I remember taking color cards and scanning them, then pulling them into Photoshop to look at. I thought I had found some very neutral colors. Prof explained to me that scanners, printers and monitors are not very accurate ways to analyze colors. It has to do with the equipment... the light spectrum of the scanner, the way monitors display colors vs. actual physical material. Basically he told me that what we use as consumers is purely for a pleasing visual representation of a color and is only a close proximity.
In a way I think that applies to most paints, even craft store paints. They are a representation of the color, but one that is pleasing to most people... a mix and blend but not necessarily a pure color. I think you can get close with those paints and colors, but for the depth and scope of what is trying to be done here ultimately we may need to find industrial/commercial grade pigments and additives i.e. items that have a higher QA process and actual tolerances to ensure each batch is uniform and the same specs as a previous batch.
I could be totally wrong here and completely off the mark.
If we think of the ultimate screen, one that does everything... gain, contrast, accurate color reproduction, ambient light absorption, controlled lighting performance, black blacks, white whites, reduced SDE... all that and more as 100% then all real world screens will be less than 100%. I think we all agree that mythical 100% screen is the theoretical goal, but we also understand it's not a reality either, not yet at least
Hitting the 80% mark for a DIY screen is easy, hell most walls that are even close to some kind of white meet or exceed that. Bed sheets and things of that nature come to mind at this level.
The next milestone is the 90% mark. Some off the shelf paints such as UPW, Misty Evening, Wispy Gray, Universal Gray (and now some of the other neutral looking grays listed in other threads)... all easily meet or exceed the 90% performance mark. Also in this range I would put Parkland(until some concrete data and tests are done on this material at least, after that is done it may fall in the 95% category), BOC, and most fabrics that have been used. These are all perfectly acceptable DIY methods and for most people will provide a pleasing screen for them. Some of these materials may even be pushing the next milestone, but without actual data that can only be stated as personal observation and speculation at this point. These observations may be dead on accurate, but when trying to convince someone on the other coast, or even in a different country that one particular DIY method is better than another, data is the only sure fire way a person can be positive about a decision. If a direct side by side comparison can be made in person, that would be acceptable, but most people can't see a side by side comparison in personhence the need for data and specs. Everything we buy as consumers is done based on specs, so DIY needs specs for people to be able to make informed decisions. Sometimes it does come down to a visual, and if something 'visually' looks better, damn the specs... but data and specifications are the starting point that everyone uses as a foundation.
Next up is the 95% milestone. This is somewhat harder to achieve, but still relatively easy. The main difference between this level and the 90% level is the cost factor. Quality went up, and so did price, but in the big scheme of things price is still very low compared to commercial screens. The other big thing that has changed from the 90% to 95% performance level is research and testing. More care has been done in selecting and testing materials in this range. Things like the laminates, Do-able, SMX, the more complex painting methods (more than just a single paint... a base coat and top layer) fit here.
Now for the fun... 95%-98%. This is where I feel most commercial screens reside, as well as the more complex paint mixes being used. LOTS of testing, research, and data are needed for this level. Sometimes I think a particular application may actually make this level of performance, but as to the reason why and how it works, that could be unknown. Sure everything was based on sound principles and ground work, but from a scientific and theory explanation it may not be totally understood. I'm not saying it was a pure guess; sure the person had an understanding of what works, what doesn't... and intuitively built on that experience to hit a higher standard. Before anyone gets in a snit over that comment, it wasn't a slam at anyone here, or for any past endeavors. Things like that happen all the time outside DIY screens, and it happens here too is all I am saying.
There have been house paints that were used for mixes and when combined with other paints and additives it changed from being ordinary wall paint. As good as a mix like this can be, I really doubt it will be able to hit the 98-99% mark. Even commercial screens have a tough time getting to this level of performance. I guess what I am saying is to get to the next step, especially one this high, it's doubtful off the shelf products are going to be the answer. (Personally I think this next step will be a hybrid method utilizing several methods)
Also, this performance range is probably only an interest of a proportional amount of DIYers. In other words most DIYers are looking for the 90% performance range. I will go as far as suggesting 90% fit into this category. They want cheap, easy and decent performance. 5% fit in the 95% range, 3% strive for the upper echelon level of 95-98%. That leaves 1 to 2% that would even attempt something at the 98% and above level. If it can be figured out how to make it easy (and some of the DIY mixes that went on to become commercial have, and joined the ranks of some of the other commercial screen paints) well this changes the playing field for not only DIY but anyone that uses a screen. We all need to keep that in mind for the end result make it so other people can duplicate your efforts.