It wasn't at all unusual for small, local portrait studios to print using the direct contact method during the time in which Disfarmer worked from about 1915 until his death in 1959. Most small studios that concentrated on producing family portraits for the people living in the immediate area around the studio probably did not even have the needed enlarger to do the kinds of exposure manipulation - dodging, burning, unsharpen mask, etc. - that we associate with fine art techniques fully developed in the mid-20th century by photographers such as Ansel Adams, Edward Weston, and William Van Dyke in the western U.S. and by the developers at studios such as Magnum in the eastern U.S.
Another reason the use of enlargers wasn't popular in the very early days of photography was the lack of a suitable stable light source until proper electric bulbs were invented and the electrification needed to power them had spread across the landscape. Even the sun moves in the sky fast enough that a system of mirrors to constantly adjust for that movement was needed if sunlight was used to produce enlargements on the slow reacting papers of the time. If Heber Springs, Arkansas was like most typical towns in the American South, the rural areas weren't fully electrified until either just before or just after WWII. Since the negative sits directly over the printing paper for contact prints, the angle of the light used to expose the paper is much less critical.
Retouching certainly did go on at the time Defarmer began, but it was done directly to the negative before printing or sometimes to the finished print. Techniques including scraping with knives, drawing on top of the negative or print with graphite or ink, or even combining more than one negative either by placing one over the other or by cutting and pasting different parts of different negatives and attaching them together for making a contact print. With such techniques, contact prints from the altered negatives were still the main way prints were made.
What was unusual about Disfarmer's technical method was his use of glass plate negatives long after pretty much the rest of the world had moved to film for the type of work he was doing: taking portraits of the local inhabitants of the area surrounding his modest studio in Heber Springs, Arkansas. Large sheet film was introduced in 1913 and rapidly replaced glass plates for large format portraits, yet Disfarmer didn't finally switch over until near the very end of his career which lasted until his death in 1959.
When Disfarmer started around 1915, Ansel Adams was 13 years old. Willard Willard van Dyke was 9 years old and four years away from taking up photography. Weston was just beginning to make a name for himself after moving away from the large commercial studios in Los Angeles to open his own 'Little Studio' in Tropico, CA in 1910. He had just met Margrethe Mather, who was a major influence on Weston's style, sometime late in 1913.
Although retouching was already being practiced (that was what Weston was doing for a living in L.A. before he struck out on his own), outside of the major commerce centers of fine art photography in places such as New York, L.A., Chicago, etc. the use of enlargers wasn't that common.
The local portrait studios scattered in towns across the country were the "descendants" of the self-contained wagon studios that travelled the countryside in the mid to late 19th century. With wet collodion glass plates, the most common form of negative until the 1870s, the emulsion had to be mixed, spread on the glass plate, exposed, and developed within about 10 minutes. The primary skill set a potential photographer needed was the ability to quickly mix chemicals precisely and consistently each time a photo was taken so that the resulting emulsion had a predictable enough sensitivity that the exposure time would be correct.
But what has made prints of Mike Defarmer's portraits so desirable by collectors has very little if anything to do with his use of glass plates or of direct contact prints. What makes his work desireable is the entire story of how he came to make these photos and the way he made them without trying to pose his subjects the way most portraitists at the time did. As Michael Mattis, who is most responsible for the 'second revival" of interest in Defarmer's portraits, said years later:
... in my view, it is this unique insider/outsider mix, so evident in the pictures themselves, that is the essence of his genius, and the reason why - despite three decades of intense searching - no other studio photographer from that era has been uncovered whose accomplishment remotely matches Disfarmer's.
This is directly related to the entire mystique surrounding his self-instigated name change, the way he would carry his tripod around town while riding his horse wearing a Zorro-like cape (at a time when most people had long since moved from horseback to automobiles for personal transportation), and the way he would take the photo without warning his subjects or allowing them to pose first. It was probably also related to the fact that he was a bachelor, loner, atheist, and photographer in a small rural Arkansas town that had no other photographers, no other (publically acknowledged) atheists, and probably very few bachelors or anyone else that took being an eccentric loner to such extremes.
In an interview for the local newspaper (who printed it in the "Stranger than Fiction" section!) about why he changed his last name from Meyer to Disfarmer, he claimed that he was delivered to his parent's doorstep by a tornado. He also made it very clear that he changed his name because his surname at birth, Meyer/Meier/Meijer, was German for "dairy farmer" and he didn't want to be a farmer or associated with farming in any way. This he said in a small town in which just about everyone, including Disfarmer, made their living farming or by providing goods and services to farmers and their families!
Some of his clients described the experience of being photographed by Disfarmer as "very spooky and scary". He would disappear under the hood of his camera for long lengths of time and then suddenly take the photo without warning. "Instead of telling you to smile he just took the picture. No cheese or anything."