Lab Mode is a great way to convert images to black and white without a lot of hassle while achieving very good results.
1.) Open an image in Photoshop and set the image mode to Lab. Image > Mode > Lab
2.) Next, open the Channels pallet and move the a and b channels to the trash
3.) Convert the image to Grayscale. Image > Mode > Grayscale
4.) Got to Image > Adjust > Levels and adjust to your liking.
That’s all there is to it! Here is the converted Lab image.