Color Filter Help

[Darkhorse]

I must be doing something wrong. I've been slapping an orange or red filter on my OMs and I feel it's not coming out the way it should. When I look at the negatives, the information on them is scant. By that I mean the negative isn't as dense as naked lensed photos I've taken. When I try to emphasize the sky darkness that should result I get graininess. And I don't think there should be perceptible graininess on iso 25 film!

I know this is may seem obvious but I AM underexposing, am I not? Despite the fact that I'm using the TTL metering and the OM2's patented off-the-film metering in Auto mode. Here's what I'm talking about:

The two bottom left images were with a red + polarizer. The far right was metered using manual metering on the foreground, the second straight ttl which told me to underexpose -2/3. Not a whole lot to work with there!

The two on the right, top and bottom were done using an orange filter. The bottom one seems OK, maybe because there was a lot in the foreground I dunno (another shot with a lot in the foreground came out fine with a little medium gray sky in the background). The top one, eh, it seems a bit underexposed. The two top left ones are naked.

Do the negs look normal to you? Am I doing something wrong? Should I meter on the sky only? Should I meter with a gray card? Any tips for using color filters would be appreciated.

 

[Darkhorse]

Anyone? Little help?

 

[ZorkiKat]

You have to consider both film and meter sensitivity to colours. Not all panchromatic emulsions respond to red the same way- some are more sensitive to others. Same with meters.

Using polarizers can also fool the meter.

When testing a new emulsion or a camera's meter, allow some extra exposures- under and over to see what the exact exposure adjustment really is.

The filter factors can be useful. Use it and figure the new exposure setting by factoring it against the original exposure without the filter.

Or you could be seeing the negatives differently. Those shot through red filters and polarisers tend to look thinner than those shot without filters. Through a dense red filter, only 1/3 of the visible light is used- therefore in the picture, 2/3s of the objects' reflected light also disappear.

Too much exposure from over compensation will often cancel filter effects.

See here for some filter basics:

http://www.zorkikat.com/filter-basics-for-black-and-white-photography/168/