Quote Originally Posted by marciofs View Post
What filter colour would you suggest to use when photographing close up green leaf and brown dry leaf on black and white negative?

I mean... Does Yellow or orange gives good results on green leaf? Does red filter gives good results with brown dry leaf?

I have Yellow, green, Orange, Blue and Red filters and I am avoiding spend money buying more filter.
Here's what I did when I was in your position.
I got a set of filters, and a color wheel. Filters on B&W will lighten like colors, and darken opposite colors. Try different filters, using the color wheel to get an idea what they will do and take notes of the filter and the exposure you used for each picture. Then, when you have your prints, you can decide which filters you like in which situations.
The general rule is to use the lightest i.e. least dense filter which gives the desired effect. Giving more exposure will slightly lessen the effect, less exposure will slightly accentuate the effect.
Again, keep accurate notes of the filter used and the compensation applied.