tricky hair mask

[sevinne]

Hi everyone, I'm having a really tough time masking the hair on this image, client wants the shirt to change from white to dark blue, and there is streaky blond hair over the shirt that is totally ruining my day. I've tried the standard masking approaches - duplicated different channels and adjusted levels to increase contrast between the hair and shirt - but nothing I know how to do seems to fit the bill. Any ideas? I don't want to tell them I can't do it...

Thanks,

S

[AKMac]

Re: tricky hair mask

Nothing is impossible with digital retouching, but this is about as difficult as it gets.

[kateveber]

Re: tricky hair mask

Nothing is impossible with digital retouching, but this is about as difficult as it gets.

You're able to do that but it's really time consuming and likely possible to ruin the whole day.

[Benny Profane]

Re: tricky hair mask

Nothing is impossible with digital retouching, but this is about as difficult as it gets.

Yup, the only thing tougher is that hair over a white to yellowish background.

You're going to have to use whatever masks you created, and then draw in new hair after the color correction. Good luck.

[Vernon]

Re: tricky hair mask

Try what on this thread; perhaps you can find what you're looking for:

http://www.retouchpro.com/forums/photo-compositing/12802-extracting-blond-hair-black-background-destination.html

I think the part that may be key is this - The next step is to get the flyaway hairs. This is really difficult on this pic because the colour of the bg is so similar to the hair. Duplicate bg layer and accentuate the difference in colour between the bg of pic and the flyaway hair if you can, with whatever method you want. Next, and here's the weird part, sample the bg colour with the colour picker. Add a new empty layer and fill it with this colour and then change this layer's mode to difference. Next, isolate this colour with something like Select>Color Range, and using the colour picker click the background colour. You'll get a finer selection this way of the flyaway hair.

[Der_W]

Re: tricky hair mask

Try calculations, blue channel minus red channel (red as source 1), with an offset around 100 should give you a good start.
To make things even easier, if you still have the raw file, sometimes playing with the color temperature to extreme values can help a lot to differentiate things color wise.
Since you need to recolorize the shirt, some of the hair need to be adjusted as well, don't focus on creating an overly perfect mask, you're probably not going to need it.

[Repairman]

Re: tricky hair mask

I would use the pen tool to isolate the densest hair which won't be affected by the shirt colour changing (excepting bounced light of course). Change the shirt to blue and see what vestiges of the wispy hair remain. With patience and a 1 or 2 pixel brush you can paint in the individual strands on a layer and fiddle with the focus to soften them to match the background. With a little dexterity you may even be able to smear (with 2 pixel brush) away from the the main body of the hair to create strands. Any auto masking feature will require so much tidying up that I'd rather put the hard hours in by hand. Just getting a decent blue on the shirt will be a test in itself.

[klev]

Re: tricky hair mask

Just getting a decent blue on the shirt will be a test in itself.

This would be easier if everything could be imported unclamped, as is typical with video footage (ICCv4 supports that btw), but I don't have a good raw workflow for that. I would keep the raw file handy if necessary. It might need a slight (I mean slight, very easy to overdo it) decrement in exposure. Beyond that you can do most of the heavy lifting with channel mixer, then paint the shadow detail by hand in passes, typically hitting the deepest portions last. Use reference material to determine the correct range of saturation, and make sure it doesn't look obviously weird. I've definitely done this before. The thing is the hair is going to require some color correction. It looks a little greyish right now due to the influence of the white. It's going to have influence from the blue as well, and that will have to be painted separately. For the hair mask itself I kind of agree with you, although I would just concentrate on getting a nice flow to the shape. It might be possible via quickmask if you have really good painting skills. Otherwise pen tool. Feather as necessary. If it's problematic due to darkened gamma artifacts, you can always cut the hair out onto its own layer, rebuild shirt underneath, fake a slight shadow there (again seek reference if it looks weird), and the shirt will be very adjustable independent of the hair. Both will still require adjustment. I hope that helps.

[Repairman]

Re: tricky hair mask

The method I use Klev, is to mask off the shirt, and work with 3 or 4 active layers of the shirt shape. The original (for hilites), a solid blue of the target colour, a black and white version and an 'approximate' blue version created in HSL with colorise - this version will be as close as possible to the target colour without drifting into silly colours or opaque dark tones. It doesn't matter how far off the target colour it is as long as it's blue and plausible as a legal colour in it's own right. I then use the individual CMYK channels as masks to create the tonal transitions and shirt detail on top of the solid blue and then blend the hilite areas from the 'approximate' blue selectively though the same masks or by hand. There are usually a few tries required to get the perfect mix of the layers but I normally get there. If you're very lucky you may find that the blue of the approximate colour will provide a nice transition between the blond hair and the darker target blue.

[klev]

Re: tricky hair mask

^^ That sounds potentially more productive than my strategy. I'm definitely familiar with colorize, although I don't use it that often. I do far fewer jobs in retouching now anyway, although it has been drifting that way for a while.

[Repairman]

Re: tricky hair mask

Yeh, colorise is not my 'go to' tool either but it's a good short cut to extreme colour changes when the Hue can't get you there and you temper it's destructive effect with some desaturation and/or opacity. Most of what I do ends up in print so I always have CMYK in the back of my mind even when working in RGB. Curves are nearly always my first port of call when handling colour issues, followed by Hue and colour balance. After that one needs to treat the other colour tools with caution for danger lies within! lol.

[klev]

Re: tricky hair mask

Yeah I typically use channel mixer for that sort of thing, but I too keep CMYK spaces in mind. Obviously they still differ depending on the output, but it's possible to remember where they will be more restrictive so as not to drive colors into territory that just isn't going to be fully printable.