Well this has been brought up on this sub more than once, and is a tricky question for a number of reasons, not least of which being that your hypothetical Egyptian would not have been perceiving skin tone using the same metric of race/skin pigment that seems ubiquitous in modern times. Beyond even this, the overall cultural values assigned to skin tone might not be the same depending on that Egyptian's cultural background.

Race in the modern sense of the word has no direct equivalency in Antiquity so we can say that they would not have perceived any kind of binary categorization of race at all in a manner recognisable to us. Ethnicity is another matter entirely and was a central aspect of identity formation in Hellenistic and Roman Egypt but that was not centred around skin tone, it was primarily dictated by cultural background and ancestry (and actually, ancestry was disregarded in many respects in favour of social standing). For instance, in the 2nd Century BCE, a Macedonian settler would not have viewed themselves as being the same as an Egyptian but they would also have seen themselves fundamentally different than a Galatian regardless of whether they themselves were of swarthier complexion or fair haired and light-eyed because the idea of an identity centred around Europeanness, or whiteness/blackness did not exist. This is worth keeping in mind when considering the otherisation of foreign peoples in ancient sources, as it can be easy for us to project preconceived notions about where their inherent biases stem from without regard for the differences in their world-view. So while Greek (and later Roman) writings might speak of the savagery of distant Ethiopians and Celts this was not based on a dichotomy of white/non-white or European/African but on peoples geographic and cultural distance from what they considered the epicenter of the civilised world.

Even in physical descriptions of individuals, ancient authors were not overly preoccupied with the skin tone of their subjects unless they were specifically trying to point out something of note by it, and terms sometimes, used to describe skin colour could also be used interchangeably to describe hair making it not always apparent whether and individual is being described as fair or blonde, dark skinned or dark haired.

So to look at the various possibilities for this question we will look at how New Kingdom Egyptians, Hellenistic Greeks, and Romans perceived differences in skin tone before tying it into Hellenistic Egyptian culture.

When looking at Egyptian art from the Old Kingdom to the Roman period what stands out about depictions of Egyptians is the polarity of skin tones between genders. Males are often depicted with dark reddish brown skin while women are nearly always light skinned which is more a stylistic choice intended to convey a masculine/feminine dichotomy than any kind of naturalistic observation. Greek and Roman authors noted that there were variances between the peoples living on the Nile with the people to the north being fairer than those in the south as the population grew darker the further up the Nile one travelled which meshes fairly well with estimations of the demographics of ancient Egypt and with the realities of modern Egypt. In early Egyptian art Asiatics and Nubians on the other hand are often depicted in stereotypical vignettes which unmistakably convey their origin in scenes portraying them being defeated in battle or diplomatic ventures but beyond typified depictions there is no significant caricaturisation. Beyond this, Nubians came to make up a sizeable portion of the army and police force from the Middle Kingdom onwards as a result of Egypt's increasing control over the southern cataracts, as well as seeming to have integrated into Egyptian society in general. There does not appear to have been any kind of racial hierarchy based on skin tone and although Egyptians looked down on their neighbours to the south they were equally prejudiced to their Aegean and Levantine contacts.

Of course, we might assume that living in Alexandria they will be Hellenized, even though there is plenty of evidence of upper class Egyptians who interacted with Hellenes in the poleis or the Ptolemaic administration without any significant apparent acquisition of Greek culture, and at times even Greek language.

Neither the Greeks or Romans attached preconceived notions or cultural values to skin tone or held modern prejudices around race although they were starkly aware of differences in appearances between peoples. Climate and geography was generally considered to have impacted the physical characteristics and culture with colder, moister regions producing men who were fairer, larger, longer lived and more courageous but hot, arid climates producing darker people who were quicker in body and mind but less disposed towards more masculine virtues. Celtic, Scythian and Germanic peoples representing one extreme from Hellenes or Romans, and Ethiopians and Libyans the other. As Hippocrates observed in Airs, Waters and Places

As the other Scythians have a peculiarity of shape, and do not resemble any other, the same observation applies to the Egyptians, only that the latter are oppressed by heat and the former by cold.

That said, most distinctions were not based on skin tone but the region and culture that the individual came from and even this was not a fixed construct that determined individual temperament like modern racism or ethnocentrism, with a greater emphasis being placed on the free/slave dichotomy or individual merit. Although there are some anecdotes such as Septimius Severus' dismissal of an Ethiopian soldier he encountered in Britain as an ominous portent it is unlikely that individuals who were accustomed to seeing very dark skinned individuals would have felt such a way, in fact Agatharchides writing from 2nd Century BCE Alexandria states that such a superstition around Ethiopians was not something a Greek would put much stock in after childhood. Ethiopians are generally linked to dark skin in Greek and Roman writings with it sometimes acting as a catch-all term for Africans that were neither Egyptian or Libyan and there are plenty of references and depictions of white or light-skinned Ethiopians like most images of the mythological Andromeda, undermine assumption that this was a category defined by colour. It was also recognized that dark skinned peoples came from Asia, and India in particular, who are also often described as Ethiopians or vice versa. Similarly, Mauretania was located in North Africa, but Mauri were not generally considered Ethiopian although they may occasionally be referenced or compared to Ethiopians in the manner of Indians. For instance the epigrammatic poet Philodemus references "Indian Andromeda"

If she is Italian and her name is Flora and she does not sing Sappho, yet Perseus was in love with Indian Andromeda.

Indian Andromeda is referenced more than once in Roman poetry as Andromeda was the Ethiopian princess Perseus saved from the Kraken. It is worth noting that writers did distinguish between the appearances of dark peoples from Ethiopia, Libya and India both in variances in tone, facial features and hair types so colour was not the only or even primary means of differentiation at work. Aethiop itself is a reference to burnt or dark skin, but the term seems to have become somewhat malleable with time being applied to dark Asiatics and light Africans, in general however, it applied to darker peoples in Northern Africa such as those on the Ethiopian coast and Nubia with other uses being comparative.

One thing of interest is how differences in appearance might have been explained or rationalised.

The only explanations from Egyptian literature I know of attributed it to the whim of the creator but I would be interested to know of any less well known archaic references to the origin of peoples differing appearances in Egyptian myth.

In Greek literature there are examples of both mythological and scientific explanations, some of which may have been more popular than others, like the environmental theory which is most widely discussed today. Ovid in his Metamorphoses cites Phaethon's failed attempt to drive his father Apollo's chariot, in which he scorched the earth and Jupiter was forced to strike the chariot down, as the reason for the darkness of their skin

It was then, so they believe, that the Ethiopians acquired their dark colour, since the blood was drawn to the surface of their bodies.

Herodotus recounts an environmental theory when discussing the Ethiopians

And thirdly, the men of the country are black because of the heat.

Continued --->