[William Dempsey]

Hi all,

Chroma key and digital key products are not equal ! My personal tests conducted from 1996 to the present have, at least for me, shown that the more vibrant Ultimatte and digital keying colors function much better and allow the extraction of finer detail. “Chroma key” colors look like mud when placed side by side with products listed as digital key colors and the Ultimatte colors.

While I have several fabric screens I prefer Ultimatte green and blue painted surfaces. The fine muslin screens are as was posted above are not opaque and need to be stretched to get rid of wrinkles. The ones I have purchased have also had a slight yellow bias that makes keying fractionally more difficult than the painted surfaces I’ve used. I have not used the spandex screen material that is supposed to be really good but is rather expensive and limited in size if you want to avoid seams. The retro reflective products are expensive and seem to be a bit limited in size as well. From the days when I did front projection work with 7610 and 7615 scotchlite screens that type of material was also extremely fragile. I suspect the new materials are much more durable but probably not close to fabric or paint. Keep this in mind since I find talent typically does not hear the works “please stay off the screen”.

After meeting with the folks at Ultimatte ,they suggested that we use the smooth side of linoleum flooring which sweeps out nicely and takes paint well as our back drop material for small to medium sized screens. Note it is a bit fragile and can tear if abused. Also if you choose to go this way avoid deeply embossed patterns on the flip side as they can show through when flexed repeatedly. It is a good method of quickly making a high quality screen and moderately inexpensive. The inverted painted linoleum also makes a good keying floor and holds up to abuse very well. It is after all flooring material. The Ultimatte paint isn’t cheap but its easy to fix if marred. I’m still using the piece that I bought in 1997 as a floor extension.

In response to part of inital question, it is my understanding that green is better for video since there is more noise in the blue channel and green has a higher luminance. With film the blue sensitive layer of the emulsion is more sensitive making for better keying with blue. Also I have heard that blue requires more light which may be a consideration. Of course on set color issues are probably more critical. I have keyed with both film and video using both colors and have had good results with both. I should say that I use Ultimatte Blue which is lighter than most other blues even some digital blues .

With regard to on set color also be careful of yellow and yellow orange with green screens and pink and magenta purple with blue screens. I have found these colors can cause problems. Test before you shoot.

Regarding keyers I think all the products out there are good. I personally use DV Matte Pro and Primatte. I typically use DV Matte Pro since it is easy to use and pulls a great key. I have found that there are occasions where Primatte performs slightly better with some problem keys.Specifically, Primatte is a bit better with HDV that is hard to key due to its reduced color depth. Demo everything you can get your hands on and see what you feel most comfortable with.

Hope some of this is useful

Bill