.12