Visual cryptography schemes for color images usually is performed by expanding every pixel in the secret image into some subpixels in the shared images. Wang's schemes are secret image schemes based on XOR operation without expansion of the pixels so that size of shared images are equal to size of the secret images. The schemes are applied to RGB images. In this paper, a method to perform the schemes with minimal computation is proposed. The secret images in RGB color is transformed to YCbCr color model, and computation is performed only on Y component. The comparison of computation between RGB and YCbCr has been done. The results show that by applying the Wang's schemes in YCbCr can minimize the computation without loss of quality.