Image Help - - help me realistically change background color

retouch1 · #1 02-07-2007, 02:01 PM

I am having a heck of a time REALISTICALLY changing the background color on a friend of mine's headshot. The shot is overexposed a bit and he wants a navy blue background / or a navy-white gradient of some sorts. Please help. I have tried simply selecting the background only and filling with blue, but the hairs on top of his head are impossible

I have also tried extracting, but same deal with the hairs.
HELP! Advice on a technique please?

madclark · #2 02-07-2007, 02:12 PM

Try masking his face and using color burn on the background. Just simply using a color layer won't read since the background is white.

madclark · #3 02-07-2007, 02:24 PM

Check that. I guess you'd want to use linear burn if anything with a layer you've filled in as the background color and a mask.

Stray hairs are always tricky but you'd probably have some success doing a general mask and then fixing the rest by hand. Or you could use Katrin Eismann's technique for masking hair. Take a color layer with the greatest contrast between the background and the subject. Duplicate it as an alpha layer and adjust the contrast and curves to make the contrast greater until you can simply paint in black the rest of the subject. That should make a pretty good mask that you can globally adjust through levels to get the edges cleaner or fix by hand.

klassylady25 · #4 02-07-2007, 02:49 PM

gradient tried

philbach · #5 02-07-2007, 03:28 PM

Retouch1, welcome to retouch Pro.

Well Navy is pretty drastic. This is a lighter blue. I used two shades of blue and the render clouds filter to make the background. I also desaturated the background some.

As for extraction I didn't do a real careful extraction but I would first recommend that you use the pen tool to outline everything but the edge of the hair then use Russell Brown's great tutorial on extraction. Click Here . When you get down to the site and scroll down a while to get the quicktime movie file tutorial. Its very helpful for this kind of technique.

Good Luck.

KR1156 · #6 02-07-2007, 03:43 PM

read up on using channels to mask images out....then remember that this man was shot against a white background and the flyaway hairs will have an ambient light affect when you mask him out, modify those flyaways to look like they were shot against a dark background.

madclark · #7 02-07-2007, 03:51 PM

How about something like this?

I always find switching a light color to a dark color so tricky because the masking has to be fiddled with to get it just right for believability.

On the mask, try using the paintbrush in the overlay mode switching between black and white and also the curves adjustment to perfect it. It will really add to the believability. I've also used a render clouds overlay on the background color to give it some depth as well as some general retouching of the face.

Let me know if you have questions.

KR1156 · #8 02-07-2007, 05:06 PM

nice going madclark....looks like you used duped layers with different blending modes...am i correct?

madclark · #9 02-07-2007, 05:54 PM

Thanks KR1156!

To swap the background color, I made a solid dark blue layer with a mask. I made the mask by making an alpha layer from the green channel and increasing the contrast and filling in the subject than copying that into a mask of the color layer. I reduced the color layer opacity to 50% but left it in Normal mode and then tweaked the mask to perfect the realism. I also created a layer with Render Clouds and clipped it to the new background color layer to add some depth so it wasn't too flat and unnatural.

You could probably make the color more vibrant and darker. It all depends on tweaking the mask to achieve the realism. Overlay even the slightest bit on the outline of the subject and it ruins it. With the subject as well lit as he is, I think it would be pretty hard to go too deep and dark though without making it unrealistic.

You're absolutely right about the ambient light. That's hard to recreate in going from very dark to very light or vice-versa. This kind of change is much easier if you work toward a medium toned replacement like my example. A Linear Burn layer seems better suited for this but again you'd have to hand tweak the mask I'd think.

Otherwise it was just some general beauty retouching - clean up the skin tone and tweaked the eyes and lips.

I really recommend Katrin Eisemann's book on masking and selections. I learned so much from it.

retouch1 · #10 02-07-2007, 06:04 PM

Wow! Thanks for all your responses. I can't believe there are so many different ways to achieve this effect. Experiment time!
Thanks again all.
-Retouch1

cardmnal · #11 02-07-2007, 09:13 PM

Hi retouch1,

I think you may have been on the right track using the extract tool. Once in the extract interface be sure to click smart highlight and use a rather large brush I used a size 80). This really helps doing in the hair. I extracted this one in about a minute. I added a white to blue background gradient using the white at the top of the image this took care of any problems with ambient light in the hair.

I could have taken more time and done a better job but I think you will get the gist of it with this.

mistermonday · #12 02-07-2007, 10:44 PM

On some images, channel blending and mask making are the only way to go. However, on other images, a simple use of the extract filter will make this a 2 minute job.
Regards, Murray

Lasa · #13 02-08-2007, 07:23 AM

If the hair is the problem...have you tried the extract filter? I should work ok for this image....if not use the GML free plugin (enter a GML search here or look in softwares.
I used the GML for the attached image...makes cleaner extractions without the halos the extract filter tends to leave behind...

Lasa