Y8/O22 differences

I'm trying to understand the difference in practice between using no filter, using a yellow 8 and using an orange 22 filter. I typically shoot with Tri-X and have always been told to use a yellow 8 filter under daylight.

I've got Way Beyond Monochrome 2 and Ralph's graph in there that shows the sensitivity of B&W film with and without a yellow 8 filter compared to the human eye is very helpful. I seem to keep coming back to the following questions in my head though.

1. Do you "need" a yellow 8 filter only under blue skies, on an overcast day does it make a difference? By "need," I think I mean that it's necessary to get the film to respond in a way my eye responds.

2. How about indoors when you're window lit by open sky?

3. Is there much of a difference between using a yellow 8 filter and an orange 22 filter? Out of habit more than out of knowledge, I use a yellow during the day and red 29 if I want something more dramatic. I rarely use the red filter.

4. I've found from my own testing that shooting Tri-X at EI 320 developed in HC-110 or D-76 is about right. With the yellow filter in place, giving a full stop of correction seems a bit much, so I usually expose at EI 200. Do other people find that a full-stop of correction is a bit much under daylight?

Thanks in advance,

Jonathan

I use 2/3rd stop for a yellow filter. Another option is to meter through the filter, if you are using an external meter.

Yellow filters block blue, which means that they reduce the amount of light in shadows since most of the light in shade is blue light which has diffused / scattered into the shade. The implication is that shade will lose details, as will shooting under overcast conditions.

I mainly use yellow (and orange or red) when trying to darken the sky. I typically do this when most of the subject is in full sun or mostly in sun. I don't do this when the subject is indoors / in shade, since the outside light is so much brighter than inside, and the blue blocking mentioned above.

There is no point in routinely usings filters unless you wish to create a particular effect. Yellow, orange, and red filters will darken a blue sky and make any clouds stand out. The effect is red > orange > yellow. If there aren't any clouds then the effect is lost. Look at the insert for a particular filter it will give a filter factor which should be used to determine exposure. When using a filter, it is not a good idea to use the cameras' metering as the color sensitivity of a particular light cell may distort exposure values. As said use the filter factor. There is always some degrading of image quality since two more surfaces are added to the lens system. Filters need to be kept very clean becuase of this. There are several other uses for filters but I think this should answer your question.

Some people routinely use a 1A filter as a transparent lens cap to protect the front element of the camera lens.