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Is there a penalty for mixing color spaces? (Main graphics)

If I write drawing code in Core Graphics on Mac OS X or iPhone OS, I can set the color of the active fill to red by calling:

CGContextSetRGBFillColor(context, 1.0, 0.0, 0.0, 1.0); // RGB(1,0,0)

If I want a 50% gray color, I can call:

CGContextSetRGBFillColor(context, 0.5, 0.5, 0.5, 1.0); // RGB(0.5,0.5,0.5)

But for shades of gray, it is tempting to make a shorter line and call:

CGContextSetGrayFillColor(context, 0.5, 1.0);

However, this function is NOT just a call to the RGB method with an intensity value copied three times; instead, it changes the color space of the context from DeviceRGB to DeviceGray. The next call to the RGB method will switch it.

I am interested to know:

  • What is the punishment for switching color spaces?
  • Is there a fine for painting if your context color space does not match your device color space? (i.e., in DeviceGray and DeviceRGB)

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