Help needed with IR chrome data

[Namestom]

Can anyone provide me some data in the IRChrome? I need someone to balance exposure on the blue sky(or something that is the same color blue) without the filter on, then put the filter on and change only the SS to balance the exposure value. Then repeat this on foliage(or any other source of infrared light). I'd need the meta data(aperture, SS, ISO). I'm going to calculate the exposure compensation and using all my data provide a Transmittance chart(it would be a best estimate, not 100% factual).

[dabateman]

To get the best out of IRchrome filter set, the White balance also is critical. Can be hard to nail that.

I don't have much trees around but could try this with my lee 729 + Kg3 or GRB3 Chinese stack.

[Andrea B.]

Which exactly is IRChrome?

If I have it, I'm happy to do this for you.

 

I searched on the term IRChrome, but didn't find anything. I'm assuming we are talking about a kind of AeroChrome filtration with the red trees, etc. ???

 

Duh! See next post.

[Andrea B.]

Oh, nevermind the preceding stoopid question. I found it in a larger search. You are referring to the Kolari IR Chrome filter.

 

I have the B-410 for this, but I don't have any K glass to make the stack. I'll check with Cadmium to see about getting some. Or I suppose I could just get the IR Chrome.

[Cadmium]

Don't assume that IR Chrome is the same as B-410 + KG3 just because I think it is.

In fact, I know it isn't the exact same thing.

IR Chrome is two 1mm thick glass filters glued together. 2mm thick, total.

So in that aspect it is not exactly the same as B-410 2mm + KG3 2mm.

Does it work the same? Does it look the same when individually white balanced on a gray card, for the same scene, at the same time?

That remains to be tested.

But everyone I have seen post examples of the IR Chrome shows orange foliage, and that is why I say it looks like a B-410 stack.

I have Birna's copy now, and when I get around to it, I will pair it up with a B-410 stack and do a fair test comparison, see how close they look.

[Andrea B.]

The real question is what colour are the IR Chrome trees when the file is converted in Raw Digger ?

That would tell you how to best set your in-camera WB to promote red or, alternately, how best to process the raw file to get red.

[Cadmium]

From my experience with these types of filters, it is best to set the white balance in camera from a gray card.

Any attempt I have made white balancing them from RAW has not looked as good as from a gray card in camera.

Maybe get a RAW file from someone who has those filters, and play with them in Digger.

Here is a pic of the 729 stack white balanced from a gray card in camera, easy to do.

 

[Cadmium]

By the way, here is a photo of IR Chrome and B-410 2mm + KG3 2mm stack, just give you an idea how close they are in color, visually, to the eye.to compare the visual color to eye.

Which is which?

I am not implying these are the same, and I know they are not constructed the same, I am only showing a visual color comparison of the filter glass.

Maybe sometime i will see the sun again...

 

[dabateman]

The one on the left is IRchrome.

It looks a lot like Lee 183.

 

[Cadmium]

Lee 183 + KG3 2mm, white balanced in camera from gray card.

Red or orange?

 

 

[bobfriedman]

my B-410 shot

 

Nikon D800 ,AF-S NIKKOR 16-35mm f/4G ED VR ,B-410

1/200s f/8.0 at 16.0mm iso10

[dabateman]

Lee 183 + KG3 2mm, white balanced in camera from gray card.

Red or orange?

 

 

 

When the sun returns Cadmium, set white balance using the suba lee 729 + Kg3 filter. Then use the exact same wb preset for the Lee 183 +Kg3 filter and it will look the same with better exposure.

 

[Namestom]

It's all about complimentary colors. To white balance out the main color of the filter, all the colors shift towards the complementary color. Blue would shift to orange/red. But your camera actually sees the majority of IR as magenta which then shifts the IR closer to red. Then with a balance of slightly more IR then Blue light, you get oversaturated red(slightly orange). When the actual light entering the camera cant be white balanced because of the off balance of IR and Blue light entering, you get different or off colors. This also happens with a bad white balance, you get slightly more orange foliage. White balamcd is so important! Your tricking your camera into making IR light into a visual color. Once its recorded there is nothing to change it really. Software cant differentiate ir from all the other colors. Cyan is the complimentary color to red. A balanced cyan filter would give a red(slightly purple) foliage due to the orginal magenta color. Wratten #44 is perfect. I'm also looking at cokin 050(resin) and got the transmission graph for it.

With the data I have about IRchrome is that the color is blue/slightly cyan and it let's in ir from 700 to 850nm. The filter is supposedly fused together.

[Cadmium]

"Fused" mean glued. It is glued. Adhesive, laminated, call it what you will, but the glass is not melted together (fused), it is glued.

 

The problem with the graph above is one of the problems with B-410 also, it transmits red. You don't want the filter to transmit ANYTHING between about 560nm and 720nm.

If it does, then you can white balance it any which way and it will look orange.

For those of you who haven't tried 729, you might do that sometime and compare.

White balance each compared filter in cam with gray card, then shoot each with individual white balance.

Compare 729.

Let me know if you find something more red.

And show what you think with a test.

[Cadmium]

Here I have scraped a little of the glue with my X-acto knife from between the two pieces of glass.

That is glue. It is glued, or if you want to call it 'fused' then fine, but know that it is 'fused' with glue.

I use to hang around with a lot of glass artists that made fused glass items by stacking layers of glass and melting them together in a kiln, so to me "fused" means melted together.

This filter can be separated with solvents. You can't do that with fused glass.

There is nothing wrong with glue, that is how filter stacks are made.

 

 

[Namestom]

"Fused" mean glued. It is glued. Adhesive, laminated, call it what you will, but the glass is not melted together (fused), it is glued.

 

The problem with the graph above is one of the problems with B-410 also, it transmits red. You don't want the filter to transmit ANYTHING between about 560nm and 720nm.

If it does, then you can white balance it any which way and it will look orange.

For those of you who haven't tried 729, you might do that sometime and compare.

White balance each compared filter in cam with gray card, then shoot each with individual white balance.

Compare 729.

Let me know if you find something more red.

And show what you think with a test.

The two neewer filters do not transmit any red at all. I suspect IRChrome does either. It's more about the glass color to me. I agree any red/orange, would greatly throw off the colors. The cokin 050 let's in a ton of light compared to Lee 729. I'm going to try it with an ND filter for sure. I have both that pass IR and surpress IR. I'm thinking the high Transmittance of it might mean red at 20% wont even be exposed. The IRchrome in my opinion is going to come out as cheap glass, and nothing special. Why else would you not post a Transmittance graph and glue the layers together?

[Cadmium]

Have you ever tried 729? It is pretty inexpensive for sure. It is dark, it requires longer exposures, than others, but works just fine hand held, no problems.

It is more red than others. Everything else I have tried is more orange.

 

Maybe you mean 'they' when you say 'you'? In that case, then the reason is because 'they' don't want to reveal technical details about a filter to people,

it might help people duplicate the recipe, it destroys the mystery, and mystery sells.

Many filter companies don't show any graphs for their filters, which always annoys me, but people fall in love with the mystery.

 

I am not sure I understand your question about gluing the layers together. There is nothing wrong with gluing filter glass together, that is how combined transmission is made.

There are many filter stacks that produce special transmissions when stacked (and/or glued) that no single filter can produce on its own, unless some special dichroic filter were designed to so something similar,

and that is not always the best way to go either.

Gluing layers of filter glass together is perfectly normal. Calling that 'fused' seems to imply something that is melted together.

It isn't important.

[Namestom]

Have you ever tried 729? It is pretty inexpensive for sure. It is dark, it requires longer exposures, than others, but works just fine hand held, no problems.

It is more red than others. Everything else I have tried is more orange.

 

Maybe you mean 'they' when you say 'you'? In that case, then the reason is because 'they' don't want to reveal technical details about a filter to people,

it might help people duplicate the recipe, it destroys the mystery, and mystery sells.

Many filter companies don't show any graphs for their filters, which always annoys me, but people fall in love with the mystery.

 

I am not sure I understand your question about gluing the layers together. There is nothing wrong with gluing filter glass together, that is how combined transmission is made.

There are many filter stacks that produce special transmissions when stacked (and/or glued) that no single filter can produce on its own, unless some special dichroic filter were designed to so something similar,

and that is not always the best way to go either.

Gluing layers of filter glass together is perfectly normal. Calling that 'fused' seems to imply something that is melted together.

It isn't important.

 

Thank you for clarifying how filter stacks are fused together. I don't like gels. They cut a ton of light, which also cuts out detail. My orginal goal was to recreate the IRCHROME with budget filters and I did. Now I want to understand how it works. I can estimate the amount of transmitted light with the big blue filter stack. Using the data that the irchrome has a cutoff at 850nm, I can estimate the Transmittance curve.I just need to know how much blue light it blocks to IR light it blocks. Once I get that data, I'll be able to choose glass to buy in a cyan color. I already have the cokin 050 on the way. That should be a good test for testing.