Fully agree. Let's just continue with the research without personal agendas or ambitions.

Yes they are. You can see that the blue channel levels reside at higher levels for the filtered version. This means recording colors with better precision. Another thing is that the camera uses less gain for stronger color signals.

Instead of purple filters, how about a minus green gel for testing?

@svart Deducting Green is the same as adding magenta. Compressing the contrast and pushing colors upward is just adjusting the green - magenta shift. Encoding uses progressively more precision and latitude for brighter f-stops. Hence the filtered color channels have already been recorded and encoded with better precision.

For best results for white balancing compressed images I recommend to try Silkypix. It has a slider 'color deflect', which is often a great tool for this. The GH13 material is not quite high quality enough to white balance entirely all the time, but GH2 material might be. Haven't tested yet. Hopefully will soon.

Certainly magenta can be eliminated very well from jpeg images taken at 3k resolution, but only RAW images allow white balancing fully in post. For me there was a need for beefier colors, not more accurate.

The issue is actually not about light, but luma/chroma ratio. Chroma is too lean and encoded with too few bits causing mosaic and banding. It has been proven already to be rather effective way to add chroma and have a flatter picture profile, both at the same time. If you are not capturing beefier colors and flatter contrast on location, you are missing out. There is no way to fix them in post, other than using some band-aid technique.

This thing definately does work. The image i'm getting out of my gh1 is incredible, and would be better with an ultra con and/or a black pro mist. I don't see why everyone is getting all worked up about this. Try it if you want to, don't if you aren't interested in the extra time it takes to get what is, imo, a better looking image. It does make the image better, and I have zoomed in and noticed problems on unfiltered images that I didn't find with the filtered and corrected image. At this point using the filter is quite a pain to get the colors back to where they should be, but there is an improvement. In saying that, however, it is the subject of the film that ultimately matters and not slight increasing in detail in the red and blue channels. People not using this method will continue to enjoy their gh1/gh2, and those using it might just enjoy using it slightly more at the cost of some extra post time.

@Diffusion33 All I know about B&W, at least on the GH1, is if you shoot max iso of 3200 in color, it's FPN galore. If you shoot it in black n white smooth, it's very usable. Noisy, but cleans up good with some light noise reduction. Don't think using a color filter to shoot BW will do anything.

But, if you shoot in color with the filter then convert to BW, the extra color information in blue and red channel MIGHT help.

I have a small video on YouTube produced using GH1 and these methods combined. It's meant to test the low light capabilities. If it's okay to link to it, here it is:

I could answer on behalf of leckel1996, the images have been taken with a magenta lens filter on and later color grading is applied on one side of the image. Basically shifting green - magenta ratio in editing program should white balance the image and restore normal colors. In practice different software and methods yield different results.

Aki.. Would you consider trying the same workflow using a magenta shift in-camera ? No color filter, just use the WB settings.

Did you see the banding during playback ? What player did you use ?

I learned that there is a program freely available called WinFF. It is a graphical user interface for ffmpeg conversion program that you can use to batch convert MTS files to AVI files or image sequences. So no need to start coding new software. ffmpeg does an excellent job converting MTS files.

There is plenty of new information for Project Blue Light worth a mention. I have made several videos using ffmpeg to convert first to HuffYUV AVI files. I edited the video as usual in HuffYUV and exported the edited video into image sequence to be graded in Silkypix. This way it is possible to save the grading as the last step and really massage the colors to one's liking.

One such video is now on-line, if it is okay to link to it, here it is:

This is a small video filmed indoors in diverse lighting conditions, and it came out really fine. Even the YouTube version is largely free of banding and posterization and does not immediately look like it was filmed with a eur 300 Lumix GH1 and eur 100 Tokina 24 mm lens. Worth to have a look.

Other mentions are about the lenses to use with magenta filter. I have noticed that some lenses work better with magenta filter than others and the images are more easily balanced to one's liking. An excellent lens hood is mandatory item to avoid purple haze that lowers contrast and is difficult to remove in post. I found an old big lens hood padded with non-reflecting material and this clearly improved the image (however not yet used on the video linked above).

I plan to post an update about all this on my website hopefully real soon.

It appears two additional CC filters might be handy. Those would be yellow and cyan. For example, if you needed to pick bluish or yellowish hues in secondary color correction and had to boost those, it would help if the blue channel had been captured on location with the widest latitude. You could try this;

White balance the camera for white having a yellow filter in front of the lens. Remove the yellow filter and attach magenta filter. Expose the image so that the blue channel has full range. Examples below. Now the blue - yellow slider will work very well in editing program and one could pick both bluish and yellowish hues with ease. Yellow high lights will bloom just like they should. Yellow hues are captured by the blue sensor, they are just phase shifted. Likewise, if you had to pick reddish or cyanish hues it would be good idea to make sure red channel is exposed for full range. So using a cyan filter (opposite of red) when white balancing would accomplish this.

Good brown hues would depend on whether they are "yellowish brown" or "reddish brown". This way we could optimize the limited palette of the camera for grading. So the grading actually starts in the camera for best results.

Also, for film negative the primary colors are cyan, magenta and yellow (the opposite of primary colors for video). So one could see we have a filmic approach to the colors with these CC filters. As always, I am trying to create a bit better article about all this.