For all orders, we always recommend converting the colors to CMYK mode.
This allows you to have greater control over the color values; as well as manage the consistency of the color values.
Colors will be converted to CMYK mode (as required) during the pre- press/proofing stage of your order.

However as there are several conversion methods the CMYK values produced may not be consistent, or the best match for your color. For this reason, we highly recommend that the conversion to CMYK be done to the original design file before uploading.