Painterly roses

I have a client who requested that I submit pastel and painterly images, and I wanted to show her flowers against white backgrounds.  However, virtually all of my pictures were taken against black backgrounds.  To make this picture, I took a shot of red roses against black velvet and in Photoshop inverted the light and dark tones with Image > adjustments > invert (the shortcut is Command/ctrl I). That gave me a white background, but the flowers were now the complementary color of red which is cyan.  The stem, instead of green, changed to magenta.  To bring the red color back, I used the hue slider in the hue/saturation dialog box (Command/ctrl U) and that did the trick.  I abstracted the flowers with the Topaz Simplify 4 plugin.