Photo restoration or old enhancing methods
Back in the days of early photography when shutter speeds were slow and lens quality was being improved all the time, photographers strove to get the best results possible, even if it meant applying a few photo enhancing tricks of their own.
Lenses in the infancy of photography weren’t as optically perfect as they are today and the scene needed plenty of light and long exposure time. The sensitivity of the “negative” was also a contributing factor. The less sensitive the light capturing medium the more light or exposure was needed. This type of camera would have been the very early Daguerreotypes around 1830 to 1860
As a result of these long shutter speeds subjects had to sit for several minutes. They often took a posture and facial expression which was comfortable. Smiling was not optional as it couldn’t be held forgot long enough and lead to blurred features in the resulting photographs. This is why in most early photos people are not smiling and looking fairly sombre.
In this image, you can clearly see brush strokes enhancing furniture and clothing.
To correct the shortcomings of the early photographic process, photographers deployed a variety of techniques to enhance their photos. Ill-defined areas of detail, especially in the shadows, were enhanced with brush strokes of black ink, often painting in shadow lines around clothes or furniture. Eyes could be redrawn or lined in with pencil or even whitened with pigments similar to watercolours. Hairstyles could also be traced out with a careful brush stroke. I’ve seen images with a great deal of this enhancing and when restoring them there is no option but to leave it in. It not only adds to authenticity but if as it hides the true outlines, removing it would be detrimental to the image.