Better "Aerochrome" (SD1) with red/yellow/orange filters

Started 3 months ago | Discussions thread
tagscuderia Senior Member • Posts: 1,894
Re: Better "Aerochrome" (SD1) with red/yellow/orange filters

HiddenRealms wrote:

Does the x3fworkshop work with the Sd1 files and is it still available online?

Ah, apparently not; you could PM ArvoJ (that's his username) and see if he'll send it to you. It 100% works with the SD1, just not with X3Fs that have been opened by SPP 6.x.x, thanks SIGMA!!

Lately, I‘m thinking about dual or even triple bandpass filters that block certain red/NIR portions... but honestly I have no idea if that would work...

It's worth thinking about how digital sensors and film differ, one is additive RGB and the other subtractive CMY. If this paper [Understanding Colour Infrared Photography] is correct, and there are some really helpful graphics, then it should give you a leg up on filters and matrices required e.g. car tail lights must reflect IR, twisting them to yellow. With Foveon's "green" layer being sensitive to IR, presumably you could create a matrix that reproduces that faithfully... it's beyond me though.


I also found my Foveon, B+W KB 20 spectral curves chart: RGB curves are the Foveon layers, KB 20 as labelled:

The Foveon layers are the spectral response sans hot mirror − if you visualise the effect of the KB 20 on each layer, the RAW composites make sense.

Same file as before, but this is a full RGB composite. The addition of the "Green" layer renders foliage as its opposite i.e. Magenta. The gain I think was: R-2.0; G-1.0; B1.0 and obviously changing those has a dramatic effect! Neither the yellow nor magenta version used 3x3 matrices.

Nick Spiker reverse engineered his own matrix, if you were able to do so (AND calculate the correct gain for your filter/s) then you could inject that into the X3F and continue using SPP. Otherwise you're delving into converting RAWs by hand; which trust me, is best avoided!

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