Quote:
Originally Posted by willus
I hadn't intended this as a test of the grayscale conversion algorithm in the devices, but it certainly is interesting. The checkerboard pattern I put in the PDF is full (100%), either red, green, or blue. The Kobos convert the red, green, and blue to 52%, 86%, and 26% of full white, respectively. The Kindle 2 converts to 50%, 33%, and 17%, respectively, and the PW2/Voyage convert to 9%, 35%, and 12%, respectively. Interestingly, none of these match the commonly used grayscale conversion ITU-R BT.709 or BT.601, which are 21%,72%,7% and 30%,59%,11%, respectively, but the Kobos are definitely closest, proportionally, which explains why they look more natural. It is particularly strange to me that all of the Kindles weight the RGB components significantly differently than the ITU-R weightings (K2 has red weighted the highest, and PW2/Voyage have blue weighted more heavily than red). That seems clearly flawed, and would be trivial to correct. How odd. |
Fascinating information. I will add it to our wiki. Thanks.