Purple filter for B&W photography?

[ajuk]

Is it possible to get a purple filter for B&W I can't seem to find one.

 

[Jeff Kubach]

I never heard of one myself, if there is one what is it used for?

Jeff

 

[Pinholemaster]

http://en.wikipedia.org/wiki/Wratten_number

But why?

 

[CBG]

A magenta or purple filter is just be one more contrast filter for BW. Not very widely used but no reason it could not be deployed.

 

[Nicholas Lindan]

Get hold of a 3x5" Rosco swatch book and a 3x3" gel holder:

http://www.bhphotovideo.com/c/product/45190-REG/Rosco_8815_Roscolux_Designer_Color_Selector.html

The Rosco filters are good optical quality and the filter book includes the transmittance curve for each filter.

 

[tomalophicon]

http://en.wikipedia.org/wiki/Wratten_number

But why?

Used for minus-green and plus-blue separation.

 

[ajuk]

I thought it might be handy for some night traffic trail photography.

 

[fotch]

I think I have some Cokin that are labeled purple or violet, don't remember which. Maybe both.

 

[Sirius Glass]

Violet covers a set of wavelengths while purple is a combination of colors that occurs on or near the line of purple.