View Full Version : Blacken Petzval Inside

14-Feb-2017, 12:37
I have a ~6 in. Derogy Petzval from the 1850s I'd like to add to the stuff I've piled on my dining room table for "spring cleaning." (When you start buying something new because you can't find something you already have, it's a clear sign you have too much stuff.) Anyway, some clown that owned this before decided to give it a good cleaning and polishing--outside and inside! The shiny brass on the inside makes this thing a flare puppy. SO, to make the future owner happier with it than I was, I want to re-black the surface. I think back in the 1850s they used lamp black? I'm all out and didn't find any at the hardware store. What should I use to paint the inside of this lens to make it more user friendly?

Kent in SD

14-Feb-2017, 12:54
Kent, your concern has been our collective concern for a very long time. Several opinions will emerge Real Soon Now.

My favorite for a surface not subject to weather is thin black flocking paper. My second is a Testor flat black, but it is so less effective than black flocking paper I won't go on.

Good luck, Sir!

14-Feb-2017, 12:57
The easy way would be to use India ink... Commonly used in lenses, traditional, reversible, thin, won't clog threads, etc...

Steve K

14-Feb-2017, 14:08
flocking paper. they make a self-adhesive version.

Eric Woodbury
14-Feb-2017, 16:26
I agree, flocking paper is very good because of its micro surface texture. It's not always practical, however. Years ago I tested a bunch of black spray paints; anything I could find in the local hardware stores. It is amazing how black has so much variability. More than a stop, almost two. I measured orthogonal to the surface (straight-on) and at low angles. Best I found at the time was Krylon's UFB, Ultra Flat Black.

14-Feb-2017, 16:43
I think flocking (velvet) wasn't used until around the time Karl Struss started making his lenses which would be a lot later than the Petzval. Black self adhesive flocking paper works real nice though. I also put it on the back of lensboards to reduce inside-the-camera light reflections. http://www.scopestuff.com/ss_flok.htm is what was recommended to me from someone here.

Mark Sawyer
14-Feb-2017, 18:58
If you go the flocking paper route, get the stuff amateur astronomers use to line their telescope tubes. Ultra-black, self-adhesive, and fairly inexpensive.

Peter De Smidt
14-Feb-2017, 20:09

14-Feb-2017, 20:12
Lamp black is the smoke from a coal oil lamp and is easily done , provided you can separate the tube from the lens. Just hole the tube over the wick and rotate a bit at a time and you will get the hang of it. If you want to redo it in more smoothly after you get it, just wipe off the first try layer. If you don't like the whole thing just wipe it off. If you turn and move the tube and get a just covering layer it does not flake off. It works great.

Jeff T
14-Feb-2017, 21:28
Rustoleum high heat paint in black.

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14-Feb-2017, 22:00
Hmm. It's a small lens, maybe 2 in. diameter and 3.5 in. long. I could try the smoke thing. Would kerosene work? Don't think I have the old fashioned coal oil available.

Kent in SD

14-Feb-2017, 23:19
This (https://www.birchwoodcasey.com/Refinishing/Metal-Finishing/Brass-Black-Touch-Up.aspx) would probably work


Steven Tribe
15-Feb-2017, 01:19
This is almost a complete repeat of an earlier thread with some familar names!


Chemical blackening with copper dissolved in nitric acid is the old production method. As the solution has to "burned off", re- lacquering of the outside brass is necessary. Lamp blackening is hardly a permanent solution!

15-Feb-2017, 09:20
Yes kerosene is appropriate and it lasts if you don't touch it. Which you don't.