One other problem is that &quot;real&quot; black and white images don&#x27;t come from the same distribution as greyscaled images. The training data is just regular photos that have had all the color channels combined and averaged together. Sometimes it&#x27;s a weighted average, like green is given more weight than blue, because human eyes see green better.<p>However real black and white photos represent the actual intensity of the light waves. Black and white photos might be sensitive to light humans can&#x27;t even see, or weight different &quot;colors&quot; very differently. Even two colors that appear the same to the human eye might be different intensities and frequencies, and so produce a different black and white photo.<p>I don&#x27;t know how much of an effect this would have. But real black and white photos definitely look different than greyscaled color photos, and it might lead the NN to guessing the wrong color information.