Quote:
Originally Posted by gregbradley
Hi Marcus,
Well here's what I have been doing lately and sometimes it has worked wonderfully and other times not as well so consistency can be a problem.
I use CCDstack to get up to an LRGB combine and then save it as a RAW tiff.
I process the Ha in CCDstack and save it as a RAW tiff.
Now I open the LRGB in Photoshop and process it with multiple levels/curves
until it is bright and the histogram is bell shaped. Then do bits and pieces until I am happy with the LRGB.
Now I open the Ha and convert it to RGB mode from grayscale.
I then do levels/curves etc and bring it up to the point I like it.
I then create a new layer on the LRGB and copy the Ha to that layer and delete the green and blue channel. I set this layer usually to screen rather than lighten although sometimes lighten gives a better result. Opacity usually about 50% or less. Now I duplicate that Ha layer and set that to "saturation" and opacity to probably only 20%. This brings out the Ha colour and give control over the colour. This approach gives rich colours and no salmon hues.
I then create 2 more new layers and one is assigned to the blue channel and maybe only 10% and the other to luminosity and again to suit but not too much. This last step will shrink stars to more the Ha sized tiny stars but
I find if you go too hard you will get a dull halo around a bright core for stars and it doesn't look good.
...
When you say you work to match star sizes what tools do you use to accomplish that?
Greg.
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Hmmm, blending 50% or less Ha on top of an LRGB layer? Doesn't that mean you'll lose 50% of the information in the Ha? Adding a small amount to lum later may not be enough. For my Lum/Ha blend I always layer Lum on top of Ha and adjust the opacity of the lum layer so that all of the Ha detail shows through and I grow the stars.
I never add the lum in CCDStack - I only create RGB there. I export RGB only as FITS as I recently bought Eddie Trimarchi's FitsPlug PS plugin to import (and export) 3 layer FITS images - much cleaner than converting to tiff. If an R,G or B channel has bloated stars I'll extract it and do a star reduction and paste it back in. I have my own PS action to reduce star sizes but I'm now finding Noel Carboni's action is better (of course?). Matching also means discarding subs (usually because my focus is off). Now that I've got a Robofocus though my subs will hopefully be more consistent
Cheers, Marcus
