Canon 400D + Hutech filter - why do stars look white but nebulae blue?
I was wondering why my shots of say the NGC 2070 have a definite blue green tinge to them - whilst the stars in the shots look white?
I am learning how to re-balance the colour and I can understand how a filter might affect how much light gets through of a certain frequency, or how a DSLR CMOS might be more sensitive to Blue than Red.
But what I don't understand is why if the colours are wrong are the stars white? Is it because the higher intensity light is correct, but the fainter light is blue / green shifted?
In Photoshop CS2 - what is the best editting technique to restore proper colour balance please?
My astonomiks filter did the same. I used a custom white balance to fix it in the camera or channel mixer in PS to line the colours up on top of each other. I guess the stars are white cos they've saturated the pixels.
Try and get the hystogram into colour mode so it shows the red, green and blue bell curves. Then you can change channelmixer between the 3 colours and use it to move the position of the colour bells left and right on the hystogram. Try and line them up on top of each other so the resulting colour on the hystogram is mostly grey and go from there. You need to move and release the sliders on channel mixer before it shows in the hystogram and also stretch the image to get the colour bells onto the hystogram in the first place. Stretch means to use curves.
