burnt embers

I am hoping that my some questions I have regarding the performance of my new-to-me Zero Image 2000 pinhole camera can be answered by some of you readers. These pictures were shot on Worldwide Pinhole Day a few days ago in full sun. There are a few issues that I would like some control over, most to do with flare. I don’t mind a bit of flare, but the circular flare on most of these pictures (see the gallery below) is often a bit much, especially the brighter spot in the middle of the circle.

Thus my first question regards the circular flare which has a radial line extending from the center, pointing almost exactly at the sun. This flare occurs in nearly every shot whether or not the camera is in sun or bright light. I am wondering if it is a result of the camera construction. Does it originate from reflections in the shaft of the pinhole itself, or is it reflecting from the shiny brass pinhole fixture either on the outside of the camera, or the inside? If so, would I blacken these surrounds to control it, and would a felt pen do the trick?

EDIT: My Zero 2000 is “1st edition”. I have found detailed photos of the “2nd edition” of this same camera (here) and those photos clearly show that the brass surround on the inside and outside is blackened (“enameled” they claim in the text), and the brass foil with the pinhole through it is also blackened on the inside (this image) but not the outside (this photo). So, I think this is a safe place to start in order to control the circular flare. I will use a felt pen on the inside of the foil as I don’t think the ink will constrict the pinhole. And I will apply some kind of black paint to the machined brass. While I am at it I will paint the other brass fittings that extend into this part of the camera to eliminate reflections from them.

Shutter open, shiny brass surround of pinhole.

The second issue is the occasional horizontal strips of beaded light. Is this because light is getting under the “shutter” and reflecting into the pinhole even when it is closed? The wood of the shutter has pronounced grain and the finish is glossy so it might be the source.

Interior showing pinhole assembly. Source of reflections?

The third issue is a slightly sticky shutter which means it is not always fully opened, or at least not immediately leaving an unexposed or underexposed bar on the right side of the image. If the slightly loose cover is causing the beaded flare, then I would like to tighten it. But if I tighten it, opening it fully will be more difficult. Has anyone modified these in some way – such as a thin layer of felt on the underside. If some kind of fabric was used, does it create dust that gets on or in the pinhole? Is there a material that would prevent this problem, or that would minimise friction so that it can just be tightened?

Shutter when closed showing gap beneath it in area of pinhole. Source of beaded flare?

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Zero Image 2000 pinhole camera, Fuji Neopan Acros 100, commercial processing and scan