chroma key green screen help

[kiltedscotsman]

hi i would like to try some chroma key green screen , my problem is where to start with the materials involved , especially the material for the green screen lots of them for sale , most reviews i find negative things like hard to get creases out see through

does any one know what is best for this , i am going to build my own frame, and hopefully get a lighting set .

any help would be appreciated thanks andy

[Manfred M]

How large of a green screen do you need?

One of the least expensive solutions is buying a roll of seamless chroma paper through a major photo retailer. If you do this. make sure that you store the box of paper upright, otherwise you will see creases and imperfections. The roll I have is made by Colorama; it is 53" wide (this is as narrow as it comes) and is 36 ft long and I paid just over $30 Cdn for the roll. If (when) it gets damaged, tear off the damaged piece and throw it out.

I use a commercial Manfrotto stand that I was given for Christmas a few years ago. Not as inexpensive as home-made, but it has a lot of advantages (like two high quality light stands that I can use when I am not using a seamless backdrop)

Stay away from muslin materials, you'll never get the wrinkles out.

Three other tips.

1. Make your life easy and light it VERY evenly. One large softbox on either side will work. Avoid hot spots; they are a pain to deal with. Don't forget you are going to have to light your subject as well and account for where that light falls. Unfortunately, you can't do this part of the cheap.

2. Keep your subject well in front of the green screen; at least 6 ft / 2 m and possibly more. otherwise you risk contaminating your subject with reflected light bouncing back on him or her.

3. While it may sound obvious; don't let your subject wear any green...

Don't expect perfection, you will need to clean up in post. Photoshop for stills and After Effects for video are the two tools I would recommend.

[kiltedscotsman]

thanks for the advice , decisions lol , trial and error i think will let you know how i get on thanks again

[Manfred M]

thanks for the advice , decisions lol , trial and error i think will let you know how i get on thanks again

Good luck - it can be fun, but I can't emphasize the importance of a good setup enough. I had the good fortune to have the use of a professional video production studio when I first learned green screen work, with a technician to set things up. Reproducing similar results in my makeshift home "studio" was quite frustrating and at least 80% of the time was spend getting the lighting set up just right. Get the green screen lit properly first and then add the lighting for the subject.

There's a reason that you don't see a lot of amateurs doing this and it is because it takes a lot of time in both the capture and post-processing phases.

[rpcrowe]

I recently viewed a YouTube video tutorial on shooting Green Screen and then using the Perfect Mast segment of the OnOne Perfect Photo Suite to replace the background. This video took into consideration wrinkles, creases, etc. in the green screen; as well as overflow reflections onto the subject from that screen. Unfortunately, I cannot find the video with a YouTube search using "Perfect Mask Green Screen" as the search parameters.. It could be that the green screen technique is buried within some other YouTube Perfect Mask or Perfect Photo Suite video tutorial...

[Colin Southern]

My 10c worth ...

- Per Richard's advice, the paper is a zillion times better than the cloth.

- You MUST light it seperately.

- Evenness isn't necessarily as important as one might first think, because ...

... essentially, you have 3 zones:

Zone 1 is the subject

Zone 2 is the bulk of the green screen, and

Zone 3 is the thin "twilight zone" between the two

Zone 1 we don't care about because we're not doing anything with it (with regards to extraction)

Zone 2 we don't care about either because we erase it with a big eraser brush in about 5 seconds flat - and once it's gone we don't care if it was ever good or bad

Zone 3 is the only thing that matters - and this is where the fun starts. If you have something like frizzy hair or a fluffy animal it's hard because the way the demosaicing works; you end up with something that's not "green" enough to be selected cleanly, and it usually becomes a major PITA to get a clean extraction, even despite all the "wonderful" mask refinement tools.

To be honest, I seldom use chromakeys these days - it's usually far easier to just use the pen tool in Photoshop to select the object, usually cutting into the object by a couple of pixels and then using an appropriate drop shadow so that the transition isn't too abrupt (which gives a "pasted on" look).

Feel free to post some examples of images you'd like to extract and it might give us a better idea as to how it could best be approached.

[Manfred M]

I just found the link that was suggested to me as the best place to buy green screen supplies:

http://www.tubetape.net/servlet/StoreFront