Photo Compositing - - extracting blond Hair for black background-destination

pure · #1 02-09-2006, 02:26 PM

hi,

i have to extract 12 x60MB TIFF images, with girls in front of a white background. unfortunately i have to set them all in front of a black background

i have only 1 week for it, the whole body is also to extract but thats the fast part of it. additionally i have to repair the skin (and do this with 14 more images of that series, which remains on white back)

i said "very good planning", but the shoot is done and cant be reshot.

so i would use the masking technique back and forthmasking as i do usually,
and maybe paint a few thin hairs then later (difficult with mouse though)

any idea how to extract it faster but still looking "real" ?

- using extract tool in PS CS2 ? i never did, hm.
- using knockout 2? i could use it, but never did, is it easy without practice?

i am very practiced with my bezier-tool and with back/forth masking in the mask-channel, and i prefer it and like it, but it could be simply too slow reg. the time limit.

any idea, would be glad!

thanks

mistermonday · #2 02-09-2006, 03:24 PM

Pure,
Start by checking out this RP thread. For hair, especially fly-away or whispy, the Extract filter does not do a great job. Knockout is not much better.
Sometimes these extractions are much easier than you would think ut it depends on the color and contrast relationship of the hair to the rest of the image. I suggest that you post an example image here and see what ideas come back which are specific to that image. Here is the link.

http://www.retouchpro.com/forums/sho...ht=superfrasky

Regards, Murray

studioj · #3 02-09-2006, 03:52 PM

I have to strongly recomend this video:

http://av.adobe.com/russellbrown/AdvancedMasking.mov

pure · #4 02-09-2006, 03:55 PM

ok

http://homepage.mac.com/purepeter/Si...rary/haare.jpg

bart_hickman · #5 02-09-2006, 05:09 PM

This looks delicously fun. You have three light sources which must be separated from one another--the background, the foreground, and the strong highlighting of the hair strands. Do you want the glowing highlighting of the hair-strands to be preserved on the new black background?

Bart

pure · #6 02-09-2006, 05:31 PM

Quote:

Originally Posted by bart_hickman

Do you want the glowing highlighting of the hair-strands to be preserved on the new black background?

Bart

no, not necessarily. the photographer said its enough exctracting the thick hairs and medium thin and leave the ultra-thin ones out.
maybe painting a few thin i thought, i dont know.

in general it doesnt mind what i do, it should only look natural

studioj · #7 02-09-2006, 05:44 PM

Pure, you can get the ultra-thin over the black with Russell Brown's method.

Trust me

mistermonday · #8 02-09-2006, 06:58 PM

The fly away hair is basically the same neutral color as the background except at a different lightness (89 vs 99). My only hope here was lab. I moved the image to LAB and did a curve adjust by setting a point on the L at 89 and then nudging that point way down. What happened was all the fly-away hair remained bright (99) while the foreground hair got very dark. This left the backgound at medium gray. Using Select> Color Range and adjusting the fuzziness, you can select just the background and in 1 minute you have the makings of a good mask. It needs some touch up but I will have to work on it later. Of course by that time Super Masker Bart will likely have figured out a better way.
Regards, Murray

Flora · #9 02-10-2006, 01:34 AM

Changing backgrounds for flyaway, fine hair is something I've always liked, and still do, to experiment with ... but up to now, there hasn't been a result making me go 'WOW' when changing from a White to a solid Black background ....

They are the 'non colours' at the extreme opposite from each other and therefore, in my opinion, such a drastic change will always look a bit 'fake/pasted/you name it' ... Specially because, as Bart very rightly pointed out, 'the strong highlighting of the hair strands' is due to the particular conditions and background in which that shot was taken .... if the background would have been solid blue, like in the case of the link Murray provided, 'the strong highlighting of the hair strands' would have a strong bluish/cyan cast .... and whatever has colour and therefore information, can be changed ....

In this case the background in nearly white and the highlighting of the hair strands is even lighter ....

Bart asked "Do you want the glowing highlighting of the hair-strands to be preserved on the new black background?" .... I know Bart can work magic in 'impossible' extractions, but, in this case, in my opinion, if you preserve the glowing highlights against the new black background, it will make the lighting look wrong (I'm no photographer, but I think white reflects light back ... black tends to 'absorb it toning the highlight in the hair in a completely different way ..) ... and will be a dead giveaway of manipulation indipendently on how good and accurate the mask might be....

If you tone the highlights down and try to splash some colour in them, they will look rather flat and lifeless ... a far cry from the glowing highlights of beautiful healthy hair ...

The other alternative is to 'eliminate' the lighter flyaway strands ... which can also be an unsatisfactory compromise ....

I might try the procedure for myself .... but I don't know if the result it could be considered acceptable for commercial use ...

Mig · #10 02-10-2006, 01:49 AM

Here is an extraordinary technique that I learned from someone.

You'll need to do it in steps, which is typical for difficult selections, especially hair.

Start by selecting the main hair portion and copy it to a new layer. (You can probably get this selection quite easily from the channels, if you know that trick.)

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.

The end result here looks quite poor, but this picture will never look good no matter what you do if you intend on putting it on a black background.

Your idea of painting hair is an excellent idea. Doing this and disorting the strands with the ripple filter will help give you a pretty good illusion of natural hair.

Also, you can forget about trying those one touch type knockout methods, like the extract or others like it. They won't work for this type of thing. You need to use channels and whatever advanced methods you can pick up - like this one. There's no easy way unfortunately.

good luck,

Mig

Flora · #11 02-10-2006, 01:58 AM

Mig,

You are right .. it is one of the best ... and it was the first I tried ... but,

Quote:

Originally Posted by Mig

....but this picture will never look good no matter what you do if you intend on putting it on a black background.

... that is exactly the point I was trying to make with my previous post ...

Gary Richardson · #12 02-10-2006, 02:03 AM

Can't open the attachment on MIG's post. No problem with other attachments.

Mig · #13 02-10-2006, 02:04 AM

Yeah, you're right Flora - this doesn't work and I don't bother with it when I see this problem.

One trick though, to get around the difficulty of selecting flyaway hair when all you want to do it change backgrounds is to cheat and and keep all the flyaway hair + the superfluous colour around it, and then when you switch backgrounds, then make sure the colours around the strands of hair are the same in the new background. I know this is common sense, but it's a good trick for those who are stubborn and want to try and select every last pixel of hair. It'll only drive them crazy.

mig

bart_hickman · #14 02-10-2006, 02:06 AM

The first thing I tried was the background eraser tool in Paintshop Pro. I did a couple of other easy tweaks after the BGE, but that's the main part. That's the first attachment--took about 10 minutes including tweaks.

For grins (or so I thought), I tried the defringing mask method, which took 45 minutes and there was some hand brushing (I hate it when that happens.) That's the second attachment.

Neither looks completely natural, but I think the BGE is a bit better-looking. Maybe some brushing in the hands of someone with artistic talent (not me) can help finish it off.

I did a third BGE version with a bit more aggressive erasing. The right side looks okay, but the left side looks a bit weird.

Bart

pure · #15 02-10-2006, 02:07 AM

Mistermonday:

first i would like to ask if there is any risk converting the ECI-RGB into LAB and back? i am afraid of it in case of loosing any information or pixel.

if there is no risk at all. i will follow your instruction

Flora:

yes youre right. i think it willl never look real "good" but as compromise i would follow your instruction.

Mig: very good result, i will try that and eliminate the fly-around hairs by using some of the layers-option-palette menu (multiply or luminosity or whatever, i try)

thanks you all