[Enhanced Senses/*-Tech] Illumination Levels and Flashlight Beams

[Celti]

Enhanced Senses provides us with a very detailed table of illumination levels, with two entries for flashlights (one “standard”, one "high-quality") and a clear rule on how the illumination penalty for those flashlights decreases with distance.High-Tech and Ultra-Tech gives us a variety of flashlights, each rated with a "beam length".

I spent quite some time trying to reconcile these two systems, until I re-discovered a rule in Campaigns that I had forgotten long ago, due to the damage it does to nearly any combat-heavy game in dark environments (which fact I would prefer not to debate, given that it is not the point of this post, and the other things discussed in it solve the problem):

Originally Posted by Campaigns, p. 394

A torch or flashlight reduces the
penalty to attack rolls for darkness.
Assume that any such light within line
of sight reduces the penalty from -10
(total darkness) to -3. Almost every
light source has a limited range or
radius – see the item description for
details.

With that rule remembered, applying a -3 to the illumination level of High-Tech's “flashlight” and “mini-flashlight” gets numbers that respectively match the “high-quality flashlight” and “standard flashlight” entries in Enhanced Senses.

Thence comes a handy rule of thumb for converting an “illumination range” as used in most GURPS supplements to the illumination levels used in Enhanced Senses: Find the range penalty for the beam length, and reading it as a bonus, cut it in half and subtract two; e.g., the 10-yard range of a basic flashlight is a range of -4 — reading that as +4, halving it, and subtracting two gives +0; while the 100-yard beam of a large tactical light is a range of -10, which becomes an illumination of +3 (which, by the associated rules for being dazzled, will require HT rolls from anyone currently adapted to twilight or dimmer — which seems quite spot-on to me!).