Nyāya Sūtras 239.4

239.4

bāhyena prakāśenānugṛhītaṃ cakṣuḥ viṣayagrāhakaṃ tadabhāve 'nupalabdhiḥ/ sati ca prakāśānugrahe śītasparśopalabdhau ca satyāṃ tadāśrayasya dravyasya cakṣuṣā 'grahaṇaṃ rūpasyānudbhūtatvāt,

The eye grasps an object when assisted by external light; in the absence of that, there is non-apprehension. And even when there is assistance from light, and when cold touch is apprehended, the substance that is the substrate of that is not grasped by the eye, because [its] color is unmanifest.