Contax g filters for what use?

[Aquilasfx]

Hello,
I found to an old drawer 2 filters for my contax g2:
- L39 (UV) MC
- 1A MC

what is the difference, and do I have to use them for what?

I usually shoot in color and in b&w

 

[shimokita]

L39: High-quality UV filters are referred to as “Sharp Cut” filter because they begin absorbing over 90% of UV light to passing all visible light in the span of only 20-40 mn. UV filters are rated by where this 90% UV absorption is reached. L39 UV glass absorbs 90% of UV at 390nm and below while L41 UV glass absorbs 90% UV at 410nm. All high-quality filters absorb 98-100% or more of UV within 20nm below their L rating and pass 99% of the light within 20 above their L rating.

Wratten 1A: Called a skylight filter, this absorbs ultraviolet radiation, which reduces haze in outdoor landscape photography.