Photomechanical filters

[humdee]

Does anyone know the difference between a Kodak Wratten Gel Filter and a Kodak Wratten Photomechanical Filter with the same number?

Thanks

 

[artonpaper]

My limited experience suggests that the Kodak Wratten Photomechanical Filter is sturdier. They will be handled much more than the gel filters. In theory both would have the same light absorption qualities.

 

[AgX]

No.

http://i.ebayimg.com/t/Kodak-Wratten-PM22-Photomechanical-Filter-10-2cm-4x4-Square-NEW-Old-Stock-/00/s/MTA2M1gxMDk0/z/q44AAOxywCJRbkGU/$T2eC16R,!)kE9s4Z+l5jBRbkGUQQg!~~60_57.JPG

This is the backside of of a envelope printed as carrying a "Wratten Photomechanical Filter".
As you see the text indicates that it is a cutable, not to be touched filter. Thus a gel filter.


Maybe as colour seperation filters can also be used for pictorial photography Kodak just packed those useful/intended for colour seperation work also in those special envelopes.

 

[humdee]

Thanks for the replies.
Both types of filters are gels and they both have exactly the same handling warning on the package. The only difference I can see is that the surface of the Photomechanical filters seems to be just about completely smooth, while the "regular" Wratten gels are usually a little bit "dimply." Could the Photomechanical filters be a slightly higher quality?

 

[edp]

The best "photomechanical filter" is the spinning turbine on a Goerz Hypergon.