Forums
Sign In
Create Account
2
Using the colour wheel to select filters for black and white
Posted by Merco_61,
09 August 2022
·
1,200 views
Filters are subtractive, so they lighten their own colour and darken the reciprocal. To guesstimate the effect of a filter, you can look at the colour wheel and a sector of about 60˚ either side of the main colours for the filter will get the most pronounced effect.
This means that a red filter will lighten colours that span between magenta and yellow and darken colours from green to blue. A yellow one will make red to green lighter and magenta to cyan darker etc.
Using a good monochrome conversion app, you can set the exact position on the wheel you want, often with a slider so you see the effect in real time. Remember to choose your spectral response curve first as the filter will react differently depending on what film you are trying to emulate.
This means that a red filter will lighten colours that span between magenta and yellow and darken colours from green to blue. A yellow one will make red to green lighter and magenta to cyan darker etc.
Using a good monochrome conversion app, you can set the exact position on the wheel you want, often with a slider so you see the effect in real time. Remember to choose your spectral response curve first as the filter will react differently depending on what film you are trying to emulate.
I actually hadn't noticed it until now, I've been logged on all day, but was busy with other things most of the day. It looks like it would go hand in hand with my chart on Affinity Photo and work well with it, though the chart in Affinity is nowhere near that explainitave, it would be a good tool.
As for choosing a filter to use on a lens, it's excellent! Perhaps a few examples would help though of the same subject taken with various filters attached?
Here's how I do it in affinity. I snapped a shot with a D700 and 20-35mm f2.8 lens @35mm. Just a random color shot from my files converted to B&W and adjusted to my liking. I couldn't manage a screen shot in Affinity.