color spaces

[j2e4a8n]

Hi,

I am reading at the pace of a snail Professional Photoshop 5.

On page 17, he talks about channels and colour spaces.

"The cyan would have to be very light has cyan kills the desired red
Figures 1.5F and 1.5H are the only ones with light flowers, so one must be the red and the other
cyan."

Is to say that in cmyk the channels value represent the color values and that in rgb the represent the inverse of the color value.
In rgb if the white is [dark] red while in cmyk a white magenta would be a pale magenta.

[-default]

Yes, that's exactly right.  Later on in the same book, Dan makes this more clear.  I think of is as black taking away the shadows.  From the remaining image, cyan is red, yellow is blue, and magenta is green.  If there is no K channel, then the values are exactly equal.

[j2e4a8n]

In rgb if the white is [dark] red while in cmyk a white magenta would be a pale magenta.

Hi Jean

Do you mean that a dark magenta  in RGB  would equal a pale magenta in CMYK?

The other me.

[j2e4a8n]

Yes, this exactly what I mean.

[j2e4a8n]

Later on in the same book, Dan makes this more clear.  I think of is as black taking away the shadows.  From the remaining image, cyan is red, yellow is blue, and magenta is green.  If there is no K channel, then the values are exactly equal.

Mike is right.


You are wrong Jean me. They both about the same value .  .   .  ?!!!???


The other me.

[-default]

While "les deux Jeans" are duking it out, here's another way to look at it.

K = the darker areas of the image
Cyan = a paler version of Red
Magenta = a paler version of Green
Yellow = a paler version of Blue

BTW - I've had people ask me why C, M, and Y are not available as masks.  The reason is that R, G, and B always have more range and contrast.  If GCR is set to none, K is always zero, and the CMY values are equal to the RGB values