PDA

View Full Version : strong cyan filter?



Daniel_Buck
21-Mar-2010, 22:45
So, this is kind of nerdy I think, but I'm wanting to build a pair of anaglyph glasses out of camera lens filters, probably 52 or 55mm.

Basically, anaglyph glasses use one eye red, and the other eye cyan. The red filter is no problem, I guess it would be either a 25a or 29, that completely removes cyan (blue green).

My question is for the cyan filter (blue green), what number designation should I look for? I'm not real familiar with blue or green filters. Which one would be the most "pure" cyan, cutting out all the red light?

the cheap result below works perfectly, but I'd like to make something out of glass filters and metal frames, Ben Franklin-esq style, haha!


http://www.3d-display-info.com/files/3d-display/images/anaglyph-3d-glasses.preview.jpg


http://gizmodo.com/assets/resources/2007/04/steampunkspex.jpg

Peter K
22-Mar-2010, 02:34
Daniel, for visual use a Wratten 25 is much too strong compared with the filter used for taking pictures. With such a strong filter one cannot see much details in the shadows. A Wratten 23 A is much better. Or a red-orange filter (http://www.schneideroptics.com/ecommerce/CatalogItemDetail.aspx?CID=612&IID=3598) like this.

For the second filter you can choose a cyan conversion filter made from Schott "FG" glass, simalar to Wratten 80A as offered by Helioplan KB-15 (http://www.heliopan.de/produkte/konversionsfilter_blau.shtml) or Schneider (http://www.schneideroptics.com/ecommerce/CatalogItemDetail.aspx?CID=1161&IID=3591) "Konversionsfilter Blau". Both offers also the stronger KB-20 filter.

Have fun

Peter

Doremus Scudder
22-Mar-2010, 05:47
A Wratten #44 is the cyan "minus red" filter for color separation work. Maybe you can find one of those... I've only seen them in gels myself.

Best,

Doremus Scudder

Daniel_Buck
23-Mar-2010, 11:32
Daniel, for visual use a Wratten 25 is much too strong compared with the filter used for taking pictures. With such a strong filter one cannot see much details in the shadows. A Wratten 23 A is much better. Or a red-orange filter (http://www.schneideroptics.com/ecommerce/CatalogItemDetail.aspx?CID=612&IID=3598) like this.

For the second filter you can choose a cyan conversion filter made from Schott "FG" glass, simalar to Wratten 80A as offered by Helioplan KB-15 (http://www.heliopan.de/produkte/konversionsfilter_blau.shtml) or Schneider (http://www.schneideroptics.com/ecommerce/CatalogItemDetail.aspx?CID=1161&IID=3591) "Konversionsfilter Blau". Both offers also the stronger KB-20 filter.

Have fun

Peter

Thanks for the replies!

Does the 23 A cutout all of the cyan? it needs to cut out all of the cyan, or else the stereo effect will not work. Same with the cyan filter, it needs to cut out all of the red. will a KB-15 or KB-20 cut out all of the red?

I have seen a wratten 44a listed as "minus red", that sounds like what I want, right? what's the KB equivalent to that Wratten 44a?

Peter K
23-Mar-2010, 12:55
Daniel, the stereo effect works also with cheap "glasses" made from cardboard and foil by the "Karran group" and others. And works not only with cyan but with green foil also. (Tried five minutes ago ;) )

Conversion filters don't cut out all red because one will get realy bluish gost-like faces if used with daylight color film and tungsten lamps. Also there is no KB equivalent for Wratten 44 and 44a because this filters are band filters. Such filters have two sharp edges. Conversion filter have shoulders.

Peter