I just tried IR chrome effect

[Lou Jost]

15 minutes ago, ulf said:

What I miss from the IR Chrome is the darker sky, red tones turning yellow and the strange skin tones that are typical for Aerochrome too, beside the red foliage

I really want a filter that has no effect on visible colors, and just adds deep red for IR. IR Chrome comes close, after some manipulations, but without processing, the IR comes out as orange on  Sony cameras.

[Fedia]

I did a quick experiment to show how the color of the IR can be infuenced by the IR band that is allowed to pass.

 

all pictures taken on a Canon 1200D full spectrum with a 720nm filter on. White balance was done with this filter.

 

720nm image, white balanced :

 

Then I stacked different filters on top the 720. White balance settings are unchanged from the reference photo above.

 

720nm + GRB3 :

 

720nm + ZWB2 :

 

720nm + DB850 :

 

720nm + 850nm :

 

720nm + Hoya 80A :

 

We can observe the filters that pass shorter IR wavelength give a warmer color to the image (GRB3, ZWB2) than those which pass longer wavelength IR (DB850, 850nm) which in the contrary cool the image. Filters that reduce all IR wavelength evenly (Hoya 80A) don't influence color.

 

All this is to show that to get red trees SOOC (what the Irchrome aims for) it is probably more interesting to pass only the wavelenth that natively apear warmer to the camera and to exclude those which appear cooler.

 

This is why I think the Irchome mostly passes IR in the 700nm - 800nm region.

 

 

 

 

 

 

[Fedia]

1 hour ago, Lou Jost said:

I really want a filter that has no effect on visible colors, and just adds deep red for IR

 

The strong IR cutting of the Irchrome can seem counter-intuitive at first but it's necessary since the only way to preserve natural colors is to depolute from IR the channels which we don't want to record IR in. Reducing the IR transmition of the filter is the go to way to do so. Selecting the right band of IR as I mentioned on my previous post is another way to do it. To get the best result the two techniques can be used together.

[Lou Jost]

2 hours ago, Fedia said:

I did a quick experiment to show how the color of the IR can be infuenced by the IR band that is allowed to pass.

 

all pictures taken on a Canon 1200D full spectrum with a 720nm filter on. White balance was done with this filter.

 

720nm image, white balanced :

 

Then I stacked different filters on top the 720. White balance settings are unchanged from the reference photo above.

 

720nm + GRB3 :

 

720nm + ZWB2 :

 

720nm + DB850 :

 

720nm + 850nm :

 

720nm + Hoya 80A :

 

We can observe the filters that pass shorter IR wavelength give a warmer color to the image (GRB3, ZWB2) than those which pass longer wavelength IR (DB850, 850nm) which in the contrary cool the image. Filters that reduce all IR wavelength evenly (Hoya 80A) don't influence color.

 

All this is to show that to get red trees SOOC (what the Irchrome aims for) it is probably more interesting to pass only the wavelenth that natively apear warmer to the camera and to exclude those which appear cooler.

 

This is why I think the Irchome mostly passes IR in the 700nm - 800nm region.

 

 

 

 

 

 

That's a really good explanation, thank you.