Hello and welcome to Apple Support Communities, Gurudatha.
If I understand your post correctly, the preview turns to black and white once you've selected your printer from your iPhone. I'm happy to help.
Try these steps:
Check these things if you see the message "No AirPrint Printers Found” or have issues printing:
- On your iPhone, iPad, or iPod touch, check that your device has the latest version of iOS and that the app you're printing from is up to date.
- Check with your printer's manufacturer to see if any firmware updates are available for your printer model.
- Connect your AirPrint printer to your network using a Wi-Fi network or Ethernet connection. AirPrint devices connected to the USB port of an Apple AirPort Base Station or AirPort Time Capsule, or to your computer using Bluetooth connection, can’t use AirPrint.
- After you turn on your printer, wait a few minutes before you try to print. Some printers might take a minute or two after powering on before joining your network.
For more information, see the full article here: Use AirPrint to print from your iPhone, iPad, or iPod touch
Let us know if that resolves this issue for you.
Thanks for using the Apple Support Communities. Take care.