@OldSmoke

Yes , for each chroma key color pick , all 3 chromas were disabled .

I like using the vegas one for very clean chroma keying, it doesn't work great if it had to deal with a lot of color range but I have like 4 chroma keying plugins in vegas and I like using the default one because of the simplicity and it's knack for doing the easy ones best. But If It's not an easy key I use something else.

Not sure what you try to achieve in the example above. Do you want to key the green rectangle or the purple background or both of it?

I found the HitFilm chromakeyer is one of the best available software keyers and zMatte which is part of DFT and to be used as Vegas Pro plugin is very good, too. For hardware live keying, Ultimatte still is on top.

@Marco.

only cutting the Green .

Hitfilm has issues with blues in the lower left corner , when cutting the Green . The Vegas NTSC color bars Hitfilm can cut the green bar , and a simple adjustment fixes the cyan bar's color . But here above , Hitfilm has even more trouble with the initial green cut . Difficulty getting the mask to go full white on the lower left rectangle .

Davinci still needs a slight tweak to get the lower right Red to come thru better . Overall , this is the best cut , for clicking on just 1 green pixel in the top left rectangle .

This is what I get in Vegas Pro with one Chroma FX used (I used a yellow plane below). I'll try HitFilm later. Though this example isn't a "real life one" for me.

the first pic was cut using Ultra-Keyer . I played with it best I could . I replaced the background with the green of the lower left rectangle of the source image( No Red this time ) . So now all green is uniform . In particular , after the cut , the lower left rectangle looks very much like the source image in the left pane . Colors are really good . Blue in the middle is accurate too . That gradient I spoke of is also gone . Essentially the same cut as Vegas , except Resolve retained color accuracy . Hitfilm is still up for grabs ( can Hitfilm cut this ? ) I guess that gradient had to disappear because it was green gradient up to the black tiny rectangle .

your Vegas cut is impressive . you're really good at it .I am not so good at it . just pointing out in this repeat pic that Daninci's cut with just the color picked , and No adjustments , was able to preserve the gradient in the lower right corner of the lower left rectangle . This may be extra critical , but seems Vegas can't keep that gradient .

I am interested to see what you do with Hitfilm . restore my faith in Hitfilm . Even if I can't do it , at least I know that it can be done( after you prove it ) . For now Davinci is doing it better . Source colors are retained and that nuance gradient is intact( No adjustments yet ) . ( seems I still don't know the technique of using Vegas's Chroma key , I will try Vegas again )

Real Life ? not really , It does show comparative quality of the cut . I have seen such colors in a pic . I added that little gradient patch as extra image complexity For now Hitfilm has huge issues "for me" , to get a good cut in the lower left rectangle . For now , Vegas cuts this particular image better then Hitfilm . Davinci still rules it though .

On Vega's behalf , I have made 3 green RGB bars of ( 0 199 0 ) ( 0 200 0 ) ( 0 201 0 ) . Vegas Chroma key can cut just bar 200 . Vegas chroma key can be very , very selective . this is cutting "green on green" .

This is a HitFilm Chromakey result:

But all we do here is just one of many steps to go for a good keying. This is pulling a clean matte only. Next is tuning the matte. Then suppressing the spill. Then light wrapping. Then background/forground re- color correction. This all together is what in the end makes a key looking natural and on it's way you would need to manage lots of compromises.

@Marco.

Thanks for doing that , That result is interesting .

for what you are able to do with HF Chroma Key . I did re-look at Hitfilm , I tried "color difference key" for some reason that was simple for me to use , and it cut it ! What ? I read in the manual that Chroma Key of HF is supposed to be the best thing ever , so why does "Color Difference Key" work so quick and easy on this ?

I kind of hear what you say about work flow . I do inspect Masks , both Status and Matte masks . sometimes those 2 masks look the same , at that point I think I have made some progress . HF's Chroma Key seems extra difficult for me to use , for some reason . I read the manual on HF Chroma key , and I read what you said ,...I will keep trying to get better at HF Chroma key .

for Any color , it will have to be somebodies Chroma key , but for blue or green , guess I have to go simple with Color Difference key of HF .

overall , I was surprised during HF's Chroma key color pick , that the initial color pick\cut was so far off the mark , compared to ( Vegas and Davinci ) initial cut . While Color Difference key of HF is very close to the anticipated result .

this is all i could do to get a decent cut , using Color Difference Key . If you ask me , HF "Color Difference key" is just as good as Davinci's cut . guess that makes Vegas the odd man out , for now , when it comes to cutting .

This tricked me too . in Vegas manual pdf , it has talk about using Mask Generator to make masks , and how perfect they can be , and be used . But , in the manual they multiply with a solid color replacement , that does look perfect . But they Never multiply with original image for a Cut , which always leaves the screen's fringe color that outlines the foreground ( Hitfilm has the same fringe color situation with mask multiply ) .

"I read in the manual that Chroma Key of HF is supposed to be the best thing ever , so why does "Color Difference Key" work so quick and easy on this ?"

It always depends on the source and what kind of "quality" one is trying to achieve. While one keyer seems to be pretty perfect for a particular source it may fail for the next, e.g. even the Vegas chromakeyer may work pretty fine for some kind of sources but may fail on others.
A real chroma keyer (which the HitFilm one is) and a color difference keyer share completely different mathes to pull the matte. There are color difference keyers which are damned good (the base of Ultimatte is color difference keying), but the HitFilm color difference keyer is extremely basic, close to the Vegas keyer, tons of further tuning controls in the HitFilm chroma keyer. Actually with the color difference keyer in this case I'm not able to achieve results as good as with the chroma keyer. A color difference keyer usually is good if the source color is very clean and unique and either R or G or B and becomes worse the more mixed the key color is.

In my case I doubt I would ever use sources like your graphic above for chromakeying. I would just assume if such a composite is thoroughly computer created it would use alpha backgrounds instead of colors. For this reason this isn't a good source to evaluate a key quality. It may demonstrate to a certain point some of the pros and cons of different keyers but it is hard to say how these properties would affect natural shots. How would the keyer process reflections, glass, shadows, smoke, motion blur, translucent cloth, spill, fine (hair) details, precise but smooth color separation, etc. There is no keyer available which is able to handle all of these tasks perfectly.
I see if I can find a resource for some good real life sources.

I think I found some good test resources now. This key stuff is free to use but it's not allowed to share the source files. You can download the resources from Hollywood Camera Work (I used "Godiva Medium" and "Godiva Wide" here).

That particular case is for testing to key translucent cloth. For some keyers it is hard to maintain the semi transparent areas and even much harder to maintain the original color then. Here you see how good the HitFilm chromakeyer works on maintaining color of translucent cloth (it's been a very quick key adjustment because it's only about the color here):

Now here are two examples where light wrapping and foreground color correction is applied to further match the key source to the background;

And this is an example demonstrating HitFilm's chromakey's quality to maintain details (footage from same source, called "Locked Backdrop"), see the fine hairs without spill :

The pic in Vegas Viewer is slightly cropped cause viewer is Best-->Full and Fit to Screen is OFF . Vegas cut it good , and I didn't sweat .

Vegas at times , can cut really easy . I eye dropped the color , and adjusted the 2 Threshold sliders just a bit . Nothing else . your HF cuts look really good . Did her dress start out blueish and turn kind of slivery ?

.

Davinci cut , I am not an expert on any of this . the dress here too , looks slightly different in the cut . I didn't try to recolor anything . still reading the BMD books . This pic I could not cut in Vegas . The dark area at top of green screen causing issues for Vegas ( to me it does )

Marco , your caped crusader pic is kind of what I was thinking about , but couldn't get there . a green screen pic with gradient . Can these programs cut complex gradient ? looks like HF and DR both can . Vegas runs in Project settings 32 bit Full gamma 2.2 , bit depth , So Vegas project isn't the issue . I have noticed , Davinci adjustments all have 0 to 1023 increments , 10 bit . I am not sure what Vegas and HF have .

this updated Davinci cut , fixed the arm area . like I said , I am no expert . Added Vegas cut , has green on her arms , transparency not too good .

update image , re-cut with Vegas . Much better , green remains on the arms .

Vegas , Transparency is good .with Settings

I relooked at Hitfilm . on this image . picked bright green color and adjusted Background , Foreground , and roll-back sliders. and it cut really good . Hitfilm's "Status" Mask , because of the transparency of the cape , she was still made solid white , while the cape was gray ( using the 3 sliders mentioned ) , That gave a real good "Matte" view of the Mask , Full ( black and white ) . At first I thought "Status" view should be made full black and white , Not this time . One of HF's chroma key tutorials , I think the guy says to start with background foreground roll-back sliders , and then Spillage , if necessary . The other controls are still somewhat vague to me . And they didn't go into detail of the other sliders . Right now , the best info I have on those extra sliders is HF's manual.pdf ver 12

"Did her dress start out blueish and turn kind of slivery ?"

In which shot? In this keyed one in HitFilm the color of her dress equals exactly the color of the unkeyed source shot. Impossible to get same good result in Vegas Pro. Vegas' keyer will always turn the cloth blue and using a float-point project for such 8 bit sources doesn't help. It's just the way the Vegas keyer works.

"Can these programs cut complex gradient "

Do you mean complex gradients of transparency or gradients of the (green/blue) background color caused by uneven lighting? You may download and test the "Smoke" sample footage from that Hollywood Camera Work resource.

"I have noticed , Davinci adjustments all have 0 to 1023 increments , 10 bit . I am not sure what Vegas and HF have."

Adjustments in Vegas Pro FX usually are based in ranges of 0 - 1 with 0.001 steps being displayed but internally it works even finer (you could at least type in steps of 0.0001 which would still being processed). Not sure about HitFilm.

Here are two results of that "Smoke" sample, left Vegas Pro, right HitFilm.

Lots of blue spill in Vegas Pro with a slight darker edge and it cuts away too much of the smoke while the background is still stained.

Then let's use a background being merciless but let's optimize the keying by using a mask and tweaking some adjustments. Again Vegas Pro left, HitFilm right:

From my experiences, usually only top color difference keyers like Ultimatte are that good in keying smoke, glass, motion blur or translucent cloth. Don't know how they made the HitFilm chromakeyer work this way, I really like it.

The composite , where she is outside , the dress became silver\grayish . The pic with the pinkish background is still blueish .

Your smoke cuts , really tell all . I have watched a few HF video tutorials . I kind of thought that a screen cut and than maybe smoke or fog got composited . But yeah , could be fog\smoke needs to be cut before it can be used . Gonna need a good keyer for that .

Digit resolution . I did notice Davinci's color picker is 0 to 255 8 bit per channel . And like with Vegas , the other sliders\controls are high resolution . either 0 to 1023 , or 0 to 1,000 . Both essentially 10 bit resolution .

If you ask me , SF\Wisconsin\Sony is the reason Vegas Chroma key is so bad . You have shown me that HF cuts nice , I need more practice with it .