Info on Chrom-Key Please..........

mghaner

Can anyone give some info on using Chroma_Key Backgrounds? With Christmas coming up I have some customers that want to have Christmas Portraits done. A decient background is about $180 so I was thinking about using the chroma key system. You can get a bunch of BGs on CD so I thought that would be cool, cost less, and give me many more options then buying actual Muslin type BG's. Does anyone use Chroma Key? Can anyone show me some examples of Chroma Key BG's in the finsihed product? Thanks in advance for any help you can give me on this.

All the best, Mike

wxwax

It's not as easy as it seems.

I've shot folks against a keyable background, here's what I ran into.

You have to get very even lighting on your background, so it's easily selected and removed. Your subject can't be too close to the background, or you'll get reflected light on them, which will screw-up your selection. And of course, they can't wear whatever color you choose for your keyable background. And making a clean selection of hair is always a tough deal, with the potential for taking tons of time.

What seems like an easy way to change backgrounds might end up being more work than you expect.

Should you go this route, I'll be very interested to see if your experience is a good one.

ziggy53

wxwax wrote:

It's not as easy as it seems.

I've shot folks against a keyable background, here's what I ran into.

You have to get very even lighting on your background, so it's easily selected and removed. Your subject can't be too close to the background, or you'll get reflected light on them, which will screw-up your selection. And of course, they can't wear whatever color you choose for your keyable background. And making a clean selection of hair is always a tough deal, with the potential for taking tons of time.

What seems like an easy way to change backgrounds might end up being more work than you expect.

Should you go this route, I'll be very interested to see if your experience is a good one.

Sid is giving good advice.

If you really want to pursue, look at Corel KnockOut 2 and [FONT=Verdana, Arial, Helvetica, sans-serif]Ultimatte for better control. I used [/FONT]KnockOut 2 at my previous employer and it works well, but still takes time in extra preparation and processing requirements. In most cases, it was more trouble than worth.

If you blue-screen, you may often have to provide an inverse-colored rim light on the subject to eliminate a blue "halo" on the subject, cast by the background. Green-screen has a similar effect.

I think Reflecmedia and Chromatte is the current best technology, with the highest cost, but easiest setup.
http://www.bhphotovideo.com/bnh/controller/home?ci=1&sb=ps&pn=1&sq=desc&InitialSearch=yes&O=product.jsp&A=search&Q=*&bhs=t&shs=Chromatte&image.x=13&image.y=5


ziggy53

HeldDown

Either rent your background, or have a local lab print a big old banner post for you. You can probably get a 4'x8' banner printed for half what the BG would cost. Explore the option!

wxwax

ziggy53 wrote:

If you blue-screen, you may often have to provide an inverse-colored rim light on the subject to eliminate a blue "halo" on the subject, cast by the background. Green-screen has a similar effect.

Ah, very interesting!

mghaner

So I take it that no one on this forum has any examples of a before and after shot for me to take a look at. I would like to see one with the subject in front of the green / blue screen and then the finished product after the BG was added in the PP. Based on the response so far no one here has much good to say about them. Seems alot of places sell the stuff for them so it seems odd that so many places deal in them if no one uses them with success.

Mike

wxwax

No, I've never used their product.

I can show you how the reflected light from a keywall gets on your subject, though.

Here's an original size image. The guy was about 1-2 feet from the wall.

http://www.wxwax.smugmug.com/photos/60499672-O.jpg

You'll see green in his hair and on his face.

mghaner

Thanks wxwax, I can honestly say that I have felt that color myself before. If I remember correctly.........I think I have actually looked to be that color as well....Mike

wxwax wrote:

No, I've never used their product.

I can show you how the reflected light from a keywall gets on your subject, though.

Here's an original size image. The guy was about 1-2 feet from the wall.

http://www.wxwax.smugmug.com/photos/60499672-O.jpg

You'll see green in his hair and on his face.

wxwax

mghaner wrote:

Thanks wxwax, I can honestly say that I have felt that color myself before. If I remember correctly.........I think I have actually looked to be that color as well....Mike

I never go on boats.

tomthephotographer

I have shot Cromakey on several different shoots for paying customers. While it is true that the subject needs distance from the background I had no real issues using Photoshop CS. I saw one out of over a hundred in the Taekwondo shoot I did where the green reflected on the white dobok. It was my fault for the placement of fog. 100 percent Subject lighting 50 precent back drop.

And take lots of shots.

askme2flashu

Here is a thread from a forum I visit a lot. Link is to the first post. Some before and after shots in there somewhere.

I Simonius

mghaner wrote:

Can anyone give some info on using Chroma_Key Backgrounds? With Christmas coming up I have some customers that want to have Christmas Portraits done. A decient background is about $180 so I was thinking about using the chroma key system. You can get a bunch of BGs on CD so I thought that would be cool, cost less, and give me many more options then buying actual Muslin type BG's. Does anyone use Chroma Key? Can anyone show me some examples of Chroma Key BG's in the finsihed product? Thanks in advance for any help you can give me on this.

All the best, Mike

I was just looking at a book explaining how to do this the other day - but Im not going to tell you what it was

Sorry! Silly moment over ( too much coffee), HERE:
http://www.ilex-press.com/publishing/product.php?productid=16201&cat=0&page=1

In the explanation it shows you how to make abackdrop in photoshop- saving you a fortune in real backdrops!

Whether it works or not is another question but it sounds good in principle if you like photoshopping:):

wxwax

askme2flashu wrote:

Here is a thread from a forum I visit a lot. Link is to the first post. Some before and after shots in there somewhere.

No linkie.

wxwax

tomthephotographer wrote:

I have shot Cromakey on several different shoots for paying customers. While it is true that the subject needs distance from the background I had no real issues using Photoshop CS. I saw one out of over a hundred in the Taekwondo shoot I did where the green reflected on the white dobok. It was my fault for the placement of fog. 100 percent Subject lighting 50 precent back drop.

And take lots of shots.

Cool. Tom, you have any final results you can share with us?

LittleLew

Has anyone used the blendif advanced blending options to slide images in front of backgrounds or to remove Chromakey backgrounds?

tomthephotographer

wxwax wrote:

Cool. Tom, you have any final results you can share with us?

Sorry for the delay. I was hoping to get back from the artist in this project the final poster print he was creating however I no longer wish to wait. So I took one of the Photographs and created my own redition of what he was building to show what I had done on the Project.



The thing I learned here was that the green can reflect on the white with little effort on the part of the photographer. I took a background I am using elsewhere to give a taste of the power of this tool. I have recently ordered my own Chromakey and once the studio lighting is up to speed I will shoot some more .

Thank you for your thoughts and coments.

wxwax

Cool! Thanks for posting the "final" image.

mghaner

WOW, I posted this, got my answer quick and moved on. Now I check it out and see that it went on and on to give answers and info to many more. I am still amazed by just how great this forum is. I am on a few others as well, mostly equipment forums as I am one of the few on here that do not shoot Canon Cameras so I go seek out fellow "N" users. The others I am on are not nearly as much fun and the members are nothing like my fellow "muggers"
Thanks guys and gals, you folks are just wonderful.

Mike

tomthephotographer

mghaner wrote:

WOW, I posted this, got my answer quick and moved on. Now I check it out and see that it went on and on to give answers and info to many more. I am still amazed by just how great this forum is. I am on a few others as well, mostly equipment forums as I am one of the few on here that do not shoot Canon Cameras so I go seek out fellow "N" users. The others I am on are not nearly as much fun and the members are nothing like my fellow "muggers"
Thanks guys and gals, you folks are just wonderful.

Mike

Oh Isee lad a "N" camera user.... I guess we will forgive ya.. I use to shoot with "N" cameras and Curse "C" cameras back in the day but then "N" Got to big fer thier britches... Started ignoring thier customers... Did stupid things like put the auto focus in the camera body instead of the lens... So My "N" camreas were sold but one and the "C" cameras came to live with me. Before that I shot with "M" cameras but that got to expensive...

wxwax

mghaner wrote:

Thanks guys and gals, you folks are just wonderful.

Mike

We're also drunk. *hic*

TylerW

If you're planning on doing the bulk of your shots in chroma, what you save on backgrounds you'll be spending on lighting. You pretty much need a dedicated set of lights for your background, as well as the ones you still need for your subject. Flourescents work great for getting the even lighting you'll need, but you'll need some pretty strong ones (or a lot of them) to match your subject lighting.

Even still, you'll be setting yourself up for a lot of post production work. Once you have your keyed area knocked out, you can do a lot of stuff with color replacement to function like a spill supressor to knock that green reflection down, but its still a fair amount of work. If you're up for that, Chroma Key is a lot of fun. but if you're just doing it to save a bit of money, you may be setting yourself up for a steep an unrewarding climb.

I've done quite a bit of chroma key stuff, primarily for video (although my last project was in HD, which is approaching photo resolutions) and although I do honestly dread it, the final result can be really satisfying.