How to reduce haloes.

[ollypenrice]

Hi All,

Steve asked me to post this demo of my star curve routine though, when I say it's mine, I'm sure it's widely used.

Begin by making a circular selection a little larger than the halo, concentric to it, and feather it. Ctr H makes the selection invisible as on the screenshots, but it is there.

Open Curves, put the cursor on background sky just outside the halo and Alt Click. That puts the bottom (dark) marker on the curve to pin the background sky inside the selection. You don't want to change that. In this case the input and output levels are fixed at 22.

Grab the curve just above the pin and pull it down till the halo goes.

Then gently restore the curve with other grabs higher up.

Sometimes the colour balance may need adjusting inside the selection.

The size of selection and the degree of feather depends on the size of the star and halo.

Olly

[RobH]

I use exactly the same technique Olly

[ollypenrice]

Thought you might!

It's the logical way, really. Maybe being rigorous and doing it colour by colour might be ideal?

Olly

[antimorris]

Agreed that it is the logical way. I tend to process my channel files separately before combining so if needed I do run it color by color, but it depends on the image and whether its needed on all channels. Also kinda depends on whether I do tone-mapping or just straight up processing. When tone-mapping I only run it on what will be my Luminance (i.e. Lum or Ha) if it is necessary.

I think, as you assumed, that it is at least a fairly common way to do it, but definitely always nice to share effective processing methods with others - it seems as this hobby becomes more popular (yay!) there is quite a desire/demand for "free help"

[SlipperySquid]

Cheers Olly, all these little tips really come in handy but I do fear that this new one will have pushed something else out of my mind!

Oh and I bet Rob's only saying that to look, "Wind swept, fab and groovy" like your good self Olly .

Matt.

[RobH]

Oh and I bet Rob's only saying that to look, "Wind swept, fab and groovy" like your good self Olly .

Matt.

Don't know about 'groovy' Matt

[ollypenrice]

...but, being hairless and aerodynamic, my head is a disappointment to me in cultivating a windswept look...

Olly

[steppenwolf]

Thanks for posting this Olly - exactly what I wanted to see.

[roundycat]

I have been doing it like this for years and often treat each channel separately although I always process the whole picture at once rather than in channels. Sometimes this can cause a dark halo which can be lifted by raising the LH end of the Curve to give what looks like a most un-natural shape but one which works.

I still cannot make up my mind whether it is better to select in Quick Mask with a softish brush or use a hard brush and then feather normally. Either way, the size of the selection and the degree of feathering is critical.

Dennis