Rainbow spectrum filter in Bliss (2021)

[Alissa Alexina]

Can anyone tell more details about the rainbow spectrum filter in Bliss (DP Markus Förderer)? Online articles mention a "custom light filter", but this is too vague of course. There is a BTS photo available, but I am not sure what is going on there, are they using some kind of prism as well? I think the effect is unique and beautiful - lnever overwhelming or cheesy like in commercially available filters - and wonder if it is possible to DIY something like this.

[Kyryll Sobolev]

i wonder if we can find more bts photos that would be clearer what is in front of the lens

looks like a glass or prism on a 114mm diopter attachment in front of the lens

Edited February 14, 2021 by Kyryll Sobolev

[Kyryll Sobolev]

from markus's website we can see what it looks like. no idea what that adhesive film is though

https://www.markusforderer.com/spectrum-filter

 

39aef2_8e7c31086a9d4e9daf5ce37a3c405217.webp

Edited February 14, 2021 by Kyryll Sobolev

[Phil Rhodes]

That's a diffraction grating of some kind. No idea where you'd get one that big or how you control the density.

P

[Alissa Alexina]

Thank you! So it is indeed a rectangular filter in the mattebox. I was wondering how they achieved the spectrum effect in various frame regions, without direct light sources - from the BTS it looks like they were strategically hitting the filter with a flashlight!

The diffraction grating film may be available somewhere like aliexpress... worth experimenting ?

[Phil Rhodes]

I'm not sure how exactly he has it mounted; it could be clamped onto the edge of the mattebox with a magic arm to catch a light that's coming in at some odd angle.

 

[Kyryll Sobolev]

yes i am sure there was endless experimenting with something like this from amazon

jeremy benning, DP for "the expanse", recently shared another funky filter that he thought of.
in his words, it is "a custom filter sandwich that incorporated green glitter floating in mineral oil and smeared with green-tinted Vaseline and lit with an LED light internally to create variable sparkles"

you can watch the effect here: https://www.facebook.com/watch/?v=1639128986296082 
(i think he only posted it to facebook)

[Alissa Alexina]

This is all very interesting!

By the way, looking through amazon options, I noticed different types of diffraction grating, such as linear, double axes, and spiral.

I have an idea that maybe double axis grating produces a star rays effect around light sources (like the Cokin Universe filter I have; I believe some version of it was used in "Love Witch"), and linear version can produce horizontal streaks like in Bliss?

[David Mullen ASC]

For the rainbow effect in "The Love Witch" for drug sequences, I used an old Cokin diffraction filter -- but it is more of a star filter, not a single line.

[Alissa Alexina]

Yes, this is exactly what I was referring to ? I was so impressed by this Love Witch scene that after reading the thread, rushed to ebay and was lucky to find a used Cokin diffractor. The filter looks like some kind of plastic with rainbow reflections, so it is probably based on the same principle. That is why I had an idea it may require a different kind of diffraction grating film - linear - to get just horizontal streaks.

Nets are a totally different thing (though just as interesting) - they do give a very subtle rainbow diffraction effect, but in the form of concentric circles around sunstar rays. Their main advantage over glass cross filters is that stars have much shorter rays, not so overwhelming.

[David Mullen ASC]

https://www.edmundoptics.com/p/12700-linesinch-6quot-x-12quot-sheets-2pack/11226?gclid=Cj0KCQiA1KiBBhCcARIsAPWqoSpHmc8SPnS-Ucgf04x6O__aFqkgxGrSGJZQhMfeQli1Uv6HG03dAhwaAotoEALw_wcB

I don't know if you can shoot through this stuff...

[Phil Rhodes]

13 minutes ago, David Mullen ASC said:

I don't know if you can shoot through this stuff...

I would expect it to turn the whole frame into a smeared spectral mess, splitting up the whole picture.

The shots Alissa cites look like glints reflecting in from outside the main picture area, almost like the effect you get when mounting a prism on the mattbox on a magic arm, or something like that. I wonder if that's how it was done.

P

[David Mullen ASC]

Or perhaps the diffraction sheets were cut into thin strips and placed across the frame selectively.  Or some sort of thin prism like you say.  Or perhaps some glass was at a 45 degree angle to the lens reflecting a diffraction sheet that then had a small light hitting part of it, so the camera only saw a reflection of that one area of the sheet?

[Alissa Alexina]

Thank you David! I was thinking of cutting the film into strips for selective placement on a clear filter, too. Although Markus Förderer"s filter is totally covered with holographic film, probably they were able to find something translucent enough.

Phil, no, we did not use a prism in the test shots. Somehow the Cokin diffractor multiplied the lightsaber light, though it was not supposed to ?

[Stuart Brereton]

23 hours ago, Phil Rhodes said:

I would expect it to turn the whole frame into a smeared spectral mess, splitting up the whole picture.

Yet the filter he's holding in the picture on his website appears to have diffracted light across the whole surface.

[Phil Rhodes]

6 minutes ago, Stuart Brereton said:

Yet the filter he's holding in the picture on his website appears to have diffracted light across the whole surface.

It seems I might be in a position to answer this definitively fairly soon; wait out!

[Stuart Brereton]

2 minutes ago, Phil Rhodes said:

It seems I might be in a position to answer this definitively fairly soon; wait out!

Good! The earliest Amazon can deliver a sheet of this is sometime in March ?

[David Mullen ASC]

I see online that there are also acrylic blocks with diffraction gratings in them so it seems that someone should be able to make a filter that way, besides the existing Cokin 8-point star one.

[Joshua Cadmium]

I have no idea if it's this exact filter, but the images do look a lot like the Rainbow filter from IB/E Optics: https://www.ibe-optics.com/en/products/cine/artistic-tools/organic/rainbow-10585 .

[Alissa Alexina]

Yes, the effect looks spot on! Their bespoke filters with rainbows, golden nets and dandelion seeds probably cost a fortune ? Some nice ideas to DIY.

[Satsuki Murashige]

24 minutes ago, Alissa Alexina said:

Yes, the effect looks spot on! Their bespoke filters with rainbows, golden nets and dandelion seeds probably cost a fortune ? Some nice ideas to DIY.

A lot of the fabrics that they are using in their filters can be purchased at fabric shops very cheaply. I recognize some of the mesh, tulles, and nets. You can just stretch them over an empty filter frame or the front/back of a lens without having to buy an expensive glass filter.

 

[Phil Rhodes]

19 minutes ago, Satsuki Murashige said:

A lot of the fabrics that they are using in their filters can be purchased at fabric shops very cheaply. I recognize some of the mesh, tulles, and nets. You can just stretch them over an empty filter frame or the front/back of a lens without having to buy an expensive glass filter.

 

Call it glassless optical path modification technology, claim it reduces unwanted reflections, and charge extra.

[Satsuki Murashige]

6 hours ago, Phil Rhodes said:

Call it glassless optical path modification technology, claim it reduces unwanted reflections, and charge extra.

Always, always charge extra...

[Joshua Cadmium]

8 hours ago, Alissa Alexina said:

Yes, the effect looks spot on! Their bespoke filters with rainbows, golden nets and dandelion seeds probably cost a fortune ? Some nice ideas to DIY.

I was thinking that the actual price, while high, wouldn't be that bad for high toleranced optical glass, but this filter would actually be $1,176 from Band Pro! That is pretty expensive for a filter. (And it's not just this filter - all of their filters are either $1,176 or $948: https://www.bandpro.com/brands.html/ib_e_optics .)

[Phil Rhodes]

Short answer: it's a special. The filters used for Bliss were specially built some time ago. Two exist, owned by Markus, and have not been used on anything else.

This is not the IB/E thing, but they look similar.