The best way to blend hairs on background change.

[Cyberek]

So, I hope, that the place is right, cosue question is from a pphotographic side... but....

What would be the best way to shot a model (I mean the color of background etc), so changing the background would be easy after all.

Afaik if a model has a black or dark hairs, one can use white (blown with 1 or 2 stops) background, then use the "multiply" blending mode to change background, and just mask to finish the effect.

But what about with blond hairs? What would be the best way to shot blondie, and then what approach to take when changing the background.

Same with semi blond (aka 50% grey in b&w), what then?

Of course I'm thinking about situation, when while shooting, I dont know, what the final background will be, so matching the background on photo is quite impossible.

Thanks for any advices.

[slipchuck]

Re: The best way to blend hairs on background chan

best way to do it is buy a background color that is green. that way it is the same color as the "green" channel in photoshop. you can double that layer and make a mask out of it. then either delete the background and fill it with another color or photo, or cut her out and paste her somewhere else.
this is the same as they do in the movies.... it is called green keying. when you watch the weather on your news station and they are pointing at the weather map, it isn't really there.... it is just left of the camera. the weather screen is either red, green or blue just like the RGB channels in photoshop

hope this helps

cheers

randy

[mistermonday]

Re: The best way to blend hairs on background chan

Cyberek,
My experience with blonde hair is that it has red and green components. The best results I have found have been with a blue background. This usually gives you the greatest amount of contrast and gives you exceeptional flexibility when using Apply Image and Calculations commands to create high quality masks. Moreover if you happen to do any work in LAB color, you will automatically have a high contrast image in the B channel which contains the diametrically opposed Blues and Yellow of the image.
Regards, Murray

[Cyberek]

Re: The best way to blend hairs on background chan

Randy, Murray, thanks for answer.
Beside blue/green screening (which is not always available), do You, as retouchers have a favourite methods to work with cuting blond hairs and persons from background? Do You prefer blondies on black background or white?

Ps... so that Was my 100 post

[mistermonday]

Re: The best way to blend hairs on background chan

Cyberek, congratulations on your 100th posting. You will be at 1000 in no time.
There are a number of discussions on this topic. Here is a link to one of them I recall on RP. Within that thread are links to other threads and tutorials. I personally prefer a black background if the photo is shot with proper lighting. Flyaway blonde hair is often very translucent and can provide a significant challenge to extraction against a white background.
http://www.retouchpro.com/forums/pho...stination.html
Regards, Murray

[Cyberek]

Re: The best way to blend hairs on background chan

Tanks Murray for this excelent link.

[Macint0sh]

Re: The best way to blend hairs on background chan

greenscreening isn't the end all be all. you WILL get some color spill on the edges.

If you can get a good contrast doing it, i think masking from gray background is the best way to go about it.

[ray12]

Re: The best way to blend hairs on background chan

There is a technique we use to get single hair strand accurate detail extractions from models on a background.

We do not use green or blue. Green and blue came from the old TV days and most photographers way over light them... and they become strong green or blue hair lights from behind... if you know what I mean. Black or Brunette hair isnt too bad to cut out...but blond hair is somewhat transparent or translucent and it actually "refracts" the green or blue light within its hair follicles itself... and you end up with understandable and very ugly contamination within the hair strands themselves.

We here in NYC have begun using a slate gray background to do extractions if we want absolute perfection. We also use a $139 plugin called Vertus Fluid Mask which has a gorgeous edge blending tool that actually works as hoped. As long as we dont overlight, or get highlights or shadows at the edges, or complex backgrounds at the edges of the hair...then it comes out cuting single strands of hair with no halos or fringing in just about 3 minutes with no other masking or channels or other mask build-up techniques necessary.

With other channel build up mask techniques we used to spend an hour or two only to find out we had over done the channel contrast and we had to start all over again from scratch.

Cheers,

Ray12

[snook305]

Re: The best way to blend hairs on background chan

Ray How do you get the grey to go more white when you are using the channels.. Or are you saying that fluid mask works better with slate light grey back grounds?
I have tried light grey but whe I go into channels it is harder to dodge and burn to get the grey white for the masks...
Do you have any other tricks to get the nice mask with light grey?
I also use KAtrina eesimans double mask with one being smaller than the other and throw the middle larger one on multilpy gives me the best results when blending to new Background...:+]
Thnaks for an further suggestions on your light grey technique...
Snook

[Cyberek]

Re: The best way to blend hairs on background chan

I also use KAtrina eesimans double mask

Could You write some more about that technique (maybe some link)

[ray12]

Re: The best way to blend hairs on background chan

Hi Snook,

We dont regularly use the channel or the layer extraction techniques any longer. In this economic environment, we have needed to be able to do precision hair extractions in minutes preferably...rather than the 45 minutes we used to take with channel masking.

Channel masking was the best we had for a while...but we almost always found ourselves "over doing it" on the fine edges...and then... wanting to start all over again because we ended up creating white halo edges, blurs, and ugly looking matte clumps at the edges of the hair.

Today we use a different technique... using slate gray backgrounds as we said in the last post. That helps us get rid of all the color contamination issues created by the overly lit and overly saturated blue and green screens.

Also, MisterMonday hit it right on the head...No matter how you cut it...blonds are more tricky because their hair is translucent... and the cutout colors actually get colored into the hair itself. To fix that problem we had to create hair repair brushes...so yes it always takes longer to do blond hair.

In response: Here is a link to a video clip showing how the hair is cut out... not using the channel or layer masking techniques to get those fine edges. Sometimes its clearer to show it... rather than to try to describe it in words. Use the full screen to see it better.

http://www.screencast.com/t/d2qn6p9z1

Cheers

[snook305]

Re: The best way to blend hairs on background chan

Thanks ray, you ate one of the most helpful people here.. I personally will try fluid mask but do not usually like plug ins b/c usually they still need fine tuning anyaways which makes it more diffcicult if you do not have a mask to work with...?

Could you throw up a blonde girl and try it, do you think fluid mask would work better with a darker back ground on a blonde girl? darker than slate grey , maybe a darker grey?
Just coriuos as I am pretty happy with the katrina eissman technique but yes blondes are always harder!!!!
Thanks a lot for taking the time to do the video screen cast!
Snook

[Cyberek]

Re: The best way to blend hairs on background chan

ray12 - thanks for the video. Didn't know, that fluid mask does so great job. I have tryed it back in the days, but it was afair 2.x version, and results wasn't good. Have to try the plugin again.

snook305 - any link to "katrina eissman technique" you have mentioned?

[Greg Curran]

Re: The best way to blend hairs on background chan

I use a lot of "hair brushes" as well as the techniques mentioned above, you can do a search for them and download most for free, or even create your own.

[ray12]

Re: The best way to blend hairs on background chan

Hi Snook,

No thanks on cutting out a blond! LOL

I have enjoyed Katrin's masking method for years...but recently I have mostly abandoned using "Channel Contrast" masking because it easily takes me 30-60 minutes for each mask...and then when im done finessing the fine edges...I usually end up "over working" the edges... and I end up feeling like starting the mask all over again quite often. I also used to have problems with halos on the edges of fine hair, fringing, black or white matting, and having the hair clump up when placed over different background colors. Channel Masking does seem to still be good for coarse detail hair or fairly smooth edged hair... but it often lacked the precision on very whispy fine detail cutouts and it had these overlay problems.

Yes, You are totally right with using a darker background for cutting out blonds.

There are 3 things that hair cutting software needs to work well. It needs a "luminance or brightness difference" between the hair and background to tell where the background ends and the hair begins. It would also like to have a "color difference" to work against... to differentiate between the background color and the hair color. And it wants to be able to detect a texture change if possible. If you can give the software 2 or 3 transition "Clues" to work with...it does pretty good.

So... we have ended up using a very dark royal blue background for blond models. The darkness allows the blond "brightness" to stand out, the blueness color gives it some good color difference to work with (blue and yellow are opposite on the color wheel - so they create great color difference for detection) and the smoothness of the background gives it some edge transition detail to be able to spot and identify the hair. Any strong texture component in the background will confuse the software because the hair is also textured...so the software doesnt know When to start or stop the edge detection without a smooth background. With this combination we get pretty good consistent results with blond cutouts. This combination of factors might also be photographically helpful in creating some pretty good "channel mask" Clues to create visual separation in the channels as well

The TV grade blue and green screens out today are just too bright, too saturated, and create so much colored spill and color contamination that we have moved away from using them. They were great for television because the TV sensors were fairly low res compared to our DSLR's today. So today we use the slate gray background for precision black, brown and red hair cutting...and the very dark blue for cutting out blonds.

Also, if your images are not shot in the studio with helpful separation elements... real life (in the wild) cutouts can be quite a challenge because they often do not have the best brightness separation in all spots, the color separation may not be there, and the competing and conflicting background textures can create quite a havoc (try to cut hair shot against trees!). So yes... start your collection of hair edge brushes... to patch out and repair the bad spots.

Its real easy to have a bad hair day...when doing detail masking!

Cheers