Talk:Autochrome Lumière

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[edit] number of primaries

Copying this discussion here from my talk page. It was specifically about the primary color article, but is relevant here. -- jacobolus

Hi, thanks for keeping on top of changes there; just curious about your comment:

no, autochrome didn't use 6 primaries

From the autochrome article it sounds as though the patent certainly describes six (possibly more)?

quota 17:36, 15 August 2007 (UTC)

OK if I butt in here? See the patent. I think the article needs to be amended and this patent cited. It says one layer of three (or optionally more) colors, I think, though I haven't read it all carefully yet. Dicklyon 21:21, 15 August 2007 (UTC)

Thanks for finding the patent! I'll add it to the Autochrome article, which also definitely needs an update. The patent clearly says "They are colored by means of colors also transparent in orange, green, and violet, or else in red, yellow, and blue, or even in any number of colors." -- so Primary Color needs a bit of clarification, too. I'll have a go... quota 07:32, 16 August 2007 (UTC)

Thanks for tracking that down Dicklyon! It looks to me like the patent tries to be broad, but most (perhaps all) actual use of Autochrome was with three primaries, though the exact color could vary. But maybe I'm reading that wrong? --jacobolus (t) 00:07, 17 August 2007 (UTC)

Patents are written as broadly as possible. Everything I've read on the actual autochrome plates says orange, green, and violet. Dicklyon 01:34, 17 August 2007 (UTC)

Kudos for finding the patent. When I copyedited this a while ago I realised the ref to six primaries was wrong (the original edit almost certainly referred to the resulting (secondary) colours when two primary coloured grains overlapped) but couldn't find the patent to disprove it. Good call. mikaul^talk 13:59, 17 August 2007 (UTC)

Right, exactly. :) --jacobolus (t) 23:13, 17 August 2007 (UTC)