value of lambda_identity not to change the color

[rnqm]

1.I'm using cyclegan to do the denoising task. I find the color has changed a little. I hope the color not to change. Is it feasible to increase the value of lambda_identity? What's the appropriate value?
2.Also I wonder why loss_G_A and loss_G_B don't multiply lambda_A and lambda_B, but loss_cycle_A and loss_cycle_B multiply them with default 10?
Looking forward to reply. Thank you very much!