Getting grass color right

[Digitizer]

Okay, let’s see what I understand from the thread (about oversaturated greens) you linked to in relation to what I read in your post(s)

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@davidS

One thought. I have not found specs for the Keiser light source but am guessing that it uses white LED’s. I would love to see a scan of the same negative using a phone or an iPad for your backlight.

The Kaiser has white LED indeed and there is a post about using an iPad as backlight, albeit in a slightly unusual way.

Scanning Colour Negatives With a Monochrome Camera

This is just a proof of concept. Owners of monochrome cameras like a Phase One or Leica might profit from it. The process consumes a bit more time than simply using Negative Lab Pro, which is not needed for it anyway. In order to get some extra hurdles, I tried the process using my worst lit (mixed low light, underexposed) negative. [Bildschirmfoto 2020-06-23 um 12.40.29] I used/did the following items/things iPad as a backlight - with three images, one red, one green, one blue Camera scan…

Making the backlight “monochromatic” helps in this special experiment, but it does not add any magic in all other cases as far as I’ve tested. BTW, I later ran the test with the CMY backlights - basically a waste of time in a RGB world.

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More about separating r, g and b in a backlight:

chris’ answer to pehar’s post from the thread you linked to.

[quote=“pehar, post:14, topic:20293”]
having a CRI of > 95 Ra. This gives me an excellent base to get natural looking colors after inversion and compensation of the orange mask
[/quote]

Now I am a bit confused. From the parallel thread I thought I learned that an illumination at 3 distinct wavelengths would be much better for negatives as the orange mask would not spill into red and green. Now a high-cri spectrum (i.e., more white, including orange) gives better results. Confusing. Any thoughts?

In a model world, red, green and blue would be “pure” colours and our eyes and camera sensors would exactly see just that: red green and blue. In the real world, our brain recognises something as red, green or blue (or yellow or cyan etc.) because our eyes get overlapping colour information from whatever they see. The same goes for camera sensors, here’s an example of how they separate colours:

Our brain relies on (has to cope with) overlapping colour information and so does the firmware in digital cameras. Take away all the light hues that are not r, g or b - and get a completely new world of colour vision. Even in a digital world, there are infinite shades of grey or colour between black and white. It’s mostly politicians who manage to reduce our world to either-or.

To make a long thing short:

• get a high CRI backlight and work with it (best practice as accepted in this forum)
• or try whatever alternative you deem promising and let us know, what your findings are