Antique Plate Camera Mild Refurbishment

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As some may already be aware, I recently bought an old 19th century tailboard plate camera from Asha. In the sale thread, I mentioned that I plan to use it, and that means that it needs to be checked over and any issues addressed. As expected, given that it is already a working camera, the issues I found are minor and straightforward to take care of. In this thread, I'll describe what I found, and what I did, as well as add comments about the camera as I find things out.

The first thing I looked at was the tripod mounting. The thread for this was neither 1/4" or 3/8". I measured the diameter of the bolt that came with the camera, and got a smidge under 7.8mm, which is very close to 5/16", and a thread pitch gauge told me that the pitch was 18 tpi (threads per inch). A check online for some Whitworth thread specs confirmed that it was 5/16 BSW, so a die and some taps were duly ordered.

When they arrived, I made a new screw that would fit into a Manfrotto 410PL quick release plate. Here's the new screw, surrounded by the two modern screws that came with the plate, and the bolt that came with the camera...

Marion Tripod Screw 01.jpg

It's made from hexagonal profile brass bar, mostly on a lathe.

Fits the plate nicely...

Marion Tripod Screw 02.jpg

I milled a little slot in it so that I can tighten it up with the screwdriver on my Swiss army knife...

Marion Tripod Screw 03.jpg

It all seems to tighten up nicely and sits well on the tripod.

That gave me a chance to focus on distant objects through the window and get a handle on the focal length of the lens and see what the apertures are in reality.

The focal length looks to be 8", or 203.2mm if you don't speak groats and cubits. The diameters of the openings in the aperture wheel were then measured. Here's the list of diameters with the engraved numbers on the wheel...

11 - 14
16 - 10.1
22 - 6.6
32 - 4.8
44 - 3.56

When the areas are calculated and compared to each other, the stops aren't quite double/half, but are pretty close. From the '11', the ratios of the subsequent areas are 1.9x, 2.3x, 1.9x and 1.8x. What's more relevant is the calculation of focal length divided by diameter to get the actual f-numbers...

11 - 15
16 - 20
22 - 31
32 - 42
44 - 57

In practical terms, the real f-stops in modern-speak are: 16, 22, 32, 45, 64. So, to set an f-stop, I just go up one from the number on the aperture wheel. In spite of being f/16 at max aperture, the image on the ground glass was surprisingly bright - easy enough to focus in a darkened room looking outside, with no dark cloth.

More to come...
 
What a brilliant start to what is clearly going to be an excellent thread!:)

The calculations concerning the apertures is very interesting especially now being aware that the "true" max aperture is F/16 as opposed to F/11 marked on the aperture wheel of the lens.

Your skills at metal work are brilliant and of course mean that you can now attach the camera directly to the tripod QR plate without need for the adapter tha I included in the sale.

P.S
Thank you for stating both milimeters and inches as although as a young man I understood both quite clearly, 15 years of living on the continent has seen me become somewhat "rusty" with groats and cubits!:LOL:
 
The odd thing with the apertures is that I haven't found a historical scale that matches. Some more searching to be done. I mostly do metric, but I'm fairly dimensionally ambidextrous. On with the next bit...

In the shot above, with the plate fitted to the camera, there is a channel in the wood, to the right. Here's a better view...
Marion Latch 01.jpg

In this shot, the channel is in the base of the camera, the metal bit is passing over the bottom edge of the folded-up tailboard, and the third bit of wood, with the semi-circular cut-out (nearest the viewer) is the panel that swings in and out depending on whether the camera is open or closed. Given that there are two holes at one end, there is clearly something missing.

Here's another view, more from the side...

Marion Latch 02.jpg

When the camera is open, the hinged panel moves out and the tailboard drops down. When viewed from underneath, the adjacent edges of these meet up like this...

Marion Latch 03.jpg

The stabilising panel is nearest the viewer, and we're looking at a sliding bolt that's on the underside of the tailboard. The bolt is slid in about half-way in this shot. This locks the two panels together to improve rigidity, which means the tailboard stays in position and doesn't flap about in the breeze.
 
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Returning to the channel in the base of the camera, now with the tailboard open, we see...

Marion Latch 04.jpg

...that the channel extends into the adjacent edge of the tailboard, obviously clearance for whatever was originally there.

After a bit of thought, I made a thing from brass...

Marion Latch 05.jpg

It's basically a little leaf spring which acts as a latch to hold the stabilising panel in place when the camera is closed. There's a small rectangle of brass soldered onto the underside which catches on the hook shape of the bit of brass on the panel...

Marion Latch 06.jpg

I had to use new screw positions because one of the original holes still had a bit of screw in it about half way down. No way that was coming out easily.

At the moment, it doesn't quite click when the stabilising panel is brought up to the back of the camera - I can close it, but need to give the end of the catch a little press to get it to engage. I'll fettle the edge a little when I next take it off. I may also apply some patina to darken it.

Disengaging is fine - just get a fingernail into the semi-circular cut-out and ease it up.
 
When you initially mentioned the missing "catch" upon receiving the camera, I had difficulty in picturing exactly where the location was of the original piece.

Now, following your superb explanations, it is perfectly clear.(y)

As it was with quite a heavy heart that I sold the Marion, it is quite heart warming to see the work that you have already done towards returning her to good use.
Without a doubt the camera has gone to someone with dedication and passion! :ty:
 
Far be it from me to nit pick but galv. posi-drive screws?

Good job all the same :)
 
Far be it from me to nit pick but galv. posi-drive screws?

From a practical point of view it's irrelevant but yes now that it's been mentioned perhaps brass screws would be more apt.
 
It always had my name on it, Asha. :)

The screws aren't galv, but have some sort of shiny plating. I did consider brass, but I didn't have anything nearly small enough. The wood there is 3/8" thick (~9.4mm), and the screws are 8.5mm long. Also, brass can be pretty fragile when the screws are this small, and the threads in a traditional style of screw don't have much bite. These are a more modern thread that cuts into the fibres better and results in a stronger grip. Given that the catch will impart a pull force on the nearest screw at least, I think these are the better choice in terms of strength. I did consider ordering some tiny brass screws, but decided not to in the end, partly due to wanting to get on, and because they were only 1/4" long, so would have marginal grip.

While messing about with the camera on the tripod, generally looking in the back while shining a torch on the bellows to check for holes, I found a light leak at the lens board, at the top left in this shot...

Marion Lens Board 01.jpg

A shot with the camera flash switched on made things clearer...

Marion Lens Board 02.jpg

Looks like a crack. Sure enough, it continues through to the front...

Marion Lens Board 03.jpg

At a distance, this isn't really noticed. If anything, it could be taken for a dark line in the wood grain. Also, due to the width of the crack compared to the thickness of the board (about 1mm and 5mm), it's the sort of thing that would be quite elusive - you'd need pretty directional lighting coming from the right direction to see anything in the image. That said, once it's known about, it has to be fixed.
 
it has to be fixed.

and I know a "MrFixit"! :LOL:

I'm presuming that you can simply fill the crack?

Ensuring it's light tight is going to obviously dictate what product you use so what do you have in mind?
 
With the lens board off, the reason for the crack started to become apparent...

Marion Lens Board 04.jpg

In the three positions where the flange retaining screws are (10 o'clock, 2 o'clock and 6 o'clock), there are three light patches a little further out. They are spots of some sort of filler that has been put into holes in the panel. This suggests that the lens flange isn't the original - the lens has been changed and the original holes filled.

Sure enough, a close look at the front confirmed this...

Marion Lens Board 05.jpg

There is a clear witness mark in the finish, showing the extent of the original flange.

This somewhat scuppers my theory that G Knight of Southsea bought the camera in from Marion & Co, fitted one of their OEM lenses and sold it. There's no telling when the lens was changed, or whether G Knight ever saw the camera. All we know is that the two items were put together at some point.

Anyway, a repair was in order, so the flange came off. At this point, I took the opportunity to do a little test. I had been wondering about the finish on the outside of the camera, and whether it might be shellac. With the flange off, I had an area that would be hidden to experiment on. For those that aren't aware, shellac dissolves in alcohol (the hard, brittle stuff is dissolved in alcohol to enable painting it on). A did a bit of rubbing with a cotton bud dipped in bio-ethanol, and managed to remove some of the finish...

Marion Lens Board 10.jpg

The dull bit near the edge is where it came off and left deposits on the cotton bud (I cleaned it first, and then used a fresh bud to see if more came off, which was the case). Handy to know if I want to refinish any parts (I might do so on the bits of the base around the tripod socket).
 
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So considering other wood varnishes, was shellac one of the better and most often used products on cameras ( and possibly furniture) of this era?
 
The first thing to do was get the old filler out of the area to be repaired...

Marion Lens Board 06.jpg

The result of much careful poking with a tiny jeweler's screwdriver and a scalpel used backwards (using the back of the blade to draw bits of material out). If there was ever any doubt about the second set of holes...

Marion Lens Board 07.jpg

It's hard to say what caused the crack, but I suspect the addition of the new hole nearer the edge.

Once the filler was out, I checked to see if there was any movement in the crack to see if there was a possibility of just running glue in and clamping things together. There was no movement (I guess this happened a long time ago and the wood has settled into this position), so the answer was to fill it.

I did this with some home-brew filler consisting of fine ebony dust and Titebond Original wood glue...

Marion Lens Board 08.jpg

The stick in the background is about 10mm wide, which gives an idea of the scale.

There was no special reason for using this - I don't have any wood filler, but I do have ebony dust and glue, so this was easy to make up.
 
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This somewhat scuppers my theory that G Knight of Southsea bought the camera in from Marion & Co, fitted one of their OEM lenses and sold it. There's no telling when the lens was changed, or whether G Knight ever saw the camera. All we know is that the two items were put together at some point.

The plot thickens :thinking:……….
 
Here it is with the ebony & glue filler applied...

Marion Lens Board 09.jpg

After this had gone off for a bit, I was able to cut the bulk away with a scalpel. I then left it to set before sanding it smoother...

Marion Lens Board 11.jpg

An eyeball at it against a bright light indicates no leakage.

With that done, a bit of paint...

Marion Lens Board 12.jpg

Looks glossy because it's still wet. I like this Rust-oleum paint. It's proper, pongy old-school paint that needs to be left to cure for 24 hours at least. My initial tests with the matt black indicated that it's pretty durable as well. We'll see how this bears out with the lens board, since it has a sliding motion against the front of the camera.
 
What a great thread this is going to be,so interesting.

Fabulous work and I cannot wait to see the final results.(y)
 
So considering other wood varnishes, was shellac one of the better and most often used products on cameras ( and possibly furniture) of this era?
Shellac is the stuff that gave us the word 'lacquer'. It's secreted by lac beetles onto certain species of tree in Asia. The stuff gets scraped off and filtered to leave a hard, brittle substance like resin. It can be treated in various ways to make it lighter in colour (it's naturally amber), and to remove wax constituents (desirable for some types of finish, like sanding sealer - subsequent coats of paint have better adhesion). It's also the basis for French polishing - the wood is lacquered with shellac, and then buffed with fancy waxes to bring up the gloss.

It's lovely stuff - one of my favourite finishes, although my use of it is very utilitarian. It's extremely fast drying - touch dry in a few minutes, and well on the way to being cured in an hour or so. Being a lacquer, it doesn't build up in layers - there's no adhesion between applications like you get with paint or modern varnishes. What happens is the alcohol in the fresh application dissolves the surface of the previous one, with the result that the new shellac mingles with the previous shellac. As you build it up, you get an ever-thicker single, amorphous layer of shellac.

Yes, shellac would have been the main type of varnish used in the 19th century. Apparently, it continued in use until about the 1920s, when nitrocellulose lacquer was developed. It's possible that some finishes might have been based on drying oils like linseed, but they need a lot of applications to get a glossy finish, and a lot of time for them to fully cure.
 
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Thank you for the explanation ...very interesting!

the alcohol in the fresh application dissolves the surface of the previous one, with the result that the new shellac mingles with the previous shellac

Simplicity in itself when adding the additional coats .....Just brilliant.
 
The plot thickens :thinking:……….
About the only other thought I've had regarding the history has been the serial number of the lens - 9793. I used Google Streetview to see if I could find the former premises of G Knight of Southsea, and I did. It's now a hipster cafe that has a vinyl records thing going on...

G Kinight Former Premises.jpg

It's a pokey wee place, and doesn't look like they were the sort of outfit that would be flogging lenses in the thousands. They were more of a semi-provincial photographic and optics seller. (They also occupied only one of the two shop fronts for a while.)

I'm wondering if their serial numbering scheme was maybe year and unit number within that year, which would suggest it was the 93rd lens sold in 1897, or maybe the 97th lens of 1893, or perhaps the 793rd of the 1890s. Something around 100-200 or so a year, maybe? That seems to me to be more believable for the apparent size of the business, and given that it would probably have been fairly high end kit at the time - I can't imagine there were enough well-heeled photographers in the Portsmouth area around then to sustain thousands of lens sales. Mass market- and mass interest - didn't really happen until the Box Brownie came out in 1900, and they were far cheaper than this would have been.
 
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My favourite thread for ages, brilliant. (y)
 
A bit of a fast-forward, here, but I'll summarise...

A bit more painting on the lens board had that sorted - nice and matt all over. The next thing to address was the septum in the plate holder. This was looking a bit grotty, as can be seen here...

Marion Septum 01.jpg

Marion Septum 02.jpg

It looks like some sort of light corrosion. At first, I thought it might have been staining from using the camera with wet plates, but there's no sign of it elsewhere in the plate holder - the wooden bits are all nice and clean. On the other hand, there are one or two other matt black areas of the camera that have similar whitish deposits, so I'm thinking it may be something in the black paint. I was considering using paint stripper to take this off, but decided to try sanding first. I wanted to check whether it was corrosion of the underlying metal (from the way it flexes, I reckon it's steel rather than brass). It turned out that the areas that felt rough (what I thought was galvanic corrosion under the paint) came up smooth with some gentle sanding. It seems that the original paint was quite soft (maybe like that chalk paint that some woodworkers use for making a distressed finish). I got the worst of it off and sprayed it light grey primer (acrylic) before applying some Rust-oleum black paint. I tried satin on one side, but wasn't happy - too much gloss. On the other, I used the matt black, but it was patchy. So I need to key the satin side and do a coat of matt on that, and apply a second coat to the patchy matt side.

At this point, impatience got the better of me and I turned my attention to a couple of 3D printed things I made - a lens cap and a filter holder. These were tidied up on a lathe to get the sizes a bit better, and some thin cloth tape was applied to the filter holder to ensure there was some benign friction to both keep it on the lens and keep the filter in place. I also cut a couple of spacers from thin MDF (photo clip frame backing), gave them a coat of shellac to seal them, and then cut a couple of bits of Multigrade IV to whole plate size. Loaded that lot into the pate holder and headed out to take a couple of photos.
 
First shot is Linlithgow Palace, 2 seconds at f/16, yellow filter...

Marion 001 - Lithgy Palace.jpg

Scanned at 600dpi and downsized. Some levels adjustment, but no sharpening or anything else. The main thing to note is the light leak at the right hand side.

Second shot was Blackness castle, 16 seconds at f/64, yellow filter...

Marion 002 - Blackness Castle.jpg

Same basic processing, no sharpening. Light leaks again, but in different positions.

I've just been looking at the interface of the plate holder with the ground glass fame, and it looks like there is some slack between the two. Basically, the tongue parts on the holder are narrower than the grooves they slide into. I'll do some thinking about how to remedy this, but the short term solution is probably to push the holder against the back of the camera when opening the dark slide, and to then drape the dark cloth over things to ensure there is minimal chance of leaks.

The top and bottom parts of the ground glass frame have screws going through from the frame into the top and bottom retainer strips, so one option is to remake these with the grooves a bit narrower. This is assuming they aren't glued as well - to be checked. Another approach is to cut some thin strips of wood and glue them to the grooves to make them narrower that way. At the moment, I don't think there's much scope for making the tongues on the plate holder wider. Either way, I found that pressing the plate holder against the frame didn't quite get rid of all of the light leakage - the corner at top-right when viewed from behind the camera still had a bit coming through (dark room, torch shining directly in), so I think the velvet strips that act as light traps will need to be replaced as well.

When I get around to addressing this, I'll take the time to do the rest of the painting on the septum. Although impatience was what sent me out to take a couple of photos, it turned out that doing so was useful in terms of bringing the camera up to snuff - definitely better to have discovered the light leaks now on a couple of bits of darkroom paper than later on with the much more laborious hand-coated glass plates with their attendant very long exposure and processing times.

All part of the fun.

Actually using the camera was a breeze - not much different from using a more modern large format camera. No preview lever on the lens, and no shutter, but the exposure times are long enough to be able to use the cap. The only mistake I made was on the first photo, when I made the 2sec exposure and then realised I hadn't opened the dark slide - just refit the cap to the filter, open the slide and do it again.
 
I did the two photos at the extreme ends of the aperture range available to see what difference there might be. Sure enough, there is a big difference in sharpness at the edges. The following two photos are from the right-hand side of each of the full size ones.

Linlithgow Palace - look above for the clock tower at the right, and the swans on the loch...Marion 001 - Lithgy Palace - side crop.jpg

And the Blackness Castle shot, showing the gate and lamp post...

Marion 002 - Blackness Castle - side crop.jpg

Quite a big difference, especially when you consider that the lens already has a permanent stop that the wheel stop rotates within - if the wheel was taken out it would still be about f/16. If the permanent part was taken out to make the lens wide open, it would be closer to about f/5.6 (about 8" divided by about 1.5"). In other words, even when stopped down 3 stops from what would be truly wide open, there is quite a big loss of sharpness at the edges. Certainly a huge improvement at f/64, and it looks to really live up to its rectilinear moniker - that's incredibly free of barrel and pincushion distortion for something that was designed the 1860s. As I do a few more shots, it'll be interesting to see how the sharpness improves as the apertures get smaller.

Having said that, the loss of sharpness at the wide aperture definitely has an appeal - I'm not especially aiming to make modern-looking images with this, so being soft at the edges is a plus. (The idea is to know how soft, and be able to choose the softness when desired.)
 
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A word about metering and exposure...

I metered at 3asa and doubled the given exposure times. That was based on a starting point for paper of 6asa, plus one stop for the yellow filter, and then an arbitrary additional stop for the paper being quite old (probably a good 10 years or more). Lighting was slightly-diffuse sunny with wispy cloud, and the sun was behind me for both shots. The density in the negs is pretty good, although I'd say that the contrast could be a bit better. The light leaks are very dark grey rather than black, and the shadow areas are noticeably light grey compared to the unexposed white border areas. I might try a different filter next time.
 
A selective crop for artistic purposes...

Marion 002 - Blackness Castle - pictorial crop.jpg

A tiny rotation to get things horizontal and vertical, another tweak on the levels, and 50% unsharp mask in Photoshop. (Pardon the dust - I'm lazy.)

Nice tones in the foreshore, and I like the way the land in the background is paler and lower contrast due to the lack of red sensitivity in the paper (the ortho balance is a key thing that distinguishes old photos).
 
By far and away my favourite current thread, it’s wonderful to see the camera in use and your running commentary is excellent. Brilliant!
 
Shellac is the stuff that gave us the word 'lacquer'. It's secreted by lac beetles onto certain species of tree in Asia. The stuff gets scraped off and filtered to leave a hard, brittle substance like resin. It can be treated in various ways to make it lighter in colour (it's naturally amber), and to remove wax constituents (desirable for some types of finish, like sanding sealer - subsequent coats of paint have better adhesion). It's also the basis for French polishing - the wood is lacquered with shellac, and then buffed with fancy waxes to bring up the gloss.

It's lovely stuff - one of my favourite finishes, although my use of it is very utilitarian. It's extremely fast drying - touch dry in a few minutes, and well on the way to being cured in an hour or so. Being a lacquer, it doesn't build up in layers - there's no adhesion between applications like you get with paint or modern varnishes. What happens is the alcohol in the fresh application dissolves the surface of the previous one, with the result that the new shellac mingles with the previous shellac. As you build it up, you get an ever-thicker single, amorphous layer of shellac.

Yes, shellac would have been the main type of varnish used in the 19th century. Apparently, it continued in use until about the 1920s, when nitrocellulose lacquer was developed. It's possible that some finishes might have been based on drying oils like linseed, but they need a lot of applications to get a glossy finish, and a lot of time for them to fully cure.

It is the basis of french polish and is of course still used by furniture restorers. I use it quite regularly. it is ideal for repairs as it is so easily reversible.
But it is not a tough finish and like the original is easily damaged. If you want a black version simply dissolve old 78 records in meth. or better still pure ethyl or Methyl alcohol with out the additives.
My favourite finish for new work is danish oil. as it is to a large extent water resistant and can produce a lovely natural luster finish. But modern finishes do not take on old shellac surfaces, they need to be totally removed. However new shellac takes on old very well indeed to freshen them up. If they end up too shiny buff them down with grade 0000 wire wool and bees wax... good to do any way.
 
Thanks all - I'm glad this is of interest.

Terry, I find bio-ethanol (£6 for 2L from B&Q) works well with shellac. It's labeled as minimum 95% ethanol, and I assume it's produced from plant sources. It's water clear, doesn't stink like meths, and dissolves Liberon shellac flakes no problem. I've not used danish oil, mainly because it doesn't seem to be a defined formula but a blend of oils (linseed and tung?), maybe with some solvent. For my workshop benches and some tools/tool handles, I use boiled linseed. They all end up fairly matt because I only ever put a little on (not enough to build up a varnish-like layer).

Anyway, I've been thinking about the slackness in the plate holder that's causing the light leaks. Earlier, I said that I reckoned I could either make new top and bottom plates for the ground glass frame, such that the resulting grooves for the plate holder were narrower, or possibly shim them with some thin strips of veneer. It turns out that this isn't feasible, at least for the top groove that the GG frame mates with when the GG is in place for focusing. The tongue part of this is already a good fit, which would mean having to make the tongue thinner to fit into a groove that's been made narrower for the plate holder. I'd rather not go that far in terms of modifying the camera, so the solution will be to modify the plate holder after all.

I then wondered how critical it is to get the plate holder snug against the back of the camera - getting rid of the light leaks is a combination of reducing the slack by making the fit between tongue and groove tighter, and by filling the gap with some sort of velvety light trap. Some messing about suggested that the gap gets as big as 1.3mm or so, which seemed quite a lot. To get an idea of how much the fit needed to improve, I looked into depth of focus and used the calculation that can be found here...

https://en.wikipedia.org/wiki/Depth_of_focus

...that being...

depth of focus = 2 x f-number x circle of confusion x (image plane distance / focal length)

The circle of confusion was a bit of a stumbling block, so I rescanned the image of Blackness castle at 2400dpi and looked for thin features around the middle of the image. This shot was focused on the castle rather than at some hyperfocal distance, so was set close to infinity, meaning the image plane distance would be close to the lens's focal length. The various things I could find that looked like they were at the limit of what the lens could resolve were about 5 pixels wide. With the projected image width being 8.25" the width of the scan would be 19,800 pixels. So a 'best' circle of confusion in terms of what can be discerned in an extremely close-up view of the negative would be based on the factor derived from 5 / 19800 = 0.000253. When this is multiplied by the width of the projected image, we get a CoC with a size of 0.0021" or 0.053mm. I'll use millimeters for the remainder.

When the CoC is put into the formula, and if we assume image plane distance equals focal length (for focus at infinity), we get a total depth of focus at f/16 of 1.7mm, and at f/64 of 6.7mm. Note that this is the total depth of focus - the range that the image plane is allowed to move around in and still record objects that the lens can resolve to 0.053mm. In other words, it's not a symmetrical tolerance (the amount of deviation from a nominal centre distance), which would be +/- 1.7mm, etc.

It sounds like quite a lot, especially at f/64, but the minimum range - at the max aperture of f/16 - is what needs to be accounted for. If the lens is focused at something less than infinity, the image plane distance increases while the focal length stays the same, meaning the division terms become more than 1, with the result that, when multiplied by the other terms, the total depth of focus increases. In other words, for this lens, the geometry of the camera must be such that the position of the image plane stays within the minimum total depth of focus of 1.7mm (or stays within an error of +/-0.85mm).

Before I can start modifying things, I also need to consider the distance to the ground glass compared to the distance to the light sensitive surface in the plate holder. Asha mentioned that the plate holder was sourced later than the camera, and may not be an original part made by the camera maker - it could have been made for some other plate camera of similar design. Given that standards were thin on the ground back then, the distances to the GG and to the plate surface needs to be checked. It turns out that there's not a lot in it, although there are some deviations in the GG that suggest it's being flexed slightly. Both plates measure 15.0 to 15.1mm from the reference surface at all four corners. The GG measures 15.3mm at the two bottom corners, 15.8mm at the top left, and 15.1mm at the top-right. All measurement locations are when looking at the back of the camera, and with moderate finger pressure from behind to bring all surfaces snugly together.

Overall, this is good insofar as the deviations can be worked with. For the plate holder, all I have to do is add the veneer shims to bring both sides up snug with the back of the frame. There will still be a little bit of slack to allow the holder to slide in and out without too much friction, and this should be taken care of with some velvety light trap. The hinged frame that holds the GG will need some tweaking to bring the corner that's far away closer to about 15.3mm. (I haven't taken the glass out yet, so don't know what's causing the deviation.) If it's felt that the closer corner of the glass needs to move out, this area can be shimmed as needed. In summary, this doesn't look too bad - the plate holder looks good in terms of consistency of the distance to the image plane, and getting the GG to match looks like being little more than some careful removal of material from the recess it sits in.

This is all about trying to assess what adjustments need to be made, and how accurate they need to be - there's no point in trying to tweak things to less than a hair's breadth if it isn't needed. The idea is to try to get it right first time because doing remedial work after making adjustments could be problematic - the adjustments will be near-enough permanent, and I'm dealing with small bits of wood that are very old and possibly fragile. If I get something wrong and have to undo what I've done, I'll have to cut material away, and I could end up with less 'meat' to work with than I had at the first attempt.
 
Started adding the veneer to the tongue parts of the plate holder.

First thing to do is prepare the surfaces on the plate holder so that they take the glue well...

Marion Plate Holder 01.jpg


I happen to have this tiny shoulder plane, so used that to clean the faces, both to make sure any finish has been removed, and get them nice and flat. The side of the plane iron is exposed, which means the side of the plane can be pressed against the adjacent face to get the planed surface very perpendicular. Much quicker, neater and more accurate than trying to use some sort of abrasive. The shavnigs are very thin - only a couple of passes on each tongue, and the thickness of them reduced by about 0.1mm.

This is the veneer that will be used...

Veneer Strip 01.jpg


I got it years ago for something I was doing to an electric guitar, and had loads left over. It's 3mm wide mahogany, and 0.44mm thick (not the 0.7mm it says on the packet). The width is a tiny bit more than that of the tongues (less than a millimeter), which means minimal messing about to bring the veneer flush later.

Here are the first set of strips glued on...

Marion Plate Holder 02.jpg


Each holder has an edge with two short tongues, and one with those and a long tongue in the middle. The latter have a single strip of veneer applied, which I'll cut through later. The glue was Titebond Original, applied thinly to both surfaces. It tacked up very quickly, and the surfaces were pressed together with a flat bit of wood. With it tacking up so quickly, there was almost no slippage (only one bit moved a little and was eased back into position), so there should be no need to clamp. This will now be left to cure.
 
Started adding the veneer to the tongue parts of the plate holder.

First thing to do is prepare the surfaces on the plate holder so that they take the glue well...

View attachment 241631


I happen to have this tiny shoulder plane, so used that to clean the faces, both to make sure any finish has been removed, and get them nice and flat. The side of the plane iron is exposed, which means the side of the plane can be pressed against the adjacent face to get the planed surface very perpendicular. Much quicker, neater and more accurate than trying to use some sort of abrasive. The shavnigs are very thin - only a couple of passes on each tongue, and the thickness of them reduced by about 0.1mm.

This is the veneer that will be used...

View attachment 241632


I got it years ago for something I was doing to an electric guitar, and had loads left over. It's 3mm wide mahogany, and 0.44mm thick (not the 0.7mm it says on the packet). The width is a tiny bit more than that of the tongues (less than a millimeter), which means minimal messing about to bring the veneer flush later.

Here are the first set of strips glued on...

View attachment 241633


Each holder has an edge with two short tongues, and one with those and a long tongue in the middle. The latter have a single strip of veneer applied, which I'll cut through later. The glue was Titebond Original, applied thinly to both surfaces. It tacked up very quickly, and the surfaces were pressed together with a flat bit of wood. With it tacking up so quickly, there was almost no slippage (only one bit moved a little and was eased back into position), so there should be no need to clamp. This will now be left to cure.

Love your little sholder plane. I have a couple but not that small I have never seen that model before what make is it?
I would be tempted to make up the thickness and re-rout the shoulder afresh on a router table.
The chance of having the right book form slides for the camera is very slim ad they would have been made to hold glass plates not film or paper.
But it should be easy enough to shim the Ground glass holder as you only need to have the corners supported.
Usually velvet is only used on the open end of the dark slide entry. Everything else is fitted wood to wood including the light trap strips and grooves.
When they are made both parts have identical grooves and then one has the strips inserted.
 
The plane is made by Veritas...

https://www.axminster.co.uk/veritas-miniature-shoulder-plane-952802

They do a few others as well. I fancy the little low angle block plane.

I just tried the fit after the second layer of veneer, and it looks pretty good - still a little bit of play, but maybe enough for the velvet to make up the difference. I won't add any more until I've had a closer look at the GG fitting and worked out why the corner depths from the lens side on that measure differently compared to the pseudo-plate MDF spacers in the film holder, which are both very consistent corner to corner. The GG looks to be supported all the way round by a rebate rather than just at the corners (I see no gaps when looking at the edges from the ground side).

This camera has the velvet strips at both sides - the top and bottom edges are light trapped due to the slidey bits, but the left and right are just two flat faces mated together. To be clear, the light leak isn't between the dark slide and the entry in the plate holder, it's between the plate holder and the back of the camera body where it slides into the grooves that are normally occupied by the GG frame.
 
Just been trying the plate holder in the camera with two layers of veneer. The light leaks have improved, but I'm still getting a bit, especially on the right hand side where there is a bit more front-to-back play in the plate holder compared to the left. I've added another layer of veneer to the tongues at the right, and will work them down to get a fit that's similar to the left. While faffing about with more finicky gluing, I found this stamped on one half of the plate holder, on the frame near where the dark slide is pulled out...

Marion Plate Holder 03.jpg

It says "GANDOLFI'S", so it's a Gandolfi plate holder.

In other news, I found some velvet ribbon in Hobbycraft today, so bought a couple of meters. The existing velvet light traps are in channels on either side of the frame, and these seem to be about 0.6mm deep. If I do have to replace these, I'm pretty confident that the new stuff will work - it's about 1.4 to 1.5mm thick before compressing the fibres, and will have some double sided tape underneath it. It's a bit wider than the original by about 2mm, so I either have to trim it down or widen the channels. Trimming will be tricky, and could result in fraying, so I'll see how it goes.

I also had a close look at the ground glass (still not removed). It has pencil marks on in, and I tried rubbing them off, which seemed to work to an extent, but not great. There were sill traces of the marks, and the ground surface changed a little where the eraser was rubbed on it. Not sure if the latter is the result of cleaning rather than damage to ground surface (doubtful of that given how hard glass is). I'll probably try giving it a wash once I take it out, so will see how it looks after that, regarding both the residual pencil marks and the slight sheen in the bits that had the eraser on them. If that doesn't work, I can regrind it. A careful look at the surface through a loupe, and at a plate I've used for grinding other glass suggests the 600 grit grinding powder I have should be fine. If all else fails, I can make a new GG.
 
Good progress this evening. After quite a lot of fettling, it's looking like the adjustments to the plate holder are just about complete.

I added a couple of extra bits of veneer here and there to get a snug fit in the grooves, and found that the light leaks had gone (one was still apparent until a final layer of veneer was added at one tongue near a corner, and substantially sanded back down to make the small adjustment in thickness needed). With a bit of luck, I won't need to replace the velvet light trap strips.

Here are a couple of shots of the veneered bits...

Marion Plate Holder 04.jpg

The leading ends (on the right in this shot) are faired to help with insertion into the back of the camera. They only need to have the working thickness for some of the length of the tongue, so it's fine to do this.

There were various little bits of damage in places. In this one, I've cut the outline of the veneer to match the space where there used to be wood...

Marion Plate Holder 05.jpg

The right-hand end of this is also faired because it needs to get into the groove as the holder is inserted (it's the same with them all).

First coat of shellac has been applied...

Marion Plate Holder 06.jpg

That's Liberon Garnet shellac flakes dissolved in bio-ethanol. It's a basic amber shellac. It looks quite light compared to the original finish, but should darken once some more coats have been applied (I experimented with a separate bit of the veneer). It might not match perfectly because the veneer is a lighter colour than the base wood of the camera, but the main thing is to protect it from moisture.
 
While fettling the plate holder halves, I was having some trouble getting a nice smooth fit. After quite a bit of checking and measuring, it turned out that the space between the parts that overlap the tongues in the plate holder was just a bit too narrow (in other words, not between the bottoms of the two grooves, but the shorter distance between the bits that form the grooves and stop the plate holder from falling off). It was getting tight just near the end of the holder insertion, and it turned out that the space narrowed at the far end, from 194mm down to about 193mm.

Rather than take material off the plate holder sides, I decided to adjust the frame on the camera....

Marion GG Frame 01.jpg

This was done with a low angle block plane to skim little thin bits off, a couple of passes at a time, and then trying the two halves of the plate holder for fit. You can see the bare wood along the inner face where it was planed away (and more removed towards the left - still some original finish at the right).

With two coats of shellac on this so far, the match is spot on...

Marion GG Frame 02.jpg

I may have to do a bit more fettling once the finishing is done (it could affect the snug sliding fit), and as I said, I'll recheck for light leaks once the bits are all back together. Overall, though, it's starting to look good - much happier with the plate holder now.
 
Overall, though, it's starting to look good - much happier with the plate holder now.

(y)

It has to be so satisfying when the effort pays off….Well done!
 
Back to this for a bit. I previously mentioned that the septum in the plate holder was a looking a bit tatty...

Marion Septum 01.jpg


Marion Septum 02.jpg


I gave it a sand and tried painting one side with the Rustoleum satin black paint, on the assumption that it would give a robust finish...

Marion Septum 03.jpg

A bit too shiny.
 
So I had a go with the matt black...

Marion Septum 04.jpg


Too patchy. I then didn't touch it for ages, but decided a few days ago to give it a try with an airbrush instead.

First thing was to treat it with "Satan's Vomit" paint stripper, which made very short work of both the new paint and the original stuff that was still underneath...

Marion Septum 05.jpg


Marion Septum 06.jpg

It looks like the metal is galvanised steel. A bit of wet sanding with some 1200 grit paper got the last of the paint off.
 
It was then dangled in my bench-top spray booth and given a coat of black acrylic primer...

Marion Septum 07.jpg

Then left to cure for a day, before getting sprayed with Humbrol matt black enamel (pongy stuff - each side was left for a good hour with the extraction running to vent the fumes outside). This was then left for a couple of days to get the enamel on the way to being cured.

I refitted the septum into the holder today...

Marion Septum 08.jpgMarion Septum 09.jpg

I'm much happier with the finish now. It looks like it leans a bit towards blue in the photos, but looks dead black in reality. I also checked the paints to see if they fluoresced in UV light, but there doesn't seem to be anything. I hadn't considered this when I first painted it, but it later struck me as a possible issue because the albumen on glass that I plan to use for the plates is very transparent - not translucent like a gelatin coating. If the paint fluoresced, there would have been some pretty bad halation.

I've left out the two MDF spacers for now. If you look up at the hand-painted version, some damage can be seen to the finish, probably as a result of reassembling too soon after painting. The spacers apply pressure to the leaf spring on one side and the middle of the septum on the other. I want it to have the maximum time to cure fully, so the spacers stay out for now. Don't know yet if the new finish will be robust, so that will have to wait for now.
 
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Great to see an update, really looking forward to seeing the results from this.
 
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