Hi I am new to Photoshop CS6, and photoshop in general. I am trying to take a color photograph, turn it to black and white, and reveal a flower in color and the rest is still black and white.
I thought I had done this properly when I added a new "adjustment layer, hue/saturation", reduced saturization to zero, and painted the yellow flower over with black to reveal the yellow flower's color while the rest of the photo is still black and white. And it worked..except when I got to the green stem of the flower. Painting over that with black revealed a yellowish-green stem.
I experimented a little more by painting black on the new layer mask and most of the rest of the color photo comes out wrong. The blue sky shows up like a weird smurf blue, faces are oddly peach/orange and most colors look much different than the originial photo. Yellow seems to be not affected, magenta/pink seems to be OK and blue shows up so-so. But the rest of the colors are messed up.
I know this must be something very basic, but why are the colors showing up odd?
Sounds like you did the right stuff. You should expect to see the colors revealed where the mask is made black. I might have used a Black & White adjustment layer rather than Hue/Saturation, as that would give you more control over the grayscale part of the result, but the technique with the mask should be the same.
Any chance you could take a snapshot of your screen, save as a JPEG, and paste it here? That will help avoid a whole lot of questions.
I noticed your screen name... I live in "bokeh". The weather has turned nice down here after Sandy passed by, eh?
Is it possible the flow or opacity of your brush is less than 100%? If it is it would take several passes of the brush to get your mask to true black.
And yeah I agree with Noel, a screen shot is worth a 1000 words. What I posted is only a guess.