Z-Effects Blog

This is another part of the same post from VFXTALK, it will help explain how the channel shuffle works and how, when importing alpha or zdept (or any other monotone pass) to get it to work the way you want. The person had asked

“I have a black and white information , so is it possible to extract the rgb , cuz the shuffle node allows to take out only one channel?”

here was my reply

the shuffle will only take 1 channel this is correct but since white is the accumulation of all colors, any channel will do!

think of it this way, if pure white is (in u bit from 0-255) red=255 Blue=255 green =255 than middle grey would be r=128 b=128 g=128 and black would be 0 across the board

there by any sampling with in this range will have equal color range

for the sake of keeping with in nukes prefered pipeline i suggest using the red channel, though as i stated above it doesn’t make any difference.

edit for edits sake

basically what’s going on here is the following: the world of the rainbow is a magical place, and while most people think of this as san Francisco (go bay area) to us artists we are talking about color through light, if you were to take a prism and hold it up to mr sunshine (assuming your not in the Uk, than you have no idea what the sun looks like as it has never not been over cast) and watch the rainbow form, there are essentially all the colors in the visible spectrum broken down into a gradient, that to the human eye, seems to be rougher than a gradient as the TIR and refraction values for each color aren’t the same do to the wavelength. in other wards if you take you and 6 of your friends and arange them by girth (and or with) and shove them through a door at the same time, and push as fast as they can they wil all pop out at different angles based on their size and shape. the fat ones will most likely fall while the anorexic ones will most likely brake something. This is basically light in a more…human way

in nuke we take the basics of the and take only the primary colors RGB and the main reason for this is that they are clearly the prettiest of all the colors, also they are the most common power rangers! now to understand this we must take a ratio of cool power ranges to bad ones, and when we do this the result is we have 255 votes for each rg and b rangers, and oddly 255 votes for the black ranger, so we tossed him in as alpha. and thats where we get the channel shuffle, because as the seasons went one we started to exchange actors to the point where none of the originals are even there any more.

i’d love to go into cmyk but going into the teletuby’s vs barny friends ratio calculations requires a great knowledge of physics, color blending and a good education in children’s television that, as far as i’m concerned would probably take me about a day to type out, and to be honest wouldn’t be as beneficial as the power ranger rgb breakdown as we don’t use cmyk often in vfx 

-zander