This is a question with both a relatively straightforward answer and a healthy amount of speculation. Generally, the answer depends on the period you’re considering and we have to take some examples with a grain of salt due to the absence of ‘unbiased’ evidence. I’m going to start with a couple of particularly notable examples from the fifteenth and sixteenth century and then move into the mid-nineteenth century where we can directly compare portraits and daguerreotypes.

Important to consider are the traditional conventions of portrait painting (and I really should mention here that I’m thinking specifically about Western conventions. The East, particularly early Chinese photography, has its own distinct history that I’m less familiar with given my expertise in nineteenth century American art, so I’ll limit my answer to the West and hope that somebody else chimes in). Portraiture in medieval, renaissance, and early modern West is nominally about who the portrait depicts and forwarding a reasonably accurate image of a real person, but the real pith lies in what I’m going to obliquely refer to as ‘portraiture conventions.’ Those conventions involve the iconography of objects, particular poses that often reference surviving Classic works, and even more esoteric elements (particularly towards the nineteenth century) like the size, shape, and lighting of foreheads (more on that later).^1

Let’s start briefly with Jan van Eyck’s Arnolfini Portrait(https://upload.wikimedia.org/wikipedia/commons/thumb/3/33/Van_Eyck_-Arnolfini_Portrait.jpg/300px-Van_Eyck-_Arnolfini_Portrait.jpg) a very famous and tediously examined painting. It’s been called alternatively the Arnolfini Portrait (the name it’s most typically referred to by today) theArnolfini Wedding, Double Portrait of Giovanni Arnolfini and his bride, and still others. Panofsky alleged this painting functioned as a marriage contract, essentially a visual witness to the marriage between a prominent Venetian merchant and his new wife. More recent scholarship, notably Margaret Koster’s 2003 article in Apollo, has asserted that this was a painting of mourning, a memento commissioned by Arnolfini to mourn the untimely death of his wife, Costanza. If you want to really dig in, there’s extensive scholarship analyzing the dog (an apparent signifier of fidelity), the mirror, the sumptuous cloth that Arnolfini may have traded in, and many references to fertility through the woman’s pose and her folding of the cloth, and most of the other details you can imagine. This is all to hopefully emphasize that early portraiture is about creating an idealized and, in some cases, didactic image, not about trying to paint a figure as realistically as possible. We obviously don’t have photographs of the Arnolfinis, nor do we have physical descriptions. So I can’t tell you that van Eyck omitted a pimple here or a freckle there. We can hypothesize that, even for the wealthy, the fifteenth century was a rougher time and it might be outrageous to expect that a middle-aged man and his wife would have pristine, unblemished skin, but I can’t point to any document that references arnolifini’s acne or lack thereof. Suffice to say that portraiture was deeply imbricated with the imagination it allowed for, in projecting a subject not necessarily as they are, but how they want to be seen. In the world of photography, this becomes perhaps less feasible.

Any discussion of realistic conventions in portraiture wouldn’t be complete without a brief mention of the Habsburgs. The Habsburgs today are most famous for both their dynastic rule of much of Europe and their notorious inbreeding that, among other things, created some rather striking and unusual physical features.

Compare this description of characteristic Habsburg facial features from a 1988 journal article:

“Prognathism, a thick, everted lower lip, large, often misshapen nose with a prominent dorsal hump, a tendency of flattening of the malar areas, and mild eversion of the lower eyelids”^2.

to this portrait of Charles V, arguably the most severely affected of the dynasty, by the Venetian master, Titian. Notice that Titian here is directing you less towards his face and more towards the grand armor, powerful pose, and liberal use of a red lake pigment that scholars today often refer to as ‘Titian Red’ that had particularly sumptuous associations. The pose itself recalls the Equestrian Statue of Marcus Aurelius, which would’ve carried loaded associations. Other portraits were perhaps less flattering, but still no match for the description we read above.

Now, let’s take a look at a particular nineteenth century American artist whose career overlapped with the invention of the Daguerrotype: Thomas Cole. Cole, the preeminent American landscape painter of the early Hudson River School, was in his late thirties when the daguerrotype was invented and he was, at least according to his journal and a few letters, an early proponent of the medium. Let’s compare two portraits, the first by Cole’s friend Asher B. Durand and the second a self-portrait to a daguerrotype of Cole. The daguerrotype was taken a little later than the portraits were created, towards the end of Cole’s life (he died just after turning 47) and possibly while his health was beginning to fail, though the pleurisy that killed him was reportedly rapid and unexpected. The different depictions all clearly resemble each other, but the painted portraits do seem much more idealized, painting a picture of a more vivacious man and one with a fuller head of hair. The painted portraits also allow each artist to place particular emphasis on Cole’s robust forehead, a reference to contemporary phrenology that held that a prominent forehead was associated with genius. So while the portraits don’t radically change Cole’s appearance, subtle tweaks idealize him and bring to the forefront associations that the artists wanted audiences to make with Cole that might not be immediately apparent in photography.

Portraiture historically is most often about power and communicating an idealized vision of a sitter meant to reflect their authority or important associations. But compare that to the portraiture conventions of today and it might not seem all that different. We use photoshop, props, magnificent vistas or popular attractions, even other people to idealize the subjects of photography today. Different conventions of idealization, from a permanently youthful and physically vivacious countenance to the wisened, wrinkled visages of Roman verist busts; from prominent foreheads to digitally-slimmed waists, have risen and fallen in popularity over the millennia. It seems that regardless of the style or technology, people have long sought to idealize themselves in their representations.

——————————————————————— Notes

1. When referencing iconography, I’m thinking specifically in the Panofskian sense of iconology. This is an art historical practice of identifying objects, symbols, and the like in a painting and tracing the associations it would’ve had to a contemporary audience. Panofsky is still foundational to the field of art history, but recently has drawn criticism for the specificity of iconology to Dutch renaissance painting and apparent logical leaps he’s made.

2. EM Thompson and RM Winter, ‘Another family with the ‘Habsburg Jaw’’ Journal of Medical Genetics 25, 1988, 838-9

Other sources:

Panofsky, Erwin, "Jan van Eyck's Arnolfini Portrait", The Burlington Magazine for Connoisseurs, volume 64, issue 372, pages 117–119 + 122–127, March 1934

Koster, Margaret L., "The Arnolfini double portrait: a simple solution", Apollo, volume 158, issue 499, pages 3–14, September 2003

Most of the Cole information has been culled from primary sources available in print at the New York State Library, Albany Institute of History and Art, Detroit Institute of Art, and the Thomas Cole National Historic Site. Information about Cole’s relationship to the daguerrotype can be found in a recent catalogue (Shi Guorui: Ab/Sense Pre/Sense) published by the Thomas Cole National Historic Site. Generally, an exchange of letters between Cole and his old friend William Bayless of Ohio discuss the daguerrotype at length and positively. The letters to Bayless can be found at the NYSL, along with his 1834-48 Journal, ‘Thoughts and Occurrences,’ which also has an uncharacteristically lengthy entry discussing the daguerrotype. This entry alludes to Cole’s anxiety about the new medium, understandably as it posed a threat to his livelihood of landscape painting, while also being cautiously optimistic about how it might challenge his contemporaries to be more accurate and exacting and indeed heighten the field of painting. There’s a whole other askhistorians post for Cole’s diaries, or really anything Cole, but I’ll leave it at that.

I’ve never answered one of these, so hopefully it wasn’t too bad!