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UltravioletPhotography

Kolarivision IR Chrome 'Aerochrome' filter


GaryR

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Well, we knew from the first examples that Yann posted on various sites and Kolari site that it was not actual EIR transposition. There is no way it could be without post processing.

So don't expect yellow from red.

The idea behind this and other stacks like the 729 stack is simply to suppress visual red, and leave the visual red Bayer open to IR only, and preferably the lower IR range which has a higher Bayer sensitivity to red

(thus the use of KG3 for attenuating the IR range to the lower part of the IR range).

Unfortunately, the Hoya B-410 doesn't suppress red enough to remove it entirely. Thus the red channel is still a mix or visual red and not suppressed in the correct range to remove everything.

729 works better for that.

Whatever someone is doing to make the IR Chrome look red instead of orange is not yet known to me, and not yet explained on this board.

If there is a method for making that happen, it seems like it would behoove whoever to instruct.

I mean this with no disrespect, it would simply be very good information for all those who have purchased the filter thinking they can produce the red examples they have seen posted.

I would buy one myself, if I thought it would work. But I have B-410, and I think this is a B-140 stack, and I have never been able to make B-410 look really red.

So far, I have seen no one who purchased the IR Chome show any examples that look red.

And Birna even, and Birna knows some stuff...

 

Hi Cadmium,

 

Indeed, EIR exact transposition cannot be done with a RGB sensor, it's far too different from how the color film worked. It's an "emulation" a "re-creation" but not an exact copy : Kodak's mastery cannot be replicated unless we build a sensor specifically for with a designated channel for infrareds.

Again the key to obtain RED leaves with IRChrome lies in 2 factors :

• White balance. If not done correctly it usually shifts towards orange

• Sensor manufacturer : Canon is the best to obtain in-camera reds without doing adjustments in post. But when using Nikon or Sony, orange is common and the WB should be shifted accordingly. As mentionned on Kolari's website and in the presentation video : RAW development is mandatory to obtain an Aerochromesque render. That means : white balance, grain, contrast... everything that you do when opening a RAW file. If you want an absolutely exact replica of EIR without doing any post, it's almost impossible with actual sensor technology. Of course there are filtering combinations that works more accurately (Scuba+KG3, etc) but either can't be glass-manufactured or affects shutter speed too much.

 

To have a move RED effect directly in sensor, you can stack some light yellow filter (like GG435 UV suppressing, or NKIR Y03, but again I tested this only in Canon and using other brands could be disappointing ! The different sensors make a HUGE shift in infrared outcomes). Or you can WB not on grey but a warm grey (either reddish or orangeish).

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So far I have not seen red from anyone using it except you. Everyone else shows orange.

That's what happens with B-410 stacks for me.

I'm not the only one ;)

These are certainly processed images but there are as many orangeish as reddish IRChrome-shot pictures : https://www.instagram.com/explore/tags/irchrome

I don't know which exact glass was used by KV. I only handed them the transmission curves I crafted. As it's now US-manufactured, it's certainly not B-410. But indeed it seems close to what you show.

Every other glass-made cyan/blue filters gives results that are even more far from red hues : QB4, QB19, ZWB3; etc...

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There are Chinese equivalents to B-410. :smile:

Yes for sure, but I'm certainly not an expert in glass manufacturing/trading. You know all the sorts available far better than me ! :-) Problem with a lot of Chinese glass is consistency in all the batches made. If it's for light color filtering that doesn't matter a lot but for photography and especially multrispectral imaging, it matters a lot more !

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  • 2 months later...

Cadmium writes: I would buy one myself, if I thought it would work. But I have B-410, and I think this is a B-140 stack, and I have never been able to make B-410 look really red.

 

Attached is a repeat of a B-410 photo. Is this "really red"? I can make it redder a different red.

And here is how I Turned Orange into Red: Hoya B-410 Red Blocker --> EIR: Photo Ninja Tutorial

I put this photo into Photoshop Elements and clicked around in the red with the dropper.

I saw readings of 1°, 3°, 6°, 358°, etc. So this is definitely Red.

 

 

lochbroomb410.jpg

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Cadmium, I have with total respect "borrowed" this image to illustrate turning orange to red for a B-410.

 

 

Using Capture NX2, put one color point on the orange and turn the colour wheel from orange to red. The small orange square in the Color Picker shows the original orange. The large square shows the new Red.

It only takes an approximate 15° turn of the color wheel.

Of course this method is sadly archaic since nobody can use NX2 any more unless they have a very old operating system. So now I have to use Photo Ninja for this.

Screen Shot 2020-01-07 at 12.59.42 PM.jpg

 

 

cadmium.jpg

 

 

It took two trips thru Photo Ninja to get this version.

(I worked too fast and oversaturated the red which wrecked some detail. Sorry 'bout that.)

((And I oversaturated the green. Geez, Andrea, you are heavy handed today.))

cadorigpnpn.jpg

 

 

The point of the preceding tweak is to point out that the B-410 orange is only about 15° off of Red. So it only takes a minor tweak to turn B-410 Orange to Red. I don't currently have a channel mixer, but that could also be used. The easiest ever method was the NX2 color point. I think color points live on in a DxO app, but I don't have that so am learning other methods now.

 


To be sure, I do understand the desire to have the Aerochrome look arrive already red & blue SOOC.

 


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Are you 'being bad' today, Andrea? :wink:

https://www.ultravio...__fromsearch__1

 

YIKES!!! To me it looks like someone tweaked it. I little unnatural. It looks over saturated, kind of like spray paint. Seriously.

I am trying to figure out which one of my photo you used for that tweak?

 

OK, I found the one you used.

Here is the original Hoya B-410 2mm + KG3 2mm stack shot.

post-87-0-69955000-1578434523.jpg

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Yes, Cadmium I was very bad. But people keep doing this. So I've kind of given up. It is probably not something I need to be worrying about given the multitude of other chores I'm behind on getting done for UVP. I'll probably remove that "forum courtesy" post. We need to promote experimentation here on UVP so that we all learn.

*****

 

Yes, of course, the red shifted photo looks spray-painted. The color shift and saturation shift were done on a resized JPG. That is guaranteed to destroy some detail! This does not happen if the tweaks are applied to a raw file where you can control things better. You can see that in the tutorial.

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