Gel filters / glass codes

Yusuf Aslanyurek · November 20, 2004

is gel filter numbers are same as glass (4x4 camera filters)

and why every campany have other numbers why they are not using some standart like -20mrd +12 CC ???

80A blue, 81 yellowish, 82 blue again no sense.

Laurent Andrieux · November 20, 2004

80A blue, 81 yellowish, 82 blue again no sense

At kodak's even numbers are for bluish, odds for ambers, that's why.

Gels and filters don't have the same numbers because... they're not exactly the same.

A point is that gels' manufacturers are not filters manufacturers.

Ther is no standard, as far as I know. the kodak's wratten is somehow a norm for filters, that is widely used, but the numbers are typical of one manufacturer, thats all.

Though I'm not a gaffer, I think some gels' numbers are the same at Lee and at Rosco, but I'm not so sure.

Edited November 20, 2004 by laurent.a

David Mullen ASC · November 20, 2004

A filter like an 85B or a Coral contain a unique mixture of dyes designed to create a certain look, so it's not as simple as calling it a CC# Yellow + CC# Red, etc. filter. Not that the Wratten number series makes any real sense either, but it is quite old.

Harrison & Harrison came up with a more logical numbering system that describes color shift plus light transmission, but no one but them use it.

Tiffen also has a line of Decamired filters with use the Mired shift numbering system to change the color temperature in certain directions.

The Wratten system has stuck around because photographers have been using it for so long.

Yusuf Aslanyurek · November 20, 2004

Thanks all.

David, can you explain Harrison's system ?

and who can be sure of gel filters have a same numbers or not (rasco or lee not important)

Laurent Andrieux · November 20, 2004

gel manufacturers give you sample shades with caracrteristics, numbers, etc... You can get ones at your local lighting rental

Michael Morlan · November 20, 2004

Everything you could want to know about Lee versus Rosco versus Gam Color here:

http://members.aol.com/dazipguy/ColorConversion.html

and here:

http://www.prolightware.com/gel%20color%20conversion.htm

Edited November 20, 2004 by mmorlan62

David Mullen ASC · November 21, 2004

Harrison's system is to start out with Magenta, then Blue-ish Magenta, Blue, Cyanish-Blue, Blue-ish Cyan, Cyan, Greenish-Cyan, etc. ending at Red and then Reddish Magenta.

Given this progression, the numbers below 10 are colorless (like UV filters) and then Magentas start with 10, and every 5% change in light loss is given a new letter of the alphabet, so that a 10C transmits 5% more light than a 10D, for example (their chart also tells you that a Magenta 10C is the equivalent of a CC05M).

The Yellowish-Red filter 79H is the equivalent of the Wratten 85B filter. "H" means that it transmits 60% of the light passing through it.

Trouble is that you can't tell anything about a color unless you memorize their numbering system, nor the filter factor unless you memorize their lettering system. But does make more sense than the 81, 85, etc. Wratten series.

What you do learn is that according to their chart, a Coral filter has an 80 number, while the 85B filter is a 79, meaning that their Corals have slightly more red in them than an 85B filter. But other than that, an 80H would in theory be a close match in color and density to the 85B, since that is 79H in their system. An 80H is a Coral 6, by the way.