Konica Hexanon 40/1.8 weird color

[NikonD]

Just got this lens and I've expected it to be all black... am I missing something?
to ge honest I like it

[kypfer]

Mine is all black.
I've seen that dark purple sheen ... it comes from a "Sharpie" pen ... it'll probably wear off quickly enough or wipe off immediately with a drop of alcohol.

[kiddo]

I would call it baked formula, heating the outside black metal parts I side the oven would turn from black to the reddish color from that picture

[NikonD]

[NikonD]

here it's compared to other konicas from my collection... the color is exactly the same as I see it with my eyes

[kiddo]

[RokkorDoctor]

The (black) dyes used in anodising were usually a closely guarded proprietary formulation (not sure if they still are these days, and not sure about other colours).

Poorer quality black dyes were liable to get a reddish or blueish sheen over time; I e.g. have some older Minolta early ROKKOR lenses do the same on me, the later ROKKOR lenses are always fine (post - Leitz/Leica collaboration funny enough, may or may not be a coincidence. E.g. from memory I read somewhere that Leica also shared their black chromium finish procedure with Minolta).

Yours looks extreme though; may well have been someone touching it up with a sharpie.

[NikonD]

[kiddo]

It's baked purposely by some other owner or factory itself (special edition lol) - you guys try it with any cheap lantern,same result

[alex_d]

if those parts are aluminium(probably) then it's (something) about anodisation.
it's not strange to have a bit different color sometimes, even by accident.

the fact that 40/1.8 came from a different factory than other konica lenses (according to wide-accepted knowledge) could also be an answer.

I think i have seen a bit mis-colored example (or i even have it somethere), however much less then from your picture.

[caspert79]

I’m pretty sure this is a DIY modification.

[stevemark]

[caspert79]

[NikonD]

got some time with the lens today... I think it's seen the sun a bit too much... it looks like the sun bleached the color
there a bit of black on the back side of the lens... when it's mounted on a camera it's under the lens... I guess where the sun don't shine... Could have been a display lens?

[BrianSVP]

No one "did it." It's simply faded anodizing dye. Can be caused by a bad batch or using the lens in an alkaline environment or sitting in strong sunlight for an extended period, which is probably what happened here. Pretty common occurrence, actually. Manufacturers used black dyes with different undertones in different models/batches, so, for example, I have a Konica AR 50mm f/1.4 that has similarly faded but looks bluish rather than bronze.

Considering the back half of the front barrel isn't faded, it was probably left with the focus at infinity for a very long time, which protected that portion while the rest of the lens was exposed to whatever caused the fading. The aperture ring and name ring on this model are plastic, which is why they remain unfaded.

[BrianSVP]

The black chrome was only ever used on the camera bodies, not on the lenses themselves, which by the time the black nickel chrome was introduced were all anodized aluminum.

[kiddo]

if it would of be left unused on the sun, would have the aperture ring same redish color instead black;probably when they baked it , they left the two rings inside , that´s the reason same ring would have two color
honestly, i cannot believe lenses would turn that color by the heat/light of the sun, to bake anodized aluminum for changing color, it needs plenty of heat
there might be the option that some bad quality batch came out like that to the manufacturer , and somebody thought about putting it together (maybe some award for employee)

[stevemark]

[visualopsins]

https://youtu.be/lFqABKH2taE

[Doc Sharptail]

I've got a few cheap aluminum rifle scope bases that are plum purple like that- directly from he factory in China.
The finish seems to adhere just as well as the black on the Weaver scope bases...

-D.S.

[stevemark]

[visualopsins]

Plum Brown Barrel Finish
https://duckduckgo.com/?t=ffab&q=Plum+Brown+Barrel+Finish&atb=v411-4__&iax=images&ia=images

[kiddo]

Few years ago I've seen a guy baking some black anodized flashlights, same color result and changing , depending on the temperature and time exposed
https://www.reddit.com/r/flashlight/comments/ccsgdu
https://www.reddit.com/r/flashlight/comments/ccsgdu/before_and_after_heat_treated_s2/
I can believe sun light heat can change colors in many items , but regarding anodized aluminum it requires lot of heat as far as I've read
https://budgetlightforum.com/t/fw3a-mod-thread-post-yours/56663/9

[BrianSVP]

The dyes used to anodize aluminum are not substantially different from the ones used to dye clothing. The freshly anodized surface is porous and absorbs the dye, and then the pores are sealed either through heating (boiling/steaming), which closes the pores, or with a nickel acetate or similar sealant. While chemical sealants provide some degree of protection to the color, even they don't block 100% of the UV in sunlight, which will bleach out the color in exactly the same manner it does your bedroom curtains.

Color loss can also be caused by alkaline environments, which gradually break down the oxide anodized layer, allowing the pores to reopen and the colored dye to physically wear away. This is essentially a slo-mo version of the lye dip typically used to strip an existing anodized layer prior to re-finishing.

These Konica 40mm lenses contain a substantial amount of plastic, not just the aperture and name rings, but also portions of the helical. In order to bake it and not melt them, you'd have to strip it down to individual components, and bake them individually, in which case, you wouldn't see the two-tone fading as you do on the front barrel.

You're barking up the wrong tree here. Occam's razor says it's almost certainly the simpler solution - environmental factors caused this fading, either UV/sun light (more likely) or exposure to alkalinity (less likely, since there isn't evidence of other corrosion).

[BrianSVP]

Here's a pic of the Konica AR 50mm f/1.4 I mentioned upthread.

Most people don't realize that all black dyes have a base color undertone. You might have noticed this if you ever have accidentally gotten chlorine bleach on a black garment, leaving bleach spots that aren't gray or white, but some other color. In the case of the 40mm, the undertone of the black anodizing is bronze, which is revealed as the black fades. In the 50mm f/1.4 below, the base color is blue.

This isn't as extreme example as the 40mm at the top of this thread, but if you compare the front barrel and the focus ring, which is where the fading has primarily occurred, you will notice that it is fading to a base tint of blue, while the lower barrel portion remains nice and black.

These are probably the two most common undertone colors used in black anodizing dyes (bronze for a warmer black, blue for a cooler one), so it's no surprise that either would show up on faded lens barrels. Konica obviously has employed both in different lens models.