Ottoman Historical Fashion recommendations & a contemporary account dating 1599 translated into Modern English— my translation:
Jennifer M. Scarce's “Women's Costume of the Near and Middle East”
Kass McGann's Ottoman Turkish Women's Getting Dressed Guide: Dress in the Golden Age — 1520-1683 (illustrated by Robert P. Davis)
Ottoman (mostly) men's fashion: a reproduction of a contemporary book
The visual depiction of the following account is from this (otherwise quite outdated but very interesting) documentary at the 3:08 - 4:08 mark.
A 1599 account (featured in “Early Voyages and Travels in the Levant”) by an English technician, Thomas Dallam recalled the sight of thirty concubines that he spied (through a grate of very thick harem walls grated on both sides with iron very strongly) while they were playing with a ball. Anyways, I have translated this account into Modern English:
“Then he [likely one of the black eunuchs, Kizlar Ağa?] showed me many other things which I wondered at, then crossing through a little square court paved with marble, he pointed me to go to a grate in a wall, but made me a sign that he might not go thither himself.
When I came to the grate the wall was very thick, and grated on both the sides with iron very strongly; but through that grate I did see thirty of the Grand Signior's concubines that were playing with a ball in another court.
At the first sight of them I thought they had been young men, but when I saw the hair of their heads hang down on their backs, plaited together with a tassel of small pearl hanging in the lower end of it, and by other plain tokens, I did know them to be women, and very pretty ones indeed.
They wore upon their heads nothing but a little cap of cloth of gold, which only covered the crown of their heads, no bands about their necks, nor anything but fair chains of pearls and a jewel hanging on their breasts and jewels on their ears;
Their coats were like a soldier’s mandilion [a buttoned cloak], some of red satin and some of blue, and some of other colours, and girded like a lace of contrasting colours; they wore breeches [i.e., trousers or pants] of [scamatie, wool essentially], fine cloth made of cotton wool, as white as snow and as fine as muslin, for I could discern the skin of their thighs through it.
These breeches came down to their midleg; some of them did wear fine cordovan buskins, and some had their legs naked, with a gold ring on the small of their leg; on their foot a velvet pantoble [shoe] 4 or 5 inches high.
I stood so long looking upon them that he who had showed me all this kindness began to be very angry with me. He made a wry mouth, and stamped with his foot to make me stop looking; I had loathed to bow, for that sight did please me wondrously well.
Then I went away with this Jemoglane to the place where we left my dragoman or interpreter, and I told my interpreter that I had seen 30 of the Grand Signor's concubines; but my interpreter advised me that by no means I should speak of it, whereby any Turk might hear of it; for if it were known to some Turks, it would present death to him that showed them to me. He dared not look upon them himself.
Although I looked so long upon them, they did not see me, nor all that while looked towards that place. If they had seen me, they would all have come presently thither to look upon me, and have wondered as much at me, or how I came thither, as I did to see them.”
Essentially, this guy was here because the English Queen Elizabeth I (r. 1558-1603) and Safiye Sultan, the wife of Murad III (r. 1574-95) and the mother of Mehmed III (r. 1595-1603) shared a very good epistolary relationship about which on the r/sultanateofwomen had been posted about too, here, and Elizabeth and Safiye exchanged gifts too— at this time Elizabeth sent an organ to Safiye (now she was Queen Mother), but of course, the Ottomans presumably won't know how to install it, so the Tudor Queen had sent this guy to install it and Safiye sent him to just at the boundary of the actual harem to get it installed.
He didn't "enter" the harem, he was "outside" in another court and merely watched the 30 concubines through a very thick and strongly ironed grate while they're playing with a ball— and like he himself said in the last para, the women didn't see him.
(Fwiw, later Ahmed I, Mehmed's successor had Safiye's organ broken because he was a very conservative guy and didn't like Western "infidel" stuff at the Ottoman court...)