Mystery yellow filter

Can anyone provide information about this filter, manufacturer approximate date possible rarity? It is a push on no threads.

 

Only the obvious.

 

29.5mm was a common 1920s to early post-war filter size (e.g, 29.5mm filter | eBay).

 

yellow enhanced the sky/cloud, although this one is very light.

 

from Modern Photography 1950-10

 

As you can see in the eBay listings, even top-quality filters of this period are not worth much. Coatings were primitive, mountings are awkward, and so on.

Edited June 24, 2021 by JDMvW

You are spot on as to the size. It is on an IKOFLEX II 1937. It is a bit darker than appears in the photo I'm guessing at least one stop. Thank you for the further information.

You are spot on as to the size. [...]

Ah...!

Here's another bit of info: it was made by P.M.P., in France.

;)

Ah...!

Here's another bit of info: it was made by P.M.P., in France.

;)

Yes I am aware of that however I would like information about P.M.P., is it still in business if not when out of business, etc.

I'm guessing this is either a Type #3 (in Wratten nomenclature) or a faded Type K1 (#6 in Wratten nomenclature), pre WW2 filters used for 'Daylight correction on panchromatic materials for outdoor scenes, including sky'.

The yellow coloured dyes in these two particular filters were unstable whereas the dye base in a #12 Yellow was very stable.

I cannot assist you with P.M.P. Possibly a French pre WW2 manufacturer that did not survive the 1940s .......