Mishnah Negaim 2:2: One may not examine Negaim [to check them] in the morning or towards evening, and not inside the house and not on the cloudy day, because the dull [Nega] seems bright [in these circumstances]. And [one may not examine] at noon, because the bright [Nega] seems dull. When does one examine? During the third, fourth, fifth, seventh, eighth and ninth [hours of the day]. These are the words of Rabbi Meir. Rabbi Yehudah says: During the fourth, fifth, eighth and ninth.

אֵין רוֹאִים הַנְּגָעִים בַּשַּׁחֲרִית וּבֵין הָעַרְבַּיִם, וְלֹא בְתוֹךְ הַבַּיִת, וְלֹא בַיּוֹם הַמְעֻנָּן, לְפִי שֶׁהַכֵּהָה נִרְאֵית עַזָּה. וְלֹא בַצָּהֳרַיִם, לְפִי שֶׁעַזָּה נִרְאֵית כֵּהָה. אֵימָתַי רוֹאִין. בְּשָׁלשׁ, בְּאַרְבַּע, וּבְחָמֵשׁ, וּבְשֶׁבַע, וּבִשְׁמֹנֶה, וּבְתֵשַׁע, דִּבְרֵי רַבִּי מֵאִיר. רַבִּי יְהוּדָה אוֹמֵר, בְּאַרְבַּע, בְּחָמֵשׁ, בִּשְׁמֹנֶה, וּבְתֵשַׁע:

Mishnah Negaim 2:3: A priest who is blind in one of his eyes, or whose brightness of vision dulled, may not examine the Negaim, as it says (Leviticus 13:12) "According to all that appears to the eyes of the priest." [When examining] a dark house, one does not open windows in it to [better] examine its Nega.

כֹּהֵן הַסּוּמָא בְאַחַת מֵעֵינָיו, אוֹ שֶׁכָּהָה מְאוֹר עֵינָיו, לֹא יִרְאֶה אֶת הַנְּגָעִים, שֶׁנֶּאֱמַר (ויקרא יג), לְכָל מַרְאֵה עֵינֵי הַכֹּהֵן. בַּיִת הָאָפֵל, אֵין פּוֹתְחִין בּוֹ חַלּוֹנוֹת לִרְאוֹת אֶת נִגְעוֹ: