Green xray film & green filter light meters

[kirkmacatangay]

Hi Everyone,

I have some green sensitive xray film. I am planning to take it out for some nature shots. A few posts have said that depending on the lighting conditions they rate their xray exposures differently. Open shade - faster ISO, and dusk - slower ISO.

Has anyone used a green filter in front of a spot meter to get exposure changes under different lighting conditions? Other then uprating the ISO to take into account the filter factor, can this be trusted method to deal with differing lighting conditions for green sensitive film? Or is there something I do not know about light meters that will prevent use in this fashion? Does green sensitive film 'see' in the same way as a green filtered light meter would?

By extension, will a green filtered incident meter be useful in the same way?

I have a Minolta Autometer IVF with a 5° spot attachment.

Kirk

[Corran]

I think people do that more with blue-sensitive film, since shade will have a lot of blue light and such. I use the Fuji green x-ray and I've never changed my ISO like that. However, if I was photographing right at sunset with really warm red light I might - but I don't usually shoot b&w sunsets myself. Also watch for items that are green, because they will be very bright - such as trees and foliage.

[Andrew O'Neill]

I've been using green sensitive for a few years now and I've never changed the ISO, except when I want to compress or expand the tonal range of the negative. Kirk, I don't think you need to worry too much about it.

[ic-racer]

If you are going to filter the meter to match the x-ray film, think about how you might be better off using an averaging meter. For example a 'view meter' where you can see a portion of the scene to average to get you reading. If you put the filter on the spot meter, you are likely to get some odd exposures. For example, if you are metering a leaf or grass or some colored object with your spot meter, do you know enough about the films response to previsualize that? For me, it is more straight forward to use an averaging meter.
Also, I don't think there is an ISO defined for x-ray film exposed to white light. I suspect you are referring to an exposure index you are using to estimate an exposure that will give a printable negative. How are you figuring your exposure index?

[Sevo]

The human eye has a strong green bias, so a green-peaking film is going to look quite natural as is, without filtered metering. Exceptions will be dominantly red sceneries or those with red illumination - but it is unlikely that some arbitrary green filter will match the film's yellow to red response (and some might even make matters worse), so you'll have to bracket whatever you do.