Posts by hwjohn

Quote: Originally Posted by TomHuffman No, not even close. This is the correct method for converting RGB to xyY. The only question is whether you want to begin with RGB specifications or simply stay in the xy realm. Tom, Is the...

Quote: Originally Posted by TomHuffman Casey: I just realized that I had the math for the RGB-xyY conversion. I asked Greg Rogers about this and what he said rang a bell so I went back and looked at my spreadsheets and this was...

Quote: Originally Posted by stereomandan I know you know this, but if you enter those locations for Red into HCFR, you will see that they are spread all over the place. There is a very large gap between 50-75% and a small gap between...

Dan, Tom's Accupel and Bruce Lindblooms calculator both suggest the following targets for Red: 75% x0.574, y0.330 50% x0.456, y0.329 25% x0.366, y0.329 You can check out Lindblooms calculator on his site. If you input 1, 0.5,...

Well now we've done it. See what happens when you speak of that which we do not speak of? HINT: This thread isn't meant for discussion of what an IRE/volt/digital value is or the magical powers such entity may or may not possess.

Quote: Originally Posted by stereomandan If you keep everything to the x, y colorspace, it's quite simple really. Just imagine the x, y CIE chart to be a typical chart with X and Y coordinates. Saturation is the distance from...

I think the issue that Dan brought up is probably the reason the HCFR guys chose to keep it constant. I'm sure they knew exactly what the xy targets should be and how to get the correct RGB, so holding Y constant for them may have been...

Quote: Originally Posted by TomHuffman 190,95,95 gives the same xy as 100%,50%,50% x0.456, y0.329 so if this method is correct, then the correct targets are: 75% x0.574, y0.330 50% x0.456, y0.329 25% x0.366, y0.329 Why these...

Tom, I just tried normalizing the 50% red we are using (190,95,95) and put those numbers into Lindblooms calculator. Basically use 190/219 for R, and 95/219 for Green and Blue (Scale box unchecked). The resultant xyY is much closer...

Quote: Originally Posted by TomHuffman Something just occurred to me. The method I used for generating 25%,50%, and 75% patterns was to simply enter different RGB values into the Accupel. For example, to get 50% red, I would input...