Difference Between CC10R and Tiffen 812 Filters?

Neil Walden , Nov 01, 2004; 07:05 a.m.

When Kodak announced the cancellation of Kodachrome 25, I bought a lot of this film and froze it. Now I'm near the end of my supply. I've used Kodachrome for decades, like the results and feel comfortable with it. To continue using Kodachrome, I'll have to switch to K64. Kodak's information on "Reciprocity Characteristics" indicates a CC10R filter is needed with K64 for exposures of one second, something that was not necessary with K25. I don't have a CC10R filter. I do own a Tiffen 812, which has a slight red warming cast to it. To help decide whether it justifies buying a CC10R for very occasional use with long exposures, is the color difference major or minor between the CC10R and the 812?

Responses

B G , Nov 01, 2004; 09:23 a.m.

The 812 is supposed to be "fleshtone" color, whatever that really is. cc10r is just red, not brown.

You could try the 812 and see if it "looks good" at long exposures. But also try no filter to see how that looks. If you don't like the 812 and the no filter photos look too cyan, get yourself a cc10r. I suppose you could just get a gel filter and tape it on carefully for very occasional use.

Chris Wetherill , Jan 07, 2005; 02:24 a.m.

Picture your CIE chromaticity diagram for a sec, since a graph is worth a thousand words. A Tiffen 812 is above the line of CCxxR filters which extends from the illuminant off to the right. In the case of D65 as the reference white, an 812 is about as far to the right as a CC12R or CC13R would be and almost directly below an 81B light balancing filter. It's about 1/4th to 1/3rd of the way up from the CCxxR line to an 81B. So while it's close to being a CC10R it's a tad redder and it's got a bit of color comp in it too.

That's the visual appearance of the filter. How it responds with various color films is another matter. Here's where perhaps the biggest difference between an 812 and a CC10R is: the 812 absorbs UV, CC filters do not.

The 812's transmission starts to roll over at 420 nm, is down to 50% transmission at 400 nm, and by 380 nm is passing just 10% of the light. Depending on the exact spectral sensitivity of the blue sensitive layer in your film (as well as how much far violet and near UV there is in what you're shooting) you may get a minus-blue (+Y)effect of some magnitude with an 812. Without some fairly detailed calcs it's difficult to say how much, but this effect is to make the 812 behave more like a color comp filter.

It's only a rough guess, but with typical color films I'd consider it to be about 1/2 color comp filter (81B or 81C) and 1/2 CC12R -- all that on top of a UV absorber.