Old brass lenses - what was the original finish like?

[Jac@stafford.net]

I am not very much into old brass lenses, so over the many years when I saw one I bought it only if the glass was exceptionally clean, and the brass was fairly clean. As a result I have a couple beautiful looking brass lenses which perform adequately for portraits.

The other day someone said, "Too bad. It looks like they have been polished. A lens that old would have scratches." I was a bit shaken, but then I realized I have no idea what they might have looked like when new.

Finishes may have varied, but does anyone know how the higher end lenses were finished, what the brass looked like?

[ederphoto]

Most of the time just lacquered or finished in a semi-gloss black oil paint .Some were primed before being painted .Some were sanded and buffed after being painted and some not .Some of the most common brass lenses are Darlot and a huge number of Cooke lenses .There's just too many out there to list them here .I've seen brass Veritos and brass Pinkhams and most of the ones we see are painted black .The brass ones are the rarest .And this could go forever ...

[coisasdavida]

Banana extract was widely used to finish brass, it gives it a golden tone.

[E. von Hoegh]

I am not very much into old brass lenses, so over the many years when I saw one I bought it only if the glass was exceptionally clean, and the brass was fairly clean. As a result I have a couple beautiful looking brass lenses which perform adequately for portraits.

The other day someone said, "Too bad. It looks like they have been polished. A lens that old would have scratches." I was a bit shaken, but then I realized I have no idea what they might have looked like when new.

Finishes may have varied, but does anyone know how the higher end lenses were finished, what the brass looked like?

I have some rather old things, going back to the 1820s, which retain some (sometimes most) of their original finish, and I get comments like that from time to time. There's something that very few realise - it's possible to use something carefully and respectfully for a vey long time, that item will not retain all the original finish but it will look suspiciously clean to some not-very-careful people. Once upon a time, people knew what quality is - they bought something of high quality, and took care of it!

Assuming something old would have scratches is fallacious.

[IanG]

Vast majority were hot lacquered with a shellac varnish, it's a technique that's been used for many years. Pete Watkins has described how to do it in a thread on this forum, it was a technique he used at work in the 1900's.

Ian

[John Kasaian]

Vast majority were hot lacquered with a shellac varnish, it's a technique that's been used for many years. Pete Watkins has described how to do it in a thread on this forum, it was a technique he used at work in the 1900's.

Ian
Ahhhh! The good ol' 1900's! I knew them well:rolleyes:

[ederphoto]

Lol

[Steven Tribe]

Most lenses have suffered from non-separate storage when not in use - and when removed from the camera are in the danger zone when stored unprotected with other items.
As mentioned, heated barrels and dissolved shellac - plus secret additives - produced a fine and strong protection.

I have telescopes from the 1790's which have almost perfect original finishes - always stored in card cases with shagrin covers - unlike most lenses.

The metal finishing of the brass shows some variation in what the makers considered correct. I can clearly see microscopic "turning" marks under some lenses (market leaders!) with intact lacquer and a "mirror" brass surface was apparently not wanted.

How is this a D-I-Y thread?

[IanG]

How is this a D-I-Y thread?

It might be when we get Pete to describe what's in the shellac mix :D

We did discuss this subject when we met recently. I'm quite happy y7o experiment as I use shellac on a regular basis as I prefer to french polish rather than use modern aerosol lacqueurs on restorations.

The colour will depend on the type of shellac used, TTH seem to use a darker shellac than the blonde used on some other makes. I will start using it on brass vcamera fittings once I've mastered the technique.

Ian

[goamules]

I am not very much into old brass lenses, so over the many years when I saw one I bought it only if the glass was exceptionally clean, and the brass was fairly clean. As a result I have a couple beautiful looking brass lenses which perform adequately for portraits.

The other day someone said, "Too bad. It looks like they have been polished. A lens that old would have scratches." I was a bit shaken, but then I realized I have no idea what they might have looked like when new.

Finishes may have varied, but does anyone know how the higher end lenses were finished, what the brass looked like?

Like said above, it all depends on how it was treated. I've got a couple of 1860s lenses whose original varnish looks almost new. Your friend doesn't know antique lenses. The varnish protects the brass from scratches, but you'll sometimes see some where the waterhouse slot is. You will see them with splotches from oxidation getting under the varnish, or varnish flaking. Some makers, like voigtlander, had very thin varnish, which can be wiped off over the years from mounting and dismounting the lens from the camera.

[Pete Watkins]

I can only talk about what we used to do in the early 1960's (God I'm bloody old!!!). The brass to be laquered (not varnished, varnish was for wood) was either polished or grained. It was then washed in what at the time was leaded petrol, we didn't have access to unleaded so it wasn't a choice, just availability. The brass was allowed to dry then heated up and laquered while it was hot. If it was too hot the laquer boiled on the brass and you had to start all over again. The laquers were all shellac based and bought from a shop named Gedges in the Clerkenwell area of London. Different shades were available. If you want to make some up this works:-
You need
1/2 oz of Annatto
1/2 oz of Saffron
2 oz of Tumeric
6 ozs of Seed Lac / Shellac in coarse powder form
2 pints of methalated spirits
(all the measures are U.K. Imperial, the U.S. pint is slightly different and no I can't convert this stuff to metric)

Mix the first three ingredients in the alcohol and leave for several days shaking it daily.
Strain this into a bottle containing the shellac and shake it up until the shellac is dissolved

Extra colouring can be obtained with the addition of more Saffron, Gamboge, Dragons Blood (???) or Aniline

I think that the brass lenses that were finished in black (TT&H, Ross and others) were sprayed with a laquer type paint. This would obviously save money as hot laquering was done by hand and was labour intensive. The black paint/laquer appears to be fairly thick and I've never seen one with brush marks so I'm assuming that they were sprayed but if you know better please join in.
Hope this helps,
Pete.

[IanG]

Turns out shellac based Brass lacquer is available off the shelf from Horology suppliers, essential the same as French polish either clear or with colouring. The magic ingredients of the past such as Dragons blood are just colouring agents. The modern technique is to apply cold then heat with an air-gun, the old technique was to apply to pre heated parts. A variable would be the strength of the alcohol, I make up my own French polish and prefer to use close to 100% in my French polish but that needs a licence to buy it, however the local home brew shop sells a small distillation kit :D

Got distracted Pete you hadn't posted when I stared writing. It's the colouring thats important, the Tumeric etc but I think modern dyes can be used now which weren't available a few years ago.

Ian

[IanG]

The black lacquers would have been brushing enamels like they use(d) in the motor trade they go on quite thick but tend to dry thinner and not show brush marks.

Ian