Review of UHC filters, when they are useful to increase colour balance and contrast and when you should avoid them

D3300, M42 and UHC filters

I’ve got a Nikon D3300, that I didn’t “astro-modify”, so the red channel is weaker than the others. This, unfortunately, leads to incorrect colour balance in bright emission nebulae like M 42: an exposure time that gives you a good result in one channel may not give you a good effect in the others. Sometimes, I process each channel of my images separately, and when I do it I notice the wrong balance:

Fortunately, the UHC filter (Ultra High Contrast light pollution broadband filter) helps, especially in the light polluted area where I live! I have a PrimaLuceLab 2’’ filter and I’m very satisfied: no artefacts in the image, very good contrast and colours. In my experience, a single 60 sec shot to M 42 with the filter gave me a better result as compared to an entire sequence without it (see the previous post to take a look to the photo)! Remember that, since it’s a nebular filter, you can only use it only with emission nebulae, whose spectrum shows only H-alpha, H-beta and O-III peaks, that pass through the filter. Reflection nebulae and galaxies have a different spectrum that may be partially blocked by this kind of filters! Enjoy your filter!