Strange B/W color desaturation

[firestone]

Hi,pls help..thks
1. Left image is RGB with Hue/Saturation adjustment layer - Sat 0%
2. Right image is CMYK with Hue/Saturation adjustment layer - Sat 0%
Qn: Why is there this reddish tint?
Clicking 'colorize'does remove the tint but its a bad conversion.

 

[firestone]

Oh well, qn been solved..in case anyone is interested. Thks for reading.

When you desaturate in RGB, the 3 channels are equalized and youn get a pure grayscale result. In CMYK, the Cyan, Magenta and Yellow channels are also equalised while the Black channel is adjusted to ensure correct lightness is maintained. If you run your eyedropper around the image you will see that the CMY values are all equal. However, that will not produce gray because in the CMYK model, equal amounts of ink do not equal gray or black.

 

[artfakeme]

If you are doing image editing, always do it in RGB Mode and then convert it to CMYK when u are done. For offset printing, images accepted for colour mode are in CMYK and Grey scale (black & white).

 

[agape01]

That is not the most effective way either.