Nikkor Lens filters

[jon.oman]

I have the following threaded Nikkor filters (round 52mm diameter).

They are labeled on the rim as follows:

A12
B2
B12
X0
X1

Can anyone tell me what the standard Wratten numbers are?

I lost the data sheets long ago!

Here is a sample:

[Keith Pitman]

Here you go. . .

[jon.oman]

Here you go. . .

Okay, thanks! That is exactly what I need.

[Drew Wiley]

There are some distinct discrepancies there, because the chart is showing both old obsolete Wratten numbers and a few current ones. These are just approximations anyway, and not necessarily identical, For instance, X0 is slightly lighter and less green than a Wratten 11 yellow-green, which on the comparsion chart is shown as X1 somewhat ambiguously. Variations between different manufacturers are common. I wonder if Nikon in more recent times made their own filters or subcontracted them to Hoya? - they are very similar, and so is Marumi. Nikon's red is equivalent to Wratten 25. Any of the later Wratten handbooks will show a far greater number of options than that chart; but there are no letter designated K or X filters, etc - all have actual numbers, with sometimes a suffix, especially with respect to light balancing filters.

[jon.oman]

Filters have always been an arcane art. Each manufacturer seemed to go their own way. The Wratten numbers were supposed to iron out the differences. But, you have pointed out that there can be and are discrepancies. I'll note that down in my copy!