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Discussion Starter · #1 ·
I've dug through all the posts on Kenny's Rosco filter solution for CRT projectors with MEC tubes. Most people seem happy with the results and I'm going to try them.

At the same time, however, I'm going to endeavor to build some prototype glass filters and I'm already working with a source for the glass. It should be thin enough to fit between the CRT face and the lens.

I need to gather some data that I don't have and would like to ask the community for help.

1. I need to identify the best color gamut for both DVD (NTSC) and HD material. I've found this great page as a reference, but I don't know which two gamuts to use. My guess would be to use SMPTE "C" and SMTPE HD and shoot for those RGB values.

2. I need to gather colorimeter (x,y) data for uncorrected MEC tubes and perhaps even VDC rebuilds if anyone thinks there is a difference.

The Kennys Filters post has some starting data and I want to confirm this is accurate:

For Green:
Testing them on the CIE chromaticity chart went like this:

Non- Filtered x-y coordinates were .5963 (y) .3531 (x)

Light filtered .6229 (y) .3305 (x)

Heavy filtered .6520 (y) .3145 (x)
For Red:
To add Red to those measurements:

Unfiltered...X=.6360, Y=.3632

Rosco 19....X=.6533, Y=.3467

Rosco 4690..X=.6550, Y=.3450
I'm also interested in getting numbers for blue to see how far they are off.

Any comments, data, flames or other input is appreciated.

- Jerry
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