Do you know the wavelength of your UV light? If your lows aren't getting dark enough in such a long time, it might indicate your UV light's wavelength isn't optimal. 365nm is supposedly best, but I found it harder to find decent options. So mine are 385nm (40W) and 395nm (200W) and the corresponding exposure times and distances are only: ~1:45min (4 inch) and ~2:40min (16-20 inch). For the latter, I initially also used a sheet of paper to diffuse the light more (for larger prints), but that extended the exposure time to ~17mins for not any noticeable difference...
(Btw. This is all for kallitype, but should equally apply for salt)
#AltProcess #Kallitype #SaltPrint #UVLight
Karsten Schmidt
npub1lf…s5lyy
2026-05-05 08:24:00 UTC
in reply to nevent1q…0209
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npub1lfn827aqxvg9gxel64vxnpjkkundr0khkeh568asjp6qft8csd0ses5lyyPublished at
2026-05-05 08:24:00 UTCEvent JSON
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"content": "Do you know the wavelength of your UV light? If your lows aren't getting dark enough in such a long time, it might indicate your UV light's wavelength isn't optimal. 365nm is supposedly best, but I found it harder to find decent options. So mine are 385nm (40W) and 395nm (200W) and the corresponding exposure times and distances are only: ~1:45min (4 inch) and ~2:40min (16-20 inch). For the latter, I initially also used a sheet of paper to diffuse the light more (for larger prints), but that extended the exposure time to ~17mins for not any noticeable difference...\n\n(Btw. This is all for kallitype, but should equally apply for salt)\n\n#AltProcess #Kallitype #SaltPrint #UVLight",
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